draft-ietf-mpls-diff-ext-07.txt   draft-ietf-mpls-diff-ext-08.txt 
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Ram Krishnan Ram Krishnan
Lucent Technologies Lucent Technologies
Pierrick Cheval Pierrick Cheval
Alcatel Alcatel
Juha Heinanen Juha Heinanen
Telia Finland Telia Finland
IETF Internet Draft IETF Internet Draft
Expires: February, 2001 Expires: August, 2001
Document: draft-ietf-mpls-diff-ext-07.txt August, 2000 Document: draft-ietf-mpls-diff-ext-08.txt February, 2001
MPLS Support of Differentiated Services MPLS Support of Differentiated Services
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. all provisions of Section 10 of RFC2026.
Internet-Drafts are Working documents of the Internet Engineering Internet-Drafts are Working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
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at any time. It is inappropriate to use Internet-Drafts as reference at any time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt http://www.ietf.org/ietf/1id-abstracts.txt
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Abstract Abstract
This document defines a flexible solution for support of This document defines a flexible solution for support of
Differentiated Services (Diff-Serv) over Multi-Protocol Label Differentiated Services (Diff-Serv) over Multi-Protocol Label
Switching (MPLS) networks. Switching (MPLS) networks.
This solution allows the MPLS network administrator to select how This solution allows the MPLS network administrator to select how
Diff-Serv Behavior Aggregates (BAs) are mapped onto Label Switched Diff-Serv Behavior Aggregates (BAs) are mapped onto Label Switched
Paths (LSPs) so that he/she can best match the Diff-Serv, Traffic Paths (LSPs) so that he/she can best match the Diff-Serv, Traffic
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This document specifies a solution for supporting the Diff-Serv This document specifies a solution for supporting the Diff-Serv
Behavior Aggregates whose corresponding PHBs are currently defined Behavior Aggregates whose corresponding PHBs are currently defined
(in [DIFF_HEADER], [DIFF_AF], [DIFF_EF]) over an MPLS network. This (in [DIFF_HEADER], [DIFF_AF], [DIFF_EF]) over an MPLS network. This
solution also offers flexibility for easy support of PHBs that may solution also offers flexibility for easy support of PHBs that may
be defined in the future. be defined in the future.
As mentioned in [DIFF_HEADER], "Service providers are not required As mentioned in [DIFF_HEADER], "Service providers are not required
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to use the same node mechanisms or configurations to enable service to use the same node mechanisms or configurations to enable service
differentiation within their networks, and are free to configure the differentiation within their networks, and are free to configure the
node parameters in whatever way that is appropriate for their node parameters in whatever way that is appropriate for their
service offerings and traffic engineering objectives". Thus, the service offerings and traffic engineering objectives". Thus, the
solution defined in this document gives Service Providers solution defined in this document gives Service Providers
flexibility in selecting how Diff-Serv classes of service are Routed flexibility in selecting how Diff-Serv classes of service are Routed
or Traffic Engineered within their domain (e.g. separate classes of or Traffic Engineered within their domain (e.g. separate classes of
services supported via separate LSPs and Routed separately, all services supported via separate LSPs and Routed separately, all
classes of service supported on the same LSP and Routed together). classes of service supported on the same LSP and Routed together).
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"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in
this document are to be interpreted as described in RFC 2119. this document are to be interpreted as described in RFC 2119.
The reader is assumed to be familiar with the terminology of The reader is assumed to be familiar with the terminology of
[MPLS_ARCH], [MPLS_ENCAPS], [MPLS_ATM] and [MPLS_FR] including the [MPLS_ARCH], [MPLS_ENCAPS], [MPLS_ATM] and [MPLS_FR] including the
following: following:
EXP EXPerimental (bits) EXP EXPerimental (bits)
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FEC Forwarding Equivalency Class FEC Forwarding Equivalency Class
FTN FEC-To-NHLFE Map FTN FEC-To-NHLFE Map
ILM Incoming Label Map ILM Incoming Label Map
LC-ATM Label Switching Controlled-ATM (interface) LC-ATM Label Switching Controlled-ATM (interface)
LC-FR Label Switching Controlled-Frame Relay (interface) LC-FR Label Switching Controlled-Frame Relay (interface)
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are applied to the Behavior Aggregate(s) belonging to a are applied to the Behavior Aggregate(s) belonging to a
given OA. For example, AF1x is a PSC comprising the given OA. For example, AF1x is a PSC comprising the
AF11, AF12 and AF13 PHBs. EF is an example of PSC AF11, AF12 and AF13 PHBs. EF is an example of PSC
comprising a single PHB, the EF PHB. comprising a single PHB, the EF PHB.
The following acronyms are also used: The following acronyms are also used:
CLP Cell Loss Priority CLP Cell Loss Priority
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DE Discard Eligibility DE Discard Eligibility
SNMP Simple Network Management Protocol SNMP Simple Network Management Protocol
Finally, the following acronyms are defined in this specification: Finally, the following acronyms are defined in this specification:
E-LSP EXP-Inferred-PSC LSP E-LSP EXP-Inferred-PSC LSP
L-LSP Label-Only-Inferred-PSC LSP L-LSP Label-Only-Inferred-PSC LSP
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since the PSC can be fully inferred from the label without any other since the PSC can be fully inferred from the label without any other
information (e.g. regardless of the EXP field value). Detailed information (e.g. regardless of the EXP field value). Detailed
operations of L-LSPs are specified in section 4 below. operations of L-LSPs are specified in section 4 below.
1.4 Overall Operations 1.4 Overall Operations
For a given FEC, and unless media specific restrictions apply as For a given FEC, and unless media specific restrictions apply as
identified in the sections 7, 8 and 9 below, this specification identified in the sections 7, 8 and 9 below, this specification
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allows any one of the following combinations within an MPLS Diff- allows any one of the following combinations within an MPLS Diff-
Serv domain: Serv domain:
- zero or any number of E-LSPs, and - zero or any number of E-LSPs, and
- zero or any number of L-LSPs. - zero or any number of L-LSPs.
The network administrator selects the actual combination of LSPs The network administrator selects the actual combination of LSPs
from the set of allowed combinations and selects how the Behavior from the set of allowed combinations and selects how the Behavior
Aggregates are actually transported over this combination of LSPs, Aggregates are actually transported over this combination of LSPs,
in order to best match his/her environment and objectives in terms in order to best match his/her environment and objectives in terms
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1.6 Bandwidth Reservation for E-LSPs and L-LSPs 1.6 Bandwidth Reservation for E-LSPs and L-LSPs
Regardless of which label binding protocol is used, E-LSPs and Regardless of which label binding protocol is used, E-LSPs and
L-LSPs may be established without bandwidth reservation or with L-LSPs may be established without bandwidth reservation or with
bandwidth reservation. bandwidth reservation.
Establishing an E-LSP or L-LSP with bandwidth reservation means that Establishing an E-LSP or L-LSP with bandwidth reservation means that
bandwidth requirements for the LSP are signaled at LSP establishment bandwidth requirements for the LSP are signaled at LSP establishment
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time. Such signaled bandwidth requirements may be used by LSRs at time. Such signaled bandwidth requirements may be used by LSRs at
establishment time to perform admission control of the signaled LSP establishment time to perform admission control of the signaled LSP
over the Diff-Serv resources provisioned (e.g. via configuration, over the Diff-Serv resources provisioned (e.g. via configuration,
SNMP or policy protocols) for the relevant PSC(s). Such signaled SNMP or policy protocols) for the relevant PSC(s). Such signaled
bandwidth requirements may also be used by LSRs at establishment bandwidth requirements may also be used by LSRs at establishment
time to perform adjustment to the Diff-Serv resources associated time to perform adjustment to the Diff-Serv resources associated
with the relevant PSC(s) (e.g. adjust PSC scheduling weight). with the relevant PSC(s) (e.g. adjust PSC scheduling weight).
Note that establishing an E-LSP or L-LSP with bandwidth reservation Note that establishing an E-LSP or L-LSP with bandwidth reservation
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visible to an LSR, the way to determine the PHB to be applied to a visible to an LSR, the way to determine the PHB to be applied to a
received packet and to encode the PHB into a transmitted packet is received packet and to encode the PHB into a transmitted packet is
different than a non-MPLS Diff-Serv Router. different than a non-MPLS Diff-Serv Router.
Thus, in order to describe Label Forwarding by Diff-Serv LSRs, we Thus, in order to describe Label Forwarding by Diff-Serv LSRs, we
model the LSR Diff-Serv label switching behavior as comprising four model the LSR Diff-Serv label switching behavior as comprising four
stages: stages:
- Incoming PHB Determination (A) - Incoming PHB Determination (A)
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- Outgoing PHB Determination with Optional Traffic Conditioning(B) - Outgoing PHB Determination with Optional Traffic Conditioning(B)
- Label Swapping (C) - Label Forwarding (C)
- Encoding of Diff-Serv information into Encapsulation Layer (EXP, - Encoding of Diff-Serv information into Encapsulation Layer (EXP,
CLP, DE, User_Priority) (D) CLP, DE, User_Priority) (D)
Each stage is described in more details in the following sections. Each stage is described in more details in the following sections.
Obviously, to enforce the Diff-Serv service differentiation the LSR Obviously, to enforce the Diff-Serv service differentiation the LSR
MUST also apply the forwarding treatment corresponding to the MUST also apply the forwarding treatment corresponding to the
Outgoing PHB. Outgoing PHB.
This model is illustrated below: This model is illustrated below:
--Inc_label(*)--------------------------->I===I---Outg_label (**)--> --Inc_label(s)(*)------------------------>I===I--Outg_label(s)(&)-->
\ I I \ \ I I \
\---->I===I I C I \-->I===I--Encaps-> \---->I===I I C I \-->I===I--Encaps->
I A I I===I--Outg_PHB->I===I I D I (**) I A I I===I--Outg_PHB->I===I I D I (&)
-Encaps->I===I--Inc_PHB->I B I \ /->I===I -Encaps->I===I--Inc_PHB->I B I \ /->I===I
(*) I===I \--------+ (*) I===I \--------+
\----Forwarding--> \----Forwarding-->
Treatment Treatment
(PHB) (PHB)
`Encaps' designates the Diff-Serv related information encoded in the "Encaps" designates the Diff-Serv related information encoded in the
MPLS Encapsulation layer (eg EXP field, ATM CLP, Frame Relay DE, MPLS Encapsulation layer (eg EXP field, ATM CLP, Frame Relay DE,
802.1 User_Priority) 802.1 User_Priority)
(*) when the LSR behaves as an MPLS ingress node, the incoming (*) when the LSR behaves as an MPLS ingress node, the incoming
packet may be received unlabelled. packet may be received unlabelled.
(**) when the LSR behaves as an MPLS egress node, the outgoing (&) when the LSR behaves as an MPLS egress node, the outgoing packet
packet may be transmitted unlabelled. may be transmitted unlabelled.
This model is presented here to describe the functional operations This model is presented here to describe the functional operations
of Diff-Serv LSRs and does not constrain actual implementation. of Diff-Serv LSRs and does not constrain actual implementation.
2.2 Incoming PHB Determination 2.2 Incoming PHB Determination
This stage determines which Behavior Aggregate the received packet This stage determines which Behavior Aggregate the received packet
belongs to. belongs to.
2.2.1 Incoming PHB Determination Considering a Label Stack Entry 2.2.1 Incoming PHB Determination Considering a Label Stack Entry
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PHB Determination considering a given received label stack entry PHB Determination considering a given received label stack entry
and/or received incoming MPLS encapsulation information depending on and/or received incoming MPLS encapsulation information depending on
the incoming LSP type and depending on the incoming MPLS the incoming LSP type and depending on the incoming MPLS
encapsulation. encapsulation.
Section 2.6 provides the details of which label stack entry to Section 2.6 provides the details of which label stack entry to
consider for the Incoming PHB Determination depending on the consider for the Incoming PHB Determination depending on the
supported Diff-Serv tunneling mode. supported Diff-Serv tunneling mode.
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2.2.2 Incoming PHB Determination Considering IP Header 2.2.2 Incoming PHB Determination Considering IP Header
Section 2.6 provides the details of when the IP Header is to be Section 2.6 provides the details of when the IP Header is to be
considered for incoming PHB determination depending on the supported considered for incoming PHB determination depending on the supported
Diff-Serv tunneling model. In those cases where the IP header is to Diff-Serv tunneling model. In those cases where the IP header is to
be used, this stage operates exactly as with a non-MPLS IP Diff-Serv be used, this stage operates exactly as with a non-MPLS IP Diff-Serv
Router and uses the DS field to determine incoming PHB. Router and uses the DS field to determine incoming PHB.
2.3 Outgoing PHB Determination With Optional Traffic Conditioning 2.3 Outgoing PHB Determination With Optional Traffic Conditioning
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demotion or promotion. It is outside the scope of this demotion or promotion. It is outside the scope of this
specification. For the purpose of specifying Diff-Serv over MPLS specification. For the purpose of specifying Diff-Serv over MPLS
forwarding, we simply note that the PHB to be actually enforced, and forwarding, we simply note that the PHB to be actually enforced, and
conveyed to downstream LSRs, by an LSR (referred to as "outgoing conveyed to downstream LSRs, by an LSR (referred to as "outgoing
PHB") may be different to the PHB which had been associated with the PHB") may be different to the PHB which had been associated with the
packet by the previous LSR (referred to as "incoming PHB"). packet by the previous LSR (referred to as "incoming PHB").
When the traffic conditioning stage is not present, the "outgoing When the traffic conditioning stage is not present, the "outgoing
PHB" is simply identical to the "incoming PHB". PHB" is simply identical to the "incoming PHB".
2.4 Label Swapping 2.4 Label Forwarding
[MPLS_ARCH] describes how label swapping is performed by LSRs on [MPLS_ARCH] describes how label swapping is performed by LSRs on
incoming labeled packets using an Incoming Label Map (ILM), where incoming labeled packets using an Incoming Label Map (ILM), where
each incoming label is mapped to one or multiple NHLFEs. [MPLS_ARCH] each incoming label is mapped to one or multiple NHLFEs. [MPLS_ARCH]
also describes how label imposition is performed by LSRs on incoming also describes how label imposition is performed by LSRs on incoming
unlabelled packets using a FEC-to-NHLFEs Map (FTN), where each unlabelled packets using a FEC-to-NHLFEs Map (FTN), where each
incoming FEC is mapped to one or multiple NHLFEs. incoming FEC is mapped to one or multiple NHLFEs.
A Diff-Serv Context for a label is defined as comprising: A Diff-Serv Context for a label is defined as comprising:
- `LSP type (ie E-LSP or L-LSP)' - `LSP type (ie E-LSP or L-LSP)'
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Serv Context is stored in the NHLFE for each outgoing label which is Serv Context is stored in the NHLFE for each outgoing label which is
swapped or pushed. swapped or pushed.
This Diff-Serv Context information is populated into the ILM and the This Diff-Serv Context information is populated into the ILM and the
FTN at label establishment time. FTN at label establishment time.
If the label corresponds to an E-LSP for which no EXP<-->PHB mapping If the label corresponds to an E-LSP for which no EXP<-->PHB mapping
has been explicitly signaled at LSP setup, the `supported PHBs' is has been explicitly signaled at LSP setup, the `supported PHBs' is
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populated with the set of PHBs of the preconfigured populated with the set of PHBs of the preconfigured
EXP<-->PHB Mapping, which is discussed below in section 3.2.1. EXP<-->PHB Mapping, which is discussed below in section 3.2.1.
If the label corresponds to an E-LSP for which an EXP<-->PHB mapping If the label corresponds to an E-LSP for which an EXP<-->PHB mapping
has been explicitly signaled at LSP setup, the `supported PHBs' is has been explicitly signaled at LSP setup, the `supported PHBs' is
populated with the set of PHBs of the signaled EXP<-->PHB mapping. populated with the set of PHBs of the signaled EXP<-->PHB mapping.
If the label corresponds to an L-LSP, the `supported PHBs' is If the label corresponds to an L-LSP, the `supported PHBs' is
populated with the set of PHBs forming the PSC that is signaled at populated with the set of PHBs forming the PSC that is signaled at
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Serv information in the transmitted packet (e.g. MPLS Shim EXP, ATM Serv information in the transmitted packet (e.g. MPLS Shim EXP, ATM
CLP, Frame Relay DE, 802.1 User_Priority). CLP, Frame Relay DE, 802.1 User_Priority).
2.5.1 Encoding Diff-Serv Information Into Transmitted Label Entry 2.5.1 Encoding Diff-Serv Information Into Transmitted Label Entry
Sections 3.5 and 4.5 provide the details on how to perform Diff-Serv Sections 3.5 and 4.5 provide the details on how to perform Diff-Serv
information encoding into a given transmitted label stack entry information encoding into a given transmitted label stack entry
and/or transmitted MPLS encapsulation information depending on the and/or transmitted MPLS encapsulation information depending on the
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corresponding outgoing LSP type and depending on the MPLS corresponding outgoing LSP type and depending on the MPLS
encapsulation. encapsulation.
Section 2.6 provides the details of which label stack entry to Section 2.6 provides the details of which label stack entry to
perform Diff-Serv information encoding into depending on the perform Diff-Serv information encoding into depending on the
supported Diff-Serv tunneling mode. supported Diff-Serv tunneling mode.
2.5.2 Encoding Diff-Serv Information Into Transmitted IP Header 2.5.2 Encoding Diff-Serv Information Into Transmitted IP Header
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obviously not an issue at all. In situations where this obviously not an issue at all. In situations where this
information is meaningful at the LSP Egress, then it must information is meaningful at the LSP Egress, then it must
somehow be carried in some other means. somehow be carried in some other means.
The two conceptual models for Diff-Serv tunneling over IP Tunnels The two conceptual models for Diff-Serv tunneling over IP Tunnels
defined in [DIFF_TUNNEL] are applicable and useful to Diff-Serv over defined in [DIFF_TUNNEL] are applicable and useful to Diff-Serv over
MPLS but their respective detailed operations is somewhat different MPLS but their respective detailed operations is somewhat different
over MPLS. These two models are the Pipe Model and the Uniform over MPLS. These two models are the Pipe Model and the Uniform
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Model. Their operations over MPLS are specified in the following Model. Their operations over MPLS are specified in the following
sections. Discussion and definition of alternative tunneling models sections. Discussion and definition of alternative tunneling models
are outside the scope of this specification. are outside the scope of this specification.
2.6.2 Pipe Model 2.6.2 Pipe Model
With the Pipe Model, MPLS tunnels (aka LSPs) are used to hide the With the Pipe Model, MPLS tunnels (aka LSPs) are used to hide the
intermediate MPLS nodes between LSP Ingress and Egress from the intermediate MPLS nodes between LSP Ingress and Egress from the
Diff-Serv perspective. In this model, the LSP Egress uses the Diff- Diff-Serv perspective.
Serv information conveyed from the LSP Ingress inside the
encapsulated header (be it an IP Header or an MPLS Header) and
ignores the Diff-Serv information conveyed in the encapsulating
header.
In this model, tunneled packets must convey two meaningful pieces of In this model, tunneled packets must convey two meaningful pieces of
Diff-Serv information: Diff-Serv information:
- the Diff-Serv information which is meaningful to intermediate - the Diff-Serv information which is meaningful to intermediate
nodes along the LSP span (which we refer to as the "LSP Diff- nodes along the LSP span including the LSP Egress (which we
Serv Information"). This LSP Diff-Serv Information is not refer to as the "LSP Diff-Serv Information"). This LSP Diff-Serv
meaningful at the LSP Egress: Whether Traffic Conditioning at Information is not meaningful beyond the LSP Egress: Whether
intermediate nodes on the LSP span affects the LSP Diff-Serv Traffic Conditioning at intermediate nodes on the LSP span
information or not, this updated Diff-Serv information is not affects the LSP Diff-Serv information or not, this updated Diff-
considered meaningful at the LSP Egress and is ignored. Serv information is not considered meaningful beyond the LSP
- the Diff-Serv information which is meaningful at the LSP Egress Egress and is ignored.
(which we refer to as the "Tunneled Diff-Serv Information"). - the Diff-Serv information which is meaningful beyond the LSP
This information is to be conveyed by the LSP Ingress to the LSP Egress (which we refer to as the "Tunneled Diff-Serv
Egress. This Diff-Serv information is not meaningful to the Information"). This information is to be conveyed by the LSP
intermediate nodes on the LSP span. Ingress to the LSP Egress. This Diff-Serv information is not
meaningful to the intermediate nodes on the LSP span.
Operation of the Pipe Model without PHP is illustrated below: Operation of the Pipe Model without PHP is illustrated below:
========== LSP =============================> ========== LSP =============================>
---Swap--(M)--...--Swap--(M)--Swap---- ---Swap--(M)--...--Swap--(M)--Swap----
/ (outer header) \ / (outer header) \
(M) (M) (M) (M)
/ \ / \
>--(m)-Push.................(m).....................Pop--(m)--> >--(m)-Push.................(m).....................Pop--(m)-->
I (inner header) E I (inner header) E (M*)
(M) represents the "LSP Diff-Serv information (M) represents the "LSP Diff-Serv information"
(m) represents the "Tunneled Diff-Serv information" (m) represents the "Tunneled Diff-Serv information"
(*) The LSP Egress considers the LSP Diff-Serv information received
in the outer header (i.e. before the pop) in order to apply its
Diff-Serv forwarding treatment (i.e. actual PHB)
I represents the LSP ingress node I represents the LSP ingress node
E represents the LSP egress node E represents the LSP egress node
Operation of the Pipe Model with PHP is illustrated below: With the Pipe Model, the "LSP Diff-Serv Information" needs to be
conveyed to LSP Egress so that it applies its forwarding treatment
=========== LSP ============================> based on it. The "Tunneled Diff-Serv information" also needs to be
conveyed to the LSP Egress so it can be conveyed further downstream.
---Swap--(M)--...--Swap------
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/ (outer header) \
(M) (M)
/ \
>--(m)-Push.................(m).............Pop-(m)--E--(m)-->
I (inner header) P (M*)
(M) represents the "LSP Diff-Serv information Since both Diff-Serv information need to be conveyed to the LSP
(m) represents the "Tunneled Diff-Serv information" Egress, the Pipe Model operates only without PHP.
(*) The Penultimate LSR considers the LSP Diff-Serv information
received in the outer header (i.e. before the pop) in order to
apply its Diff-Serv forwarding treatment (ie actual PHB)
I represents the LSP ingress node
P represents the LSP penultimate node
E represents the LSP egress node
The Pipe Model is particularly appropriate to environments in which The Pipe Model is particularly appropriate to environments in which:
the incoming interface of the LSP Ingress and the outgoing interface - the cloud upstream of the incoming interface of the LSP Ingress
of the LSP Egress are in Diff-Serv domains which use a common set of and the cloud downstream of the outgoing interface of the LSP
Diff-Serv service provisioning policies and PHB definitions, while Egress are in Diff-Serv domains which use a common set of Diff-
Serv service provisioning policies and PHB definitions, while
the LSP spans one (or more) Diff-Serv domain(s) which use(s) a the LSP spans one (or more) Diff-Serv domain(s) which use(s) a
different set of Diff-Serv service provisioning policies and PHB different set of Diff-Serv service provisioning policies and PHB
definitions. definitions
- the outgoing interface of the LSP Egress is in the (last) Diff-
Serv domain spanned by the LSP.
As an example, consider the case where a service provider is As an example, consider the case where a service provider is
offering an MPLS VPN service (see [MPLS_VPN] for an example of MPLS offering an MPLS VPN service (see [MPLS_VPN] for an example of MPLS
VPN architecture) including Diff-Serv differentiation. Say that a VPN architecture) including Diff-Serv differentiation. Say that a
collection of sites are interconnected via such an MPLS VPN service. collection of sites are interconnected via such an MPLS VPN service.
Now say that this collection of sites are managed under a common Now say that this collection of sites are managed under a common
administration and are also supporting Diff-Serv service administration and are also supporting Diff-Serv service
differentiation. If the VPN site administration and the Service differentiation. If the VPN site administration and the Service
Provider are not sharing the exact same Diff-Serv policy (for Provider are not sharing the exact same Diff-Serv policy (for
instance not supporting the same number of PHBs), then operation of instance not supporting the same number of PHBs), then operation of
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intermediate network nodes. intermediate network nodes.
The Pipe Model MUST be supported. The Pipe Model MUST be supported.
For support of the Pipe Model over a given LSP without PHP, an LSR For support of the Pipe Model over a given LSP without PHP, an LSR
performs the Incoming PHB Determination and the Diff-Serv performs the Incoming PHB Determination and the Diff-Serv
information Encoding in the following manner: information Encoding in the following manner:
- when receiving an unlabelled packet, the LSR performs Incoming - when receiving an unlabelled packet, the LSR performs Incoming
PHB Determination considering the received IP Header. PHB Determination considering the received IP Header.
- when receiving a labeled packet, the LSR performs Incoming PHB - when receiving a labeled packet, the LSR performs Incoming PHB
Determination considering the header (label entry or IP header) Determination considering the outer label entry in the received
which is used to do the actual forwarding. In particular, when a label stack. In particular, when a pop operation is to be
performed for the considered LSP, the LSR performs Incoming PHB
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MPLS Support of Diff-Serv August 2000
pop operation is to be performed for the considered LSP, the LSR
performs Incoming PHB Determination AFTER the pop.
- when performing a swap-only operation for the considered LSP,
the LSR encodes Diff-Serv Information in the transmitted label
entry corresponding to the swapped label
- when performing a push operation for the considered LSP, the - when performing a push operation for the considered LSP, the
LSR: LSR:
o encodes Diff-Serv Information corresponding to the o encodes Diff-Serv Information corresponding to the
OUTGOING PHB in the transmitted label entry corresponding OUTGOING PHB in the transmitted label entry corresponding
to the pushed label. to the pushed label.
o encodes Diff-Serv Information corresponding to the o encodes Diff-Serv Information corresponding to the
INCOMING PHB in the encapsulated header (swapped label INCOMING PHB in the encapsulated header (swapped label
entry or IP header). entry or IP header).
For support of the Pipe Model over a given LSP with PHP, an LSR Le Faucheur et. al 13
performs Incoming PHB Determination and Diff-Serv information MPLS Support of Diff-Serv February 2001
- when performing a swap-only operation for the considered LSP,
the LSR encodes Diff-Serv Information in the transmitted label
entry that contains the swapped label
- when performing a pop operation for the considered LSP, the LSR
does not perform Encoding of Diff-Serv Information into the
header exposed by the pop operation (i.e. the LSR leaves the
exposed header "as is").
2.6.2.1 Short Pipe Model
The Short Pipe Model is an optional variation over the Pipe Model
described above. The only difference is that, with the Short Pipe
Model, the Diff-Serv forwarding treatment at the LSP Egress is
applied based on the "Tunneled Diff-Serv Information" (i.e. Diff-
Serv information conveyed in the encapsulated header) rather than on
the "LSP Diff-Serv information" (i.e. Diff-Serv information conveyed
in the encapsulating header).
Operation of the Short Pipe Model without PHP is illustrated below:
========== LSP =============================>
---Swap--(M)--...--Swap--(M)--Swap----
/ (outer header) \
(M) (M)
/ \
>--(m)-Push.................(m).....................Pop--(m)-->
I (inner header) E
(M) represents the "LSP Diff-Serv information"
(m) represents the "Tunneled Diff-Serv information"
I represents the LSP ingress node
E represents the LSP egress node
Since the LSP Egress applies its forwarding treatment based on the
"Tunneled Diff-Serv Information", the "LSP Diff-Serv information"
does not need to be conveyed by the penultimate node to the LSP
Egress. Thus the Short Pipe Model can also operate with PHP.
Operation of the Short Pipe Model with PHP is illustrated below:
=========== LSP ============================>
---Swap--(M)--...--Swap------
/ (outer header) \
(M) (M)
/ \
>--(m)-Push.................(m).............Pop-(m)--E--(m)-->
I (inner header) P (M*)
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MPLS Support of Diff-Serv February 2001
(M) represents the "LSP Diff-Serv information"
(m) represents the "Tunneled Diff-Serv information"
(*) The Penultimate LSR considers the LSP Diff-Serv information
received in the outer header (i.e. before the pop) in order to
apply its Diff-Serv forwarding treatment (i.e. actual PHB)
I represents the LSP ingress node
P represents the LSP penultimate node
E represents the LSP egress node
The Short Pipe Model is particularly appropriate to environments in
which:
- the cloud upstream of the incoming interface of the LSP Ingress
and the cloud downstream of the outgoing interface of the LSP
Egress are in Diff-Serv domains which use a common set of Diff-
Serv service provisioning policies and PHB definitions, while
the LSP spans one (or more) Diff-Serv domain(s) which use(s) a
different set of Diff-Serv service provisioning policies and PHB
definitions
- the outgoing interface of the LSP Egress is in the same Diff-
Serv domain as the cloud downstream of it.
Since each outgoing interface of the LSP Egress is in the same Diff-
Serv domain as the cloud downstream of it, each outgoing interface
may potentially be in a different Diff-Serv domain, and the LSP
Egress needs to be configured with awareness of every corresponding
Diff-Serv policy. This operational overhead is justified in some
situations where the respective downstream Diff-Serv policies are
better suited to offering service differentiation over each egress
interface than the common Diff-Serv policy used on the LSP span. An
example of such a situation is where a Service Provider offers an
MPLS VPN service and where some VPN users request that their own VPN
Diff-Serv policy be applied to control service differentiation on
the dedicated link from the LSP Egress to the destination VPN site,
rather than the Service Provider's Diff-Serv policy.
The Short Pipe Model MAY be supported.
For support of the Short Pipe Model over a given LSP without PHP, an
LSR performs the Incoming PHB Determination and the Diff-Serv
information Encoding in the same manner as with the Pipe Model with
the following exception:
- when receiving a labeled packet, the LSR performs Incoming PHB
Determination considering the header (label entry or IP header)
which is used to do the actual forwarding. In particular, when a
pop operation is to be performed for the considered LSP, the LSR
performs Incoming PHB Determination AFTER the pop.
For support of the Short Pipe Model over a given LSP with PHP, an
LSR performs Incoming PHB Determination and Diff-Serv information
Encoding in the same manner as without PHP with the following Encoding in the same manner as without PHP with the following
exceptions: exceptions:
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- the Penultimate LSR performs Incoming PHB Determination - the Penultimate LSR performs Incoming PHB Determination
considering the outer label entry in the received label stack. considering the outer label entry in the received label stack.
In other words, when a pop operation is to be performed for the In other words, when a pop operation is to be performed for the
considered LSP, the Penultimate LSR performs Incoming PHB considered LSP, the Penultimate LSR performs Incoming PHB
Determination BEFORE the pop. Determination BEFORE the pop.
- the Penultimate LSR does not perform Encoding of Diff-Serv Note that the behavior of the Penultimate LSR in the Short Pipe Mode
Information into the header exposed by the pop operation (i.e. with PHP, is identical to the behavior of the LSP Egress in the Pipe
the LSR leaves the exposed header "as is"). Mode (necessarily without PHP).
2.6.3 Uniform Model 2.6.3 Uniform Model
With the Uniform Model, MPLS tunnels (aka LSPs) are viewed as With the Uniform Model, MPLS tunnels (aka LSPs) are viewed as
artifacts of the end-to-end path from the Diff-Serv standpoint. MPLS artifacts of the end-to-end path from the Diff-Serv standpoint. MPLS
Tunnels may be used for forwarding purposes but have no significant Tunnels may be used for forwarding purposes but have no significant
impact on Diff-Serv. In this model, any packet contains exactly one impact on Diff-Serv. In this model, any packet contains exactly one
piece of Diff-Serv information which is meaningful and is always piece of Diff-Serv information which is meaningful and is always
encoded in the outer most label entry (or in the IP DSCP where the encoded in the outer most label entry (or in the IP DSCP where the
IP packet is transmitted unlabelled for instance at the egress of IP packet is transmitted unlabelled for instance at the egress of
skipping to change at line 767 skipping to change at line 857
meaningful at the egress of the LSP. meaningful at the egress of the LSP.
Operation of the Uniform Model without PHP is illustrated below: Operation of the Uniform Model without PHP is illustrated below:
========== LSP =============================> ========== LSP =============================>
---Swap--(M)--...-Swap--(M)--Swap---- ---Swap--(M)--...-Swap--(M)--Swap----
/ (outer header) \ / (outer header) \
(M) (M) (M) (M)
/ \ / \
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>--(M)--Push...............(x).......................Pop--(M)-> >--(M)--Push...............(x).......................Pop--(M)->
I (inner header) E I (inner header) E
(M) represents the Meaningful Diff-Serv information encoded in the (M) represents the Meaningful Diff-Serv information encoded in the
corresponding header. corresponding header.
(x) represents non-meaningful Diff-Serv information. (x) represents non-meaningful Diff-Serv information.
I represents the LSP ingress node I represents the LSP ingress node
E represents the LSP egress node E represents the LSP egress node
Operation of the Uniform Model with PHP is illustrated below : Operation of the Uniform Model with PHP is illustrated below :
========== LSP =========================> ========== LSP =========================>
---Swap-(M)-...-Swap------ ---Swap-(M)-...-Swap------
/ (outer header) \ / (outer header) \
(M) (M) (M) (M)
/ \ / \
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>--(M)--Push..............(x)............Pop-(M)--E--(M)-> >--(M)--Push..............(x)............Pop-(M)--E--(M)->
I (inner header) P I (inner header) P
(M) represents the Meaningful Diff-Serv information encoded in the (M) represents the Meaningful Diff-Serv information encoded in the
corresponding header. corresponding header.
(x) represents non-meaningful Diff-Serv information. (x) represents non-meaningful Diff-Serv information.
I represents the LSP ingress node I represents the LSP ingress node
P represents the LSP penultimate node P represents the LSP penultimate node
E represents the LSP egress node E represents the LSP egress node
skipping to change at line 820 skipping to change at line 910
The Uniform Model MAY be supported. The Uniform Model MAY be supported.
For support of the Uniform Model over a given LSP, an LSR performs For support of the Uniform Model over a given LSP, an LSR performs
Incoming PHB Determination and Diff-Serv information Encoding in the Incoming PHB Determination and Diff-Serv information Encoding in the
following manner: following manner:
- when receiving an unlabelled packet, the LSR performs Incoming - when receiving an unlabelled packet, the LSR performs Incoming
PHB Determination considering the received IP Header. PHB Determination considering the received IP Header.
- when receiving a labeled packet, the LSR performs Incoming PHB - when receiving a labeled packet, the LSR performs Incoming PHB
Determination considering the outer label entry in the received Determination considering the outer label entry in the received
label stack. In particular, when a pop operation is to be label stack. In particular, when a pop operation is to be
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MPLS Support of Diff-Serv August 2000
performed for the considered LSP, the LSR performs Incoming PHB performed for the considered LSP, the LSR performs Incoming PHB
Determination BEFORE the pop. Determination BEFORE the pop.
- when performing a push operation for the considered LSP, the LSR - when performing a push operation for the considered LSP, the LSR
encodes Diff-Serv Information in the transmitted label entry encodes Diff-Serv Information in the transmitted label entry
corresponding to the pushed label. The Diff-Serv Information corresponding to the pushed label. The Diff-Serv Information
encoded in the encapsulated header (swapped label entry or IP encoded in the encapsulated header (swapped label entry or IP
Header) is of no importance. Header) is of no importance.
- when performing a swap-only operation for the considered LSP, - when performing a swap-only operation for the considered LSP,
the LSR encodes Diff-Serv Information in the transmitted label the LSR encodes Diff-Serv Information in the transmitted label
entry corresponding to the swapped label. entry that contains the swapped label.
- when PHP is used, the Penultimate LSR needs to be aware of the - when PHP is used, the Penultimate LSR needs to be aware of the
"Set of PHB-->Encaps mappings" for the label corresponding to "Set of PHB-->Encaps mappings" for the label corresponding to
the exposed header (or the PHB-->DSCP mapping) in order to the exposed header (or the PHB-->DSCP mapping) in order to
perform Diff-Serv Information Encoding. Methods for providing perform Diff-Serv Information Encoding. Methods for providing
this mapping awareness are outside the scope of this this mapping awareness are outside the scope of this
specification. As an example, the "PHB-->DSCP mapping" may be specification. As an example, the "PHB-->DSCP mapping" may be
locally configured. As another example, in some environments, it locally configured. As another example, in some environments, it
may be appropriate for the Penultimate LSR to assume that the may be appropriate for the Penultimate LSR to assume that the
"Set of PHB-->Encaps mappings" to be used for the outgoing label "Set of PHB-->Encaps mappings" to be used for the outgoing label
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MPLS Support of Diff-Serv February 2001
in the exposed header is the "Set of PHB-->Encaps mappings" that in the exposed header is the "Set of PHB-->Encaps mappings" that
would be used by the LSR if the LSR was not doing PHP. would be used by the LSR if the LSR was not doing PHP.
Note also that this specification assumes that the Penultimate Note also that this specification assumes that the Penultimate
LSR does not perform label swapping over the label entry exposed LSR does not perform label swapping over the label entry exposed
by the pop operation (and in fact that it does not even look at by the pop operation (and in fact that it does not even look at
the exposed label). Consequently, restrictions may apply to the the exposed label). Consequently, restrictions may apply to the
Diff-Serv Information Encoding that can be performed by the Diff-Serv Information Encoding that can be performed by the
Penultimate LSR. For example, this specification does not allow Penultimate LSR. For example, this specification does not allow
situations where the Penultimate LSR pops a label corresponding situations where the Penultimate LSR pops a label corresponding
to an E-LSP supporting two PSCs, while the header exposed by the to an E-LSP supporting two PSCs, while the header exposed by the
pop contains label values for two L-LSPs each supporting one pop contains label values for two L-LSPs each supporting one
PSC, since the Diff-Serv Information Encoding would require PSC, since the Diff-Serv Information Encoding would require
selecting one label or the other. selecting one label or the other.
Note that LSR behaviors for the Pipe Model and for the Uniform Model Note that LSR behaviors for the Pipe , the Short Pipe and the
only differ when doing a push or a pop. Thus, Intermediate LSRs Uniform Model only differ when doing a push or a pop. Thus,
which perform swap only operations for an LSP , behave exactly in Intermediate LSRs which perform swap only operations for an LSP,
the same way regardless of whether they are behaving in the Pipe behave exactly in the same way regardless of whether they are
Model or the Uniform model. With a Diff-Serv implementation behaving in the Pipe, Short Pipe or the Uniform model. With a Diff-
supporting both the Pipe Model and the Uniform Model, only LSRs Serv implementation supporting multiple Tunneling Models, only LSRs
behaving as LSP Ingress, Penultimate LSR or LSP Egress need to be behaving as LSP Ingress, Penultimate LSR or LSP Egress need to be
configured to operate in a particular Model. Signaling to associate configured to operate in a particular Model. Signaling to associate
a Diff-Serv tunneling model on a per-LSP basis is out of the scope a Diff-Serv tunneling model on a per-LSP basis is out of the scope
of this specification. of this specification.
2.6.4 Hierarchy 2.6.4 Hierarchy
Through the label stack mechanism, MPLS allows LSP tunneling to nest Through the label stack mechanism, MPLS allows LSP tunneling to nest
to any depth. We observe that with such nesting, the push of level to any depth. We observe that with such nesting, the push of level
N+1 takes place on a subsequent (or the same) LSR to the LSR doing N+1 takes place on a subsequent (or the same) LSR to the LSR doing
the push for level N, while the pop of level N+1 takes place on a the push for level N, while the pop of level N+1 takes place on a
previous (or the same) LSR to the LSR doing the pop of level N. For previous (or the same) LSR to the LSR doing the pop of level N. For
a given level N LSP, the Ingress LSR doing the push and the LSR a given level N LSP, the Ingress LSR doing the push and the LSR
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MPLS Support of Diff-Serv August 2000
doing the pop (Penultimate LSR or LSP Egress) must operate in the doing the pop (Penultimate LSR or LSP Egress) must operate in the
same Tunneling Model (i.e. Pipe or Uniform). However, there is no same Tunneling Model (i.e. Pipe, Short Pipe or Uniform). However,
requirement for consistent tunneling models across levels so that there is no requirement for consistent tunneling models across
LSPs at different levels may be operating in different Tunneling levels so that LSPs at different levels may be operating in
Models. different Tunneling Models.
Hierarchical operations is illustrated below in the case of two Hierarchical operations is illustrated below in the case of two
levels of tunnels: levels of tunnels:
+--------Swap--...---+ +--------Swap--...---+
/ (outmost header) \ / (outmost header) \
/ \ / \
Push(2).................(2)Pop Push(2).................(2)Pop
/ (outer header) \ / (outer header) \
/ \ / \
>>---Push(1)........................(1)Pop-->> >>---Push(1)........................(1)Pop-->>
(inner header) (inner header)
(1) Tunneling Model 1 (1) Tunneling Model 1
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(2) Tunneling Model 2 (2) Tunneling Model 2
Tunneling Model 2 may be the same as or may be different to Tunneling Model 2 may be the same as or may be different to
Tunneling Model 1. Tunneling Model 1.
For support of M levels of push in the Pipe Model: For a given LSP of level N, the LSR must perform the Incoming PHB
- when performing multiple push operations, the LSR: Determination and the Diff-Serv information Encoding as specified in
o encodes Diff-Serv Information corresponding to the section 2.6.2, 2.6.2.1 and 2.6.3 according to the Tunneling Model of
Outgoing PHB in the transmitted label entry corresponding this level N LSP and independently of the Tunneling Model of other
to the LAST pushed label (i.e. the label pushed in the level LSPs.
outer label entry).
o encodes Diff-Serv Information corresponding to the
Incoming PHB in the encapsulated header (swapped label
entry or IP header) as well as in the label entries for
all the pushed labels (except the last pushed label).
For support of M levels of pop in the Pipe Model:
- when performing multiple pop operations for an LSP, the LSR
performs Incoming PHB Determination considering the header
(label entry or IP header) which is used to do the actual
forwarding. In other words, when a pop operation is to be
performed for the considered LSP, the LSR performs Incoming PHB
Determination AFTER ALL the pop operations.
For support of M levels of push in the Uniform Model:
- when performing multiple push operations, the LSR encodes Diff-
Serv Information in the transmitted label entry corresponding to
the LAST pushed label (i.e. the label pushed in the outer label
entry). The Diff-Serv Information encoded in the encapsulated
header (swapped label entry or IP Header) as well as the Diff-
Serv Information encoded in label entries for other pushed
labels are of no importance.
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For support of M levels of pop in the Uniform Model:
- when performing multiple pop operations for an LSP, the LSR
performs Incoming PHB Determination considering the outmost
label entry in the received label stack. In other words, when
multiple pop operations are to be performed, the LSR performs
Incoming PHB Determination BEFORE ANY pop operations.
3. Detailed Operations of E-LSPs 3. Detailed Operations of E-LSPs
3.1 E-LSP Definition 3.1 E-LSP Definition
E-LSPs are defined in section 1.2. E-LSPs are defined in section 1.2.
Within a given MPLS Diff-Serv domain, all the E-LSPs relying on the Within a given MPLS Diff-Serv domain, all the E-LSPs relying on the
pre-configured mapping are capable of transporting the same common pre-configured mapping are capable of transporting the same common
set of 8, or fewer, BAs. Each of those E-LSPs may actually transport set of 8, or fewer, BAs. Each of those E-LSPs may actually transport
skipping to change at line 980 skipping to change at line 1038
has been explicitly signaled at LSP setup, the `EXP-->PHB mapping' has been explicitly signaled at LSP setup, the `EXP-->PHB mapping'
is populated as per the signaled EXP<-->PHB mapping. is populated as per the signaled EXP<-->PHB mapping.
3.2.1 Preconfigured EXP<-->PHB mapping 3.2.1 Preconfigured EXP<-->PHB mapping
LSRs supporting E-LSPs which use the preconfigured EXP<-->PHB LSRs supporting E-LSPs which use the preconfigured EXP<-->PHB
mapping must allow local configuration of this EXP<-->PHB mapping. mapping must allow local configuration of this EXP<-->PHB mapping.
This mapping applies to all the E-LSPs established on this LSR This mapping applies to all the E-LSPs established on this LSR
without a mapping explicitly signaled at set-up time. without a mapping explicitly signaled at set-up time.
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The preconfigured EXP<-->PHB mapping must either be consistent at The preconfigured EXP<-->PHB mapping must either be consistent at
every E-LSP hop throughout the MPLS Diff-Serv domain spanned by the every E-LSP hop throughout the MPLS Diff-Serv domain spanned by the
LSP or appropriate remarking of the EXP field must be performed by LSP or appropriate remarking of the EXP field must be performed by
the LSR whenever a different preconfigured mapping is used on the the LSR whenever a different preconfigured mapping is used on the
ingress and egress interfaces. ingress and egress interfaces.
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In case, the preconfigured EXP<-->PHB mapping has not actually been In case, the preconfigured EXP<-->PHB mapping has not actually been
configured by the Network Administrator, the LSR should use a configured by the Network Administrator, the LSR should use a
default preconfigured EXP<-->PHB mapping which maps all EXP values default preconfigured EXP<-->PHB mapping which maps all EXP values
to the Default PHB. to the Default PHB.
3.3 Incoming PHB Determination On Incoming E-LSP 3.3 Incoming PHB Determination On Incoming E-LSP
This section defines how Incoming PHB Determination is carried out This section defines how Incoming PHB Determination is carried out
when the considered label entry in the received label stack when the considered label entry in the received label stack
corresponds to an E-LSP. This requires that the `Encaps-->PHB corresponds to an E-LSP. This requires that the `Encaps-->PHB
skipping to change at line 1034 skipping to change at line 1092
discussed above in section 3.2.1. discussed above in section 3.2.1.
If the label corresponds to an E-LSP for which an EXP<-->PHB mapping If the label corresponds to an E-LSP for which an EXP<-->PHB mapping
has been explicitly signaled at LSP setup, the `PHB-->EXP mapping' has been explicitly signaled at LSP setup, the `PHB-->EXP mapping'
is populated as per the signaled EXP<-->PHB mapping. is populated as per the signaled EXP<-->PHB mapping.
3.4.2 `PHB-->CLP mapping' 3.4.2 `PHB-->CLP mapping'
If the LSP is egressing over an ATM interface which is not label If the LSP is egressing over an ATM interface which is not label
switching controlled, then one `PHB-->CLP mapping' is added to the switching controlled, then one `PHB-->CLP mapping' is added to the
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`Set of PHB-->Encaps mappings' for this outgoing LSP. This `Set of PHB-->Encaps mappings' for this outgoing LSP. This
`PHB-->CLP mapping' is populated in the following way: `PHB-->CLP mapping' is populated in the following way:
- it is a function of the PHBs supported on this LSP, and may use - it is a function of the PHBs supported on this LSP, and may use
the relevant mapping entries for these PHBs from the the relevant mapping entries for these PHBs from the
Default PHB-->CLP Mapping defined in section 3.4.2.1. Other Default PHB-->CLP Mapping defined in section 3.4.2.1. Other
mappings than the one defined in section 3.4.2.1 may be used. In mappings than the one defined in section 3.4.2.1 may be used. In
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MPLS Support of Diff-Serv August 2000
particular, if a mapping from PHBs to CLP is standardized in the particular, if a mapping from PHBs to CLP is standardized in the
future for operations of Diff-Serv over ATM, such standardized future for operations of Diff-Serv over ATM, such standardized
mapping may then be used. mapping may then be used.
For example if the outgoing label corresponds to an LSP supporting For example if the outgoing label corresponds to an LSP supporting
the AF1 PSC , then the `PHB-->CLP mapping' may be populated with: the AF1 PSC , then the `PHB-->CLP mapping' may be populated with:
PHB CLP Field PHB CLP Field
AF11 ----> 0 AF11 ----> 0
skipping to change at line 1091 skipping to change at line 1149
the one defined in section 3.4.3.1 may be used. In particular, the one defined in section 3.4.3.1 may be used. In particular,
if a mapping from PHBs to DE is standardized in the future for if a mapping from PHBs to DE is standardized in the future for
operations of Diff-Serv over Frame Relay, such standardized operations of Diff-Serv over Frame Relay, such standardized
mapping may then be used. mapping may then be used.
Notice that in this case the `Set of PHB-->Encaps mappings' contains Notice that in this case the `Set of PHB-->Encaps mappings' contains
both a `PHB-->EXP mapping' and a `PHB-->DE mapping'. both a `PHB-->EXP mapping' and a `PHB-->DE mapping'.
3.4.3.1 Default PHB-->DE Mapping 3.4.3.1 Default PHB-->DE Mapping
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PHB DE Bit PHB DE Bit
DF ----> 0 DF ----> 0
CSn ----> 0 CSn ----> 0
AFn1 ----> 0 AFn1 ----> 0
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AFn2 ----> 1 AFn2 ----> 1
AFn3 ----> 1 AFn3 ----> 1
EF ----> 0 EF ----> 0
3.4.4 `PHB-->802.1 mapping' 3.4.4 `PHB-->802.1 mapping'
If the LSP is egressing over a LAN interface on which multiple 802.1 If the LSP is egressing over a LAN interface on which multiple 802.1
Traffic Classes are supported as per [IEEE_802.1], then one Traffic Classes are supported as per [IEEE_802.1], then one
`PHB-->802.1 mapping' is added to the `Set of PHB-->Encaps mappings' `PHB-->802.1 mapping' is added to the `Set of PHB-->Encaps mappings'
for this outgoing LSP. This `PHB-->802.1 mapping' is populated in for this outgoing LSP. This `PHB-->802.1 mapping' is populated in
skipping to change at line 1147 skipping to change at line 1204
NHLFE. NHLFE.
3.5.1 `PHB-->EXP mapping' 3.5.1 `PHB-->EXP mapping'
If the `Set of PHB-->Encaps mappings' contains a mapping of the form If the `Set of PHB-->Encaps mappings' contains a mapping of the form
`PHB-->EXP mapping', then the LSR: `PHB-->EXP mapping', then the LSR:
- determines the value to be written in the EXP field of the - determines the value to be written in the EXP field of the
corresponding level label entry by looking up the "outgoing PHB" corresponding level label entry by looking up the "outgoing PHB"
in this PHB-->EXP mapping table. in this PHB-->EXP mapping table.
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3.5.2 `PHB-->CLP mapping' 3.5.2 `PHB-->CLP mapping'
If the `Set of PHB-->Encaps mappings' contains a mapping of the form If the `Set of PHB-->Encaps mappings' contains a mapping of the form
`PHB-->CLP mapping', then the LSR: `PHB-->CLP mapping', then the LSR:
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- determines the value to be written in the CLP field of the ATM - determines the value to be written in the CLP field of the ATM
encapsulation header, by looking up the "outgoing PHB" in this encapsulation header, by looking up the "outgoing PHB" in this
PHB-->CLP mapping table. PHB-->CLP mapping table.
3.5.3 `PHB-->DE mapping' 3.5.3 `PHB-->DE mapping'
If the `Set of PHB-->Encaps mappings' contains a mapping of the form If the `Set of PHB-->Encaps mappings' contains a mapping of the form
`PHB-->DE mapping', then the LSR: `PHB-->DE mapping', then the LSR:
- determines the value to be written in the DE field of the Frame - determines the value to be written in the DE field of the Frame
Relay encapsulation header, by looking up the "outgoing PHB" in Relay encapsulation header, by looking up the "outgoing PHB" in
skipping to change at line 1201 skipping to change at line 1257
PHBs supported over an E-LSP is not signaled at establishment time, PHBs supported over an E-LSP is not signaled at establishment time,
an LSR can not rely on signaling information to enforce the above an LSR can not rely on signaling information to enforce the above
merge. However all E-LSPs using the preconfigured EXP<-->PHB mapping merge. However all E-LSPs using the preconfigured EXP<-->PHB mapping
are required to support the same set of Behavior Aggregates within a are required to support the same set of Behavior Aggregates within a
given MPLS Diff-Serv domain. Thus, merging of E-LSPs using the given MPLS Diff-Serv domain. Thus, merging of E-LSPs using the
preconfigured EXP<-->PHB mapping is allowed within a given MPLS preconfigured EXP<-->PHB mapping is allowed within a given MPLS
Diff-Serv domain. Diff-Serv domain.
4. Detailed Operation of L-LSPs 4. Detailed Operation of L-LSPs
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4.1 L-LSP Definition 4.1 L-LSP Definition
L-LSPs are defined in section 1.3. L-LSPs are defined in section 1.3.
4.2 Populating the `Encaps-->PHB mapping' for an incoming L-LSP 4.2 Populating the `Encaps-->PHB mapping' for an incoming L-LSP
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This section defines how the `Encaps-->PHB mapping' of the Diff-Serv This section defines how the `Encaps-->PHB mapping' of the Diff-Serv
Context is populated at label setup for an incoming L-LSP in order Context is populated at label setup for an incoming L-LSP in order
to allow Incoming PHB determination. to allow Incoming PHB determination.
4.2.1 `EXP-->PHB mapping' 4.2.1 `EXP-->PHB mapping'
If the LSR terminates the MPLS Shim Layer over this incoming L-LSP If the LSR terminates the MPLS Shim Layer over this incoming L-LSP
and the L-LSP ingresses on an interface which is not ATM nor Frame and the L-LSP ingresses on an interface which is not ATM nor Frame
Relay, then the `Encaps-->PHB mapping' is populated in the following Relay, then the `Encaps-->PHB mapping' is populated in the following
way: way:
skipping to change at line 1232 skipping to change at line 1288
LSP, and must use the relevant mapping entries for this PSC from LSP, and must use the relevant mapping entries for this PSC from
the Mandatory EXP/PSC-->PHB Mapping defined in Section 4.2.1.1. the Mandatory EXP/PSC-->PHB Mapping defined in Section 4.2.1.1.
For example if the incoming label corresponds to an L-LSP supporting For example if the incoming label corresponds to an L-LSP supporting
the AF1 PSC, then the `Encaps-->PHB mapping' will be populated with: the AF1 PSC, then the `Encaps-->PHB mapping' will be populated with:
EXP Field PHB EXP Field PHB
000 ----> AF11 000 ----> AF11
001 ----> AF12 001 ----> AF12
010 ----> AF13 011 ----> AF13
An LSR supporting L-LSPs over PPP interfaces and LAN interfaces is An LSR supporting L-LSPs over PPP interfaces and LAN interfaces is
an example of LSR terminating the Shim layer over ingress interfaces an example of LSR terminating the Shim layer over ingress interfaces
which are not ATM nor Frame Relay. which are not ATM nor Frame Relay.
If the LSR terminates the MPLS Shim Layer over this incoming L-LSP If the LSR terminates the MPLS Shim Layer over this incoming L-LSP
and the L-LSP ingresses on an ATM or Frame Relay interface, then the and the L-LSP ingresses on an ATM or Frame Relay interface, then the
`Encaps-->PHB mapping' is populated in the following way: `Encaps-->PHB mapping' is populated in the following way:
- it should actually be a `EXP-->PHB mapping'. Alternative - it should actually be a `EXP-->PHB mapping'. Alternative
optional ways of populating the `Encaps-->PHB mapping' might be optional ways of populating the `Encaps-->PHB mapping' might be
skipping to change at line 1256 skipping to change at line 1312
- when the `Encaps-->PHB mapping' is an `EXP-->PHB mapping', this - when the `Encaps-->PHB mapping' is an `EXP-->PHB mapping', this
`EXP-->PHB mapping' mapping is a function of the PSC which is `EXP-->PHB mapping' mapping is a function of the PSC which is
carried on the L-LSP, and must use the relevant mapping entries carried on the L-LSP, and must use the relevant mapping entries
for this PSC from the Mandatory EXP/PSC-->PHB Mapping defined in for this PSC from the Mandatory EXP/PSC-->PHB Mapping defined in
Section 4.2.1.1. Section 4.2.1.1.
An Edge-LSR of an ATM-MPLS domain or of a FR-MPLS domain is an An Edge-LSR of an ATM-MPLS domain or of a FR-MPLS domain is an
example of LSR terminating the shim layer over an ingress ATM/FR example of LSR terminating the shim layer over an ingress ATM/FR
interface. interface.
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MPLS Support of Diff-Serv February 2001
4.2.1.1 Mandatory EXP/PSC --> PHB mapping 4.2.1.1 Mandatory EXP/PSC --> PHB mapping
EXP Field PSC PHB EXP Field PSC PHB
000 DF ----> DF 000 DF ----> DF
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MPLS Support of Diff-Serv August 2000
000 CSn ----> CSn 000 CSn ----> CSn
000 AFn ----> AFn1 000 AFn ----> AFn1
001 AFn ----> AFn2 001 AFn ----> AFn2
010 AFn ----> AFn3 011 AFn ----> AFn3
000 EF ----> EF 000 EF ----> EF
4.2.2 `CLP-->PHB mapping' 4.2.2 `CLP-->PHB mapping'
If the LSR does not terminate an MPLS Shim Layer over this incoming If the LSR does not terminate an MPLS Shim Layer over this incoming
label and uses ATM encapsulation (i.e. it is an ATM-LSR), then the label and uses ATM encapsulation (i.e. it is an ATM-LSR), then the
`Encaps-->PHB mapping' for this incoming L-LSP is populated in the `Encaps-->PHB mapping' for this incoming L-LSP is populated in the
following way: following way:
- it is actually a `CLP-->PHB mapping' - it is actually a `CLP-->PHB mapping'
- the mapping is a function of the PSC which is carried on this - the mapping is a function of the PSC which is carried on this
skipping to change at line 1311 skipping to change at line 1366
4.2.3 `DE-->PHB mapping' 4.2.3 `DE-->PHB mapping'
If the LSR does not terminate an MPLS Shim Layer over this incoming If the LSR does not terminate an MPLS Shim Layer over this incoming
label and uses Frame Relay encapsulation (i.e. it is a FR-LSR), then label and uses Frame Relay encapsulation (i.e. it is a FR-LSR), then
the `Encaps-->PHB mapping' for this incoming L-LSP is populated in the `Encaps-->PHB mapping' for this incoming L-LSP is populated in
the following way: the following way:
- it is actually a `DE-->PHB mapping' - it is actually a `DE-->PHB mapping'
- the mapping is a function of the PSC which is carried on this - the mapping is a function of the PSC which is carried on this
LSP, and should use the relevant mapping entries for this PSC LSP, and should use the relevant mapping entries for this PSC
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MPLS Support of Diff-Serv February 2001
from the Default DE/PSC-->PHB Mapping defined in Section from the Default DE/PSC-->PHB Mapping defined in Section
4.2.3.1. 4.2.3.1.
4.2.3.1 Default DE/PSC --> PHB Mapping 4.2.3.1 Default DE/PSC --> PHB Mapping
DE Bit PSC PHB DE Bit PSC PHB
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MPLS Support of Diff-Serv August 2000
0 DF ----> DF 0 DF ----> DF
0 CSn ----> CSn 0 CSn ----> CSn
0 AFn ----> AFn1 0 AFn ----> AFn1
1 AFn ----> AFn2 1 AFn ----> AFn2
0 EF ----> EF 0 EF ----> EF
4.3 Incoming PHB Determination On Incoming L-LSP 4.3 Incoming PHB Determination On Incoming L-LSP
This section defines how Incoming PHB determination is carried out This section defines how Incoming PHB determination is carried out
when the considered label entry in the received label stack when the considered label entry in the received label stack
skipping to change at line 1367 skipping to change at line 1423
Frame Relay encapsulation and by using the DE-->PHB mapping. Frame Relay encapsulation and by using the DE-->PHB mapping.
4.4 Populating the `Set of PHB-->Encaps mappings' for an outgoing L-LSP 4.4 Populating the `Set of PHB-->Encaps mappings' for an outgoing L-LSP
This section defines how the `Set of PHB-->Encaps mappings' of the This section defines how the `Set of PHB-->Encaps mappings' of the
Diff-Serv Context is populated at label setup for an outgoing L-LSP Diff-Serv Context is populated at label setup for an outgoing L-LSP
in order to allow Encoding of Diff-Serv Information. in order to allow Encoding of Diff-Serv Information.
4.4.1 `PHB-->EXP mapping' 4.4.1 `PHB-->EXP mapping'
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MPLS Support of Diff-Serv February 2001
If the LSR uses an MPLS Shim Layer over this outgoing L-LSP, then If the LSR uses an MPLS Shim Layer over this outgoing L-LSP, then
one `PHB-->EXP mapping' is added to the `Set of one `PHB-->EXP mapping' is added to the `Set of
PHB-->Encaps mappings' for this outgoing PHB-->Encaps mappings' for this outgoing
L-LSP. This `PHB-->EXP mapping' is populated in the following way: L-LSP. This `PHB-->EXP mapping' is populated in the following way:
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MPLS Support of Diff-Serv August 2000
- it is a function of the PSC supported on this LSP, and must use - it is a function of the PSC supported on this LSP, and must use
the mapping entries relevant for this PSC from the Mandatory the mapping entries relevant for this PSC from the Mandatory
PHB-->EXP Mapping defined in section 4.4.1.1. PHB-->EXP Mapping defined in section 4.4.1.1.
For example if the outgoing label corresponds to an L-LSP supporting For example if the outgoing label corresponds to an L-LSP supporting
the AF1 PSC, then the following `PHB-->EXP mapping' is added into the AF1 PSC, then the following `PHB-->EXP mapping' is added into
the `Set of PHB-->Encaps mappings': the `Set of PHB-->Encaps mappings':
PHB EXP Field PHB EXP Field
AF11 ----> 000 AF11 ----> 000
AF12 ----> 001 AF12 ----> 001
AF13 ----> 010 AF13 ----> 011
4.4.1.1 Mandatory PHB-->EXP Mapping 4.4.1.1 Mandatory PHB-->EXP Mapping
PHB EXP Field PHB EXP Field
DF ----> 000 DF ----> 000
CSn ----> 000 CSn ----> 000
AFn1 ----> 000 AFn1 ----> 000
AFn2 ----> 001 AFn2 ----> 001
AFn3 ----> 010 AFn3 ----> 011
EF ----> 000 EF ----> 000
4.4.2 `PHB-->CLP mapping' 4.4.2 `PHB-->CLP mapping'
If the L-LSP is egressing on an ATM interface (i.e. it is an ATM-LSR If the L-LSP is egressing on an ATM interface (i.e. it is an ATM-LSR
or it is a frame-based LSR sending packets on an LC-ATM interface or or it is a frame-based LSR sending packets on an LC-ATM interface or
on an ATM interface which is not label switching controlled), then on an ATM interface which is not label switching controlled), then
one `PHB-->CLP mapping' is added to the `Set of PHB-->Encaps one `PHB-->CLP mapping' is added to the `Set of PHB-->Encaps
mappings' for this outgoing L-LSP. mappings' for this outgoing L-LSP.
skipping to change at line 1421 skipping to change at line 1476
If the L-LSP is egressing over an LC-ATM interface, the `PHB-->CLP If the L-LSP is egressing over an LC-ATM interface, the `PHB-->CLP
mapping' is populated in the following way: mapping' is populated in the following way:
- it is a function of the PSC supported on this LSP, and should - it is a function of the PSC supported on this LSP, and should
use the relevant mapping entries for this PSC from the Default use the relevant mapping entries for this PSC from the Default
PHB-->CLP Mapping defined in section 3.4.2.1. PHB-->CLP Mapping defined in section 3.4.2.1.
Notice that if the LSR is a frame-based LSR supporting an L-LSP Notice that if the LSR is a frame-based LSR supporting an L-LSP
egressing over an ATM interface, then the `Set of PHB-->Encaps egressing over an ATM interface, then the `Set of PHB-->Encaps
mappings' contains both a `PHB-->EXP mapping' and a `PHB-->CLP mappings' contains both a `PHB-->EXP mapping' and a `PHB-->CLP
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MPLS Support of Diff-Serv February 2001
mapping'. If the LSR is an ATM-LSR supporting an L-LSP, then the mapping'. If the LSR is an ATM-LSR supporting an L-LSP, then the
`Set of PHB-->Encaps mappings' only contains a `PHB-->CLP mapping'. `Set of PHB-->Encaps mappings' only contains a `PHB-->CLP mapping'.
4.4.3 `PHB-->DE mapping' 4.4.3 `PHB-->DE mapping'
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MPLS Support of Diff-Serv August 2000
If the L-LSP is egressing over a Frame Relay interface (i.e. it is If the L-LSP is egressing over a Frame Relay interface (i.e. it is
an LSR sending packets on an LC-FR interface or on a Frame Relay an LSR sending packets on an LC-FR interface or on a Frame Relay
interface which is not label switching controlled), one `PHB-->DE interface which is not label switching controlled), one `PHB-->DE
mapping' is added to the `Set of PHB-->Encaps mappings' for this mapping' is added to the `Set of PHB-->Encaps mappings' for this
outgoing L-LSP. outgoing L-LSP.
If the L-LSP is egressing over a FR interface which is not label If the L-LSP is egressing over a FR interface which is not label
switching controlled, the `PHB-->DE mapping' is populated as per switching controlled, the `PHB-->DE mapping' is populated as per
section 3.4.3. section 3.4.3.
skipping to change at line 1476 skipping to change at line 1532
Diff-Serv Context associated with the corresponding label in the Diff-Serv Context associated with the corresponding label in the
NHLFE and then performs corresponding encoding as specified in NHLFE and then performs corresponding encoding as specified in
sections 3.5.1, 3.5.2, 3.5.3 and 3.5.4. sections 3.5.1, 3.5.2, 3.5.3 and 3.5.4.
4.6 L-LSP Merging 4.6 L-LSP Merging
In an MPLS domain, two or more LSPs can be merged into one LSP at In an MPLS domain, two or more LSPs can be merged into one LSP at
one LSR. L-LSPs are compatible with LSP Merging under the following one LSR. L-LSPs are compatible with LSP Merging under the following
condition: condition:
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MPLS Support of Diff-Serv February 2001
L-LSPs can only be merged into one L-LSP if they support the L-LSPs can only be merged into one L-LSP if they support the
same PSC. same PSC.
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MPLS Support of Diff-Serv August 2000
The above merge condition MUST be enforced by LSRs through explicit The above merge condition MUST be enforced by LSRs through explicit
checking at label setup that the same PSC is supported on the merged checking at label setup that the same PSC is supported on the merged
LSPs. LSPs.
Note that when L-LSPs merge, the bandwidth that is available for the Note that when L-LSPs merge, the bandwidth that is available for the
PSC downstream of the merge point must be sufficient to carry the PSC downstream of the merge point must be sufficient to carry the
sum of the merged traffic. This is particularly important in the sum of the merged traffic. This is particularly important in the
case of EF traffic. This can be ensured in multiple ways (for case of EF traffic. This can be ensured in multiple ways (for
instance via provisioning, or via bandwidth signaling and explicit instance via provisioning, or via bandwidth signaling and explicit
admission control). admission control).
skipping to change at line 1530 skipping to change at line 1586
The DIFFSERV Object is optional for support of LSP Tunnels as The DIFFSERV Object is optional for support of LSP Tunnels as
defined in [RSVP_MPLS_TE]. A Diff-Serv capable LSR supporting E-LSPs defined in [RSVP_MPLS_TE]. A Diff-Serv capable LSR supporting E-LSPs
using the preconfigured EXP<-->PHB mapping in compliance with this using the preconfigured EXP<-->PHB mapping in compliance with this
specification MAY support the DIFFSERV Object. A Diff-Serv capable specification MAY support the DIFFSERV Object. A Diff-Serv capable
LSR supporting E-LSPs using a signaled EXP<-->PHB mapping in LSR supporting E-LSPs using a signaled EXP<-->PHB mapping in
compliance with this specification MUST support the DIFFSERV Object. compliance with this specification MUST support the DIFFSERV Object.
A Diff-Serv capable LSR supporting L-LSPs in compliance with this A Diff-Serv capable LSR supporting L-LSPs in compliance with this
specification MUST support the DIFFSERV Object. specification MUST support the DIFFSERV Object.
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MPLS Support of Diff-Serv February 2001
5.1.1 Path Message Format 5.1.1 Path Message Format
The format of the Path message is as follows: The format of the Path message is as follows:
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MPLS Support of Diff-Serv August 2000
<Path Message> ::= <Common Header> [ <INTEGRITY> ] <Path Message> ::= <Common Header> [ <INTEGRITY> ]
<SESSION> <RSVP_HOP> <SESSION> <RSVP_HOP>
<TIME_VALUES> <TIME_VALUES>
[ <EXPLICIT_ROUTE> ] [ <EXPLICIT_ROUTE> ]
<LABEL_REQUEST> <LABEL_REQUEST>
[ <SESSION_ATTRIBUTE> ] [ <SESSION_ATTRIBUTE> ]
[ <DIFFSERV> ] [ <DIFFSERV> ]
[ <POLICY_DATA> ... ] [ <POLICY_DATA> ... ]
[ <sender descriptor> ] [ <sender descriptor> ]
skipping to change at line 1585 skipping to change at line 1641
Reserved : 28 bits Reserved : 28 bits
This field is reserved. It must be set to zero on transmission This field is reserved. It must be set to zero on transmission
and must be ignored on receipt. and must be ignored on receipt.
MAPnb : 4 bits MAPnb : 4 bits
Indicates the number of MAP entries included in the DIFFSERV Indicates the number of MAP entries included in the DIFFSERV
Object. This can be set to any value from 0 to 8. Object. This can be set to any value from 0 to 8.
MAP : 32 bits MAP : 32 bits
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MPLS Support of Diff-Serv February 2001
Each MAP entry defines the mapping between one EXP field value Each MAP entry defines the mapping between one EXP field value
and one PHB. The MAP entry has the following format: and one PHB. The MAP entry has the following format:
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MPLS Support of Diff-Serv August 2000
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | EXP | PHBID | | Reserved | EXP | PHBID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Reserved : 13 bits Reserved : 13 bits
This field is reserved. It must be set to zero on This field is reserved. It must be set to zero on
transmission and must be ignored on receipt. transmission and must be ignored on receipt.
skipping to change at line 1640 skipping to change at line 1697
single PHB. It is the recommended DSCP value for that PHB, single PHB. It is the recommended DSCP value for that PHB,
left-justified in the 16-bit field, with bits 6 through 15 set left-justified in the 16-bit field, with bits 6 through 15 set
to zero. to zero.
- Where the PSC comprises multiple PHBs defined by standards - Where the PSC comprises multiple PHBs defined by standards
action, the PSC encoding is the encoding for this set of PHB. action, the PSC encoding is the encoding for this set of PHB.
It is the smallest numerical value of the recommended DSCP for It is the smallest numerical value of the recommended DSCP for
the various PHBs in the PSC, left-justified in the 16 bit the various PHBs in the PSC, left-justified in the 16 bit
field, with bits 6 through 13 and bit 15 set to zero and with field, with bits 6 through 13 and bit 15 set to zero and with
bit 14 set to one. bit 14 set to one.
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For instance, the encoding of the EF PSC is : For instance, the encoding of the EF PSC is :
0 1 0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
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MPLS Support of Diff-Serv August 2000
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1 0 1 1 1 0|0 0 0 0 0 0 0 0 0 0| |1 0 1 1 1 0|0 0 0 0 0 0 0 0 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
For instance, the encoding of the AF1 PSC is : For instance, the encoding of the AF1 PSC is :
0 1 0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 1 0 1 0|0 0 0 0 0 0 0 0 1 0| |0 0 1 0 1 0|0 0 0 0 0 0 0 0 1 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at line 1695 skipping to change at line 1751
message: message:
- with a session type of LSP_Tunnel_IPv4, - with a session type of LSP_Tunnel_IPv4,
- with the LABEL_REQUEST object, - with the LABEL_REQUEST object,
- with the DIFFSERV object for an L-LSP containing the PHB - with the DIFFSERV object for an L-LSP containing the PHB
Scheduling Class (PSC) supported on this L-LSP. Scheduling Class (PSC) supported on this L-LSP.
If a path message contains multiple DIFFSERV objects, only the first If a path message contains multiple DIFFSERV objects, only the first
one is meaningful; subsequent DIFFSERV object(s) must be ignored and one is meaningful; subsequent DIFFSERV object(s) must be ignored and
not forwarded. not forwarded.
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MPLS Support of Diff-Serv February 2001
Each LSR along the path records the DIFFSERV object, when present, Each LSR along the path records the DIFFSERV object, when present,
in its path state block. in its path state block.
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MPLS Support of Diff-Serv August 2000
If a DIFFSERV object is not present in the Path message, the LSR If a DIFFSERV object is not present in the Path message, the LSR
SHOULD interpret this as a request for an E-LSP using the SHOULD interpret this as a request for an E-LSP using the
Preconfigured EXP<-->PHB Mapping. However, for compatibility Preconfigured EXP<-->PHB Mapping. However, for backward
purposes with other non-Diff-Serv Quality of Service compatibility purposes with other non-Diff-Serv Quality of Service
options allowed by [RSVP_MPLS_TE] such as Integrated Services options allowed by [RSVP_MPLS_TE] such as Integrated Services
Controlled Load or Guaranteed Services, the LSR MAY support a Controlled Load or Guaranteed Services, the LSR MAY support a
configurable "override option". When this "override option" is configurable "override option". When this "override option" is
configured, the LSR interprets a path message without a Diff-Serv configured, the LSR interprets a path message without a Diff-Serv
object as a request for an LSP with such non-Diff-Serv Quality of object as a request for an LSP with such non-Diff-Serv Quality of
Service. Service.
If a DIFFSERV object for an E-LSP containing no MAP entry is present If a DIFFSERV object for an E-LSP containing no MAP entry is present
in the Path message, the LSR MUST interpret this as a request for an in the Path message, the LSR MUST interpret this as a request for an
E-LSP using the Preconfigured EXP<-->PHB Mapping. In particular, E-LSP using the Preconfigured EXP<-->PHB Mapping. In particular,
skipping to change at line 1750 skipping to change at line 1806
An LSR that recognizes the DIFFSERV object and that receives a path An LSR that recognizes the DIFFSERV object and that receives a path
message which contains the DIFFSERV object but which does not message which contains the DIFFSERV object but which does not
contain a LABEL_REQUEST object or which does not have a session type contain a LABEL_REQUEST object or which does not have a session type
of LSP_Tunnel_IPv4, sends a PathErr towards the sender with the of LSP_Tunnel_IPv4, sends a PathErr towards the sender with the
error code `Diff-Serv Error' and an error value of `Unexpected error code `Diff-Serv Error' and an error value of `Unexpected
DIFFSERV object'. Those are defined below in section 5.5. DIFFSERV object'. Those are defined below in section 5.5.
An LSR receiving a Path message with the DIFFSERV object for E-LSP, An LSR receiving a Path message with the DIFFSERV object for E-LSP,
which recognizes the DIFFSERV object but does not support the which recognizes the DIFFSERV object but does not support the
particular PHB encoded in one, or more, of the MAP entries, sends a particular PHB encoded in one, or more, of the MAP entries, sends a
Le Faucheur et. al 33
MPLS Support of Diff-Serv February 2001
PathErr towards the sender with the error code `Diff-Serv Error' and PathErr towards the sender with the error code `Diff-Serv Error' and
an error value of `Unsupported PHB'. Those are defined below in an error value of `Unsupported PHB'. Those are defined below in
section 5.5. section 5.5.
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MPLS Support of Diff-Serv August 2000
An LSR receiving a Path message with the DIFFSERV object for E-LSP, An LSR receiving a Path message with the DIFFSERV object for E-LSP,
which recognizes the DIFFSERV object but determines that the which recognizes the DIFFSERV object but determines that the
signaled EXP<-->PHB mapping is invalid, sends a PathErr towards the signaled EXP<-->PHB mapping is invalid, sends a PathErr towards the
sender with the error code `Diff-Serv Error' and an error value of sender with the error code `Diff-Serv Error' and an error value of
`Invalid EXP<-->PHB mapping'. Those are defined below in section `Invalid EXP<-->PHB mapping'. Those are defined below in section
5.5. The EXP<-->PHB mapping signaled in the DIFFSERV Object for an 5.5. The EXP<-->PHB mapping signaled in the DIFFSERV Object for an
E-LSP is invalid when: E-LSP is invalid when:
- the MAPnb field is not within the range 0 to 8 or - the MAPnb field is not within the range 0 to 8 or
- a given EXP value appears in more than one MAP entry, or - a given EXP value appears in more than one MAP entry, or
- the PHBID encoding is invalid. - the PHBID encoding is invalid.
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the procedures specified in [RSVP] for an unknown C-type i.e. It the procedures specified in [RSVP] for an unknown C-type i.e. It
must send a PathErr with the error code `Unknown object C-Type' must send a PathErr with the error code `Unknown object C-Type'
toward the sender. toward the sender.
In both situations, this causes the path set-up to fail. The sender In both situations, this causes the path set-up to fail. The sender
should notify management that a L-LSP cannot be established and should notify management that a L-LSP cannot be established and
possibly take action to retry LSP establishment without the DIFFSERV possibly take action to retry LSP establishment without the DIFFSERV
object (e.g. attempt to use E-LSPs with Preconfigured EXP<-->PHB object (e.g. attempt to use E-LSPs with Preconfigured EXP<-->PHB
mapping as a fall-back strategy). mapping as a fall-back strategy).
5.5 Error Codes For Diff-Serv Le Faucheur et. al 34
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Le Faucheur et. al 33 5.5 Error Codes For Diff-Serv
MPLS Support of Diff-Serv August 2000
In the procedures described above, certain errors must be reported In the procedures described above, certain errors must be reported
as a `Diff-Serv Error'. The value of the `Diff-Serv Error' error as a `Diff-Serv Error'. The value of the `Diff-Serv Error' error
code is TBD (number to be allocated by IANA)). code is TBD (number to be allocated by IANA)).
The following defines error values for the Diff-Serv Error: The following defines error values for the Diff-Serv Error:
Value Error Value Error
1 Unexpected DIFFSERV object 1 Unexpected DIFFSERV object
skipping to change at line 1861 skipping to change at line 1918
A Path message containing a COS SENDER_TSPEC and containing a A Path message containing a COS SENDER_TSPEC and containing a
DIFFSERV object for E-LSP indicates to a Diff-Serv capable LSR that DIFFSERV object for E-LSP indicates to a Diff-Serv capable LSR that
the LSP to be established is an E-LSP using a signaled mapping and the LSP to be established is an E-LSP using a signaled mapping and
without any bandwidth reservation. without any bandwidth reservation.
A Path message containing a COS SENDER_TSPEC and containing a A Path message containing a COS SENDER_TSPEC and containing a
DIFFSERV object for L-LSP indicates to a Diff-Serv capable LSR that DIFFSERV object for L-LSP indicates to a Diff-Serv capable LSR that
the LSP to be established is an L-LSP without any bandwidth the LSP to be established is an L-LSP without any bandwidth
reservation. reservation.
The above is summarized in the following table: Le Faucheur et. al 35
MPLS Support of Diff-Serv February 2001
Le Faucheur et. al 34 The above is summarized in the following table:
MPLS Support of Diff-Serv August 2000
Path Message LSP type Path Message LSP type
Service DIFFSERV Service DIFFSERV
Object Object
GS/CL No E-LSP + preconf mapping + bandw reservation GS/CL No E-LSP + preconf mapping + bandw reservation
GS/CL Yes/E-LSP E-LSP + signaled mapping + bandw reservation GS/CL Yes/E-LSP E-LSP + signaled mapping + bandw reservation
GS/CL Yes/L-LSP L-LSP + bandw reservation GS/CL Yes/L-LSP L-LSP + bandw reservation
COS No E-LSP + preconf mapping + no bandw reservation COS No E-LSP + preconf mapping + no bandw reservation
COS Yes/E-LSP E-LSP + signaled mapping + no band reservation COS Yes/E-LSP E-LSP + signaled mapping + no band reservation
skipping to change at line 1914 skipping to change at line 1971
uses the signaled EXP<-->PHB mapping in compliance with this uses the signaled EXP<-->PHB mapping in compliance with this
specification MUST support the Diff-Serv TLV. A Diff-Serv capable specification MUST support the Diff-Serv TLV. A Diff-Serv capable
LSR supporting L-LSPs in compliance with this specification MUST LSR supporting L-LSPs in compliance with this specification MUST
support the Diff-Serv TLV. support the Diff-Serv TLV.
6.1 Diff-Serv TLV 6.1 Diff-Serv TLV
The Diff-Serv TLV has the following formats: The Diff-Serv TLV has the following formats:
Diff-Serv TLV for an E-LSP: Diff-Serv TLV for an E-LSP:
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MPLS Support of Diff-Serv February 2001
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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MPLS Support of Diff-Serv August 2000
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| Diff-Serv (0x901) | Length | |U|F| Diff-Serv (0x901) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|T| Reserved | MAPnb | |T| Reserved | MAPnb |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAP (1) | | MAP (1) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
... ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at line 1969 skipping to change at line 2025
This field contains the value of the EXP field for the This field contains the value of the EXP field for the
EXP<-->PHB mapping defined in this MAP entry. EXP<-->PHB mapping defined in this MAP entry.
PHBID : 16 bits PHBID : 16 bits
This field contains the PHBID of the PHB for the This field contains the PHBID of the PHB for the
EXP<-->PHB mapping defined in this MAP entry. The PHBID EXP<-->PHB mapping defined in this MAP entry. The PHBID
is encoded as specified in section 2 of [PHBID]. is encoded as specified in section 2 of [PHBID].
Diff-Serv TLV for an L-LSP: Diff-Serv TLV for an L-LSP:
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0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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MPLS Support of Diff-Serv August 2000
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| Type = PSC (0x901) | Length | |U|F| Type = PSC (0x901) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|T| Reserved | PSC | |T| Reserved | PSC |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
T:1 bit T:1 bit
LSP Type. This is set to 1 for an L-LSP LSP Type. This is set to 1 for an L-LSP
Reserved : 15 bits Reserved : 15 bits
skipping to change at line 2025 skipping to change at line 2080
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
6.2 Diff-Serv Status Code Values 6.2 Diff-Serv Status Code Values
The following values are defined for the Status Code field of the The following values are defined for the Status Code field of the
Status TLV: Status TLV:
Status Code E Status Data Status Code E Status Data
Unexpected Diff-Serv TLV 0 0x01000001 Unexpected Diff-Serv TLV 0 0x01000001
Unsupported PHB 0 0x01000002
Invalid EXP<-->PHB mapping 0 0x01000003
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Unsupported PHB 0 0x01000002
Invalid EXP<-->PHB mapping 0 0x01000003
Unsupported PSC 0 0x01000004 Unsupported PSC 0 0x01000004
Per-LSP context allocation failure 0 0x01000005 Per-LSP context allocation failure 0 0x01000005
6.3 Diff-Serv Related LDP Messages 6.3 Diff-Serv Related LDP Messages
6.3.1 Label Request Message 6.3.1 Label Request Message
The format of the Label Request message is extended as follows, to The format of the Label Request message is extended as follows, to
optionally include the Diff-Serv TLV: optionally include the Diff-Serv TLV:
skipping to change at line 2081 skipping to change at line 2136
6.3.3 Label Release Message 6.3.3 Label Release Message
The format of the Label Release message is extended as follows, to The format of the Label Release message is extended as follows, to
optionally include the Status TLV: optionally include the Status TLV:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| Label Release (0x0403) | Message Length | |0| Label Release (0x0403) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FEC TLV | | FEC TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label TLV (optional) | | Label TLV (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status TLV (optional) | | Status TLV (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
6.3.4 Notification Message 6.3.4 Notification Message
The format of the Notification message is extended as follows, to The format of the Notification message is extended as follows, to
skipping to change at line 2138 skipping to change at line 2193
one MAP entry for each EXP value to be supported on this E-LSP. one MAP entry for each EXP value to be supported on this E-LSP.
When allocating a label for an L-LSP, a downstream Diff-Serv LSR When allocating a label for an L-LSP, a downstream Diff-Serv LSR
issues a Label Mapping message with the Diff-Serv TLV for an L-LSP issues a Label Mapping message with the Diff-Serv TLV for an L-LSP
which contains the PHB Scheduling Class (PSC) to be supported on which contains the PHB Scheduling Class (PSC) to be supported on
this L-LSP. this L-LSP.
Assuming the label set-up is successful, the downstream and upstream Assuming the label set-up is successful, the downstream and upstream
LSRs must: LSRs must:
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MPLS Support of Diff-Serv August 2000 MPLS Support of Diff-Serv February 2001
- update the Diff-Serv Context associated with the established - update the Diff-Serv Context associated with the established
LSPs in their ILM/FTN as specified in previous sections LSPs in their ILM/FTN as specified in previous sections
(incoming and outgoing label), (incoming and outgoing label),
- install the required Diff-Serv forwarding treatment (scheduling - install the required Diff-Serv forwarding treatment (scheduling
and dropping behavior) for this NHLFE (outgoing label). and dropping behavior) for this NHLFE (outgoing label).
An upstream Diff-Serv LSR receiving a Label Mapping message with An upstream Diff-Serv LSR receiving a Label Mapping message with
multiple Diff-Serv TLVs only considers the first one as meaningful. multiple Diff-Serv TLVs only considers the first one as meaningful.
The LSR must ignore and not forward the subsequent Diff-Serv TLV(s). The LSR must ignore and not forward the subsequent Diff-Serv TLV(s).
skipping to change at line 2193 skipping to change at line 2248
When requesting a label for an E-LSP which is to use a signaled When requesting a label for an E-LSP which is to use a signaled
EXP<-->PHB mapping, an upstream Diff-Serv LSR sends a Label Request EXP<-->PHB mapping, an upstream Diff-Serv LSR sends a Label Request
message with the Diff-Serv TLV for an E-LSP which contains one MAP message with the Diff-Serv TLV for an E-LSP which contains one MAP
entry for each EXP value to be supported on this E-LSP. entry for each EXP value to be supported on this E-LSP.
When requesting a label for an L-LSP, an upstream Diff-Serv LSR When requesting a label for an L-LSP, an upstream Diff-Serv LSR
sends a Label Request message with the Diff-Serv TLV for an L-LSP sends a Label Request message with the Diff-Serv TLV for an L-LSP
which contains the PSC to be supported on this L-LSP. which contains the PSC to be supported on this L-LSP.
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MPLS Support of Diff-Serv August 2000 MPLS Support of Diff-Serv February 2001
A downstream Diff-Serv LSR sending a Label Mapping message in A downstream Diff-Serv LSR sending a Label Mapping message in
response to a Label Request message for an E-LSP or an L-LSP must response to a Label Request message for an E-LSP or an L-LSP must
not include a Diff-Serv TLV in this Label Mapping message. not include a Diff-Serv TLV in this Label Mapping message.
Assuming the label set-up is successful, the downstream and upstream Assuming the label set-up is successful, the downstream and upstream
LSRs must: LSRs must:
- update the Diff-Serv Context associated with the established - update the Diff-Serv Context associated with the established
LSPs in their ILM/FTN as specified in previous sections LSPs in their ILM/FTN as specified in previous sections
(incoming and outgoing label), (incoming and outgoing label),
- install the required Diff-Serv forwarding treatment (scheduling - install the required Diff-Serv forwarding treatment (scheduling
skipping to change at line 2249 skipping to change at line 2304
A downstream Diff-Serv LSR that recognizes the Diff-Serv TLV Type in A downstream Diff-Serv LSR that recognizes the Diff-Serv TLV Type in
a Label Request message but is unable to allocate the required a Label Request message but is unable to allocate the required
per-LSP context information, must reject the request sending a per-LSP context information, must reject the request sending a
Notification message which includes the Status TLV with a Status Notification message which includes the Status TLV with a Status
Code of `Per-LSP context allocation failure'. Code of `Per-LSP context allocation failure'.
A downstream Diff-Serv LSR that recognizes the Diff-Serv TLV Type in A downstream Diff-Serv LSR that recognizes the Diff-Serv TLV Type in
a Label Request message and supports the requested PSC but is not a Label Request message and supports the requested PSC but is not
able to satisfy the label request for other reasons (e.g. no label able to satisfy the label request for other reasons (e.g. no label
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MPLS Support of Diff-Serv August 2000 MPLS Support of Diff-Serv February 2001
available), must send a Notification message in accordance with available), must send a Notification message in accordance with
existing LDP procedures [LDP] (e.g. with a `No Label Resource' existing LDP procedures [LDP] (e.g. with a `No Label Resource'
Status Code). This Notification message must include the requested Status Code). This Notification message must include the requested
Diff-Serv TLV. Diff-Serv TLV.
6.5 Non-Handling of the Diff-Serv TLV 6.5 Non-Handling of the Diff-Serv TLV
An LSR that does not recognize the Diff-Serv TLV Type, on receipt of An LSR that does not recognize the Diff-Serv TLV Type, on receipt of
a Label Request message or a Label Mapping message containing the a Label Request message or a Label Mapping message containing the
skipping to change at line 2301 skipping to change at line 2356
A Diff-Serv capable LSR MAY support E-LSPs which use signaled A Diff-Serv capable LSR MAY support E-LSPs which use signaled
EXP<-->PHB mapping and L-LSPs over these interfaces. EXP<-->PHB mapping and L-LSPs over these interfaces.
8. MPLS Support of Diff-Serv over LC-ATM Interfaces 8. MPLS Support of Diff-Serv over LC-ATM Interfaces
This section describes the specific operations required for MPLS This section describes the specific operations required for MPLS
support of Diff-Serv over label switching controlled ATM (LC-ATM) support of Diff-Serv over label switching controlled ATM (LC-ATM)
interfaces. interfaces.
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This document allows any number of L-LSPs per FEC within an MPLS ATM This document allows any number of L-LSPs per FEC within an MPLS ATM
Diff-Serv domain. E-LSPs are not supported over LC-ATM interfaces. Diff-Serv domain. E-LSPs are not supported over LC-ATM interfaces.
8.1 Use of ATM Traffic Classes and Traffic Management mechanisms 8.1 Use of ATM Traffic Classes and Traffic Management mechanisms
The use of the ATM traffic classes as specified by ITU-T and ATM- The use of the ATM traffic classes as specified by ITU-T and ATM-
Forum or of vendor specific ATM traffic classes is outside of the Forum or of vendor specific ATM traffic classes is outside of the
scope of this specification. The only requirement for compliant scope of this specification. The only requirement for compliant
implementation is that the forwarding behavior experienced by a implementation is that the forwarding behavior experienced by a
skipping to change at line 2356 skipping to change at line 2411
9.1 Use of Frame Relay Traffic parameters and Traffic Management 9.1 Use of Frame Relay Traffic parameters and Traffic Management
mechanisms mechanisms
The use of the Frame Relay traffic parameters as specified by ITU-T The use of the Frame Relay traffic parameters as specified by ITU-T
and Frame Relay-Forum or of vendor specific Frame Relay traffic and Frame Relay-Forum or of vendor specific Frame Relay traffic
management mechanisms is outside of the scope of this specification. management mechanisms is outside of the scope of this specification.
The only requirement for compliant implementation is that the The only requirement for compliant implementation is that the
forwarding behavior experienced by a Behavior Aggregate forwarded forwarding behavior experienced by a Behavior Aggregate forwarded
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MPLS Support of Diff-Serv August 2000 MPLS Support of Diff-Serv February 2001
over an L-LSP by the Frame Relay LSR MUST be compliant with the over an L-LSP by the Frame Relay LSR MUST be compliant with the
corresponding Diff-Serv PHB specifications. corresponding Diff-Serv PHB specifications.
Since there is only one bit (DE) for encoding the PHB drop Since there is only one bit (DE) for encoding the PHB drop
precedence value over Frame Relay links, only two different drop precedence value over Frame Relay links, only two different drop
precedence levels are supported in Frame Relay LSRs. Sections 4.2.3 precedence levels are supported in Frame Relay LSRs. Sections 4.2.3
and 4.4.3 define how the three drop precedence levels of the AFn and 4.4.3 define how the three drop precedence levels of the AFn
Ordered Aggregates are mapped to these two Frame Relay drop Ordered Aggregates are mapped to these two Frame Relay drop
precedence levels. This mapping is in accordance with the precedence levels. This mapping is in accordance with the
skipping to change at line 2410 skipping to change at line 2465
This document defines in section 6.1 a new LDP TLV, the Diffserv This document defines in section 6.1 a new LDP TLV, the Diffserv
TLV. The number for this TLV has been assigned by working group TLV. The number for this TLV has been assigned by working group
consensus according to the policies defined in [LDP]. consensus according to the policies defined in [LDP].
This document defines in section 6.2 five new LDP Status Code values This document defines in section 6.2 five new LDP Status Code values
for Diffserv-related error conditions. The values for the Status for Diffserv-related error conditions. The values for the Status
Code have been assigned by working group consensus according to the Code have been assigned by working group consensus according to the
policies defined in [LDP]. policies defined in [LDP].
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MPLS Support of Diff-Serv August 2000 MPLS Support of Diff-Serv February 2001
11. Security Considerations 11. Security Considerations
This document does not introduce any new security issues beyond This document does not introduce any new security issues beyond
those inherent in Diff-Serv, MPLS and RSVP, and may use the same those inherent in Diff-Serv, MPLS and RSVP, and may use the same
mechanisms proposed for those technologies. mechanisms proposed for those technologies.
12. Acknowledgments 12. Acknowledgments
This document has benefited from discussions with Eric Rosen, Angela This document has benefited from discussions with Eric Rosen, Angela
skipping to change at line 2463 skipping to change at line 2518
in LDP Label Request/Label Mapping messages to implicitly in LDP Label Request/Label Mapping messages to implicitly
indicate that the LSP is an E-LSP and that it uses the indicate that the LSP is an E-LSP and that it uses the
preconfigured mapping) preconfigured mapping)
A.2 Scenario 2: More than 8 BAs, no Traffic Engineering, no MPLS A.2 Scenario 2: More than 8 BAs, no Traffic Engineering, no MPLS
Protection Protection
A Service Provider running more than 8 BAs over MPLS, not performing A Service Provider running more than 8 BAs over MPLS, not performing
Traffic Engineering, not using MPLS protection and using MPLS Shim Traffic Engineering, not using MPLS protection and using MPLS Shim
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MPLS Support of Diff-Serv August 2000 MPLS Support of Diff-Serv February 2001
encapsulation in his/her network may elect to run Diff-Serv over encapsulation in his/her network may elect to run Diff-Serv over
MPLS using for each FEC: MPLS using for each FEC:
- one E-LSP established via LDP and using the preconfigured - one E-LSP established via LDP and using the preconfigured
mapping to support a set of 8 (or less) BAs, AND mapping to support a set of 8 (or less) BAs, AND
- one L-LSP per <FEC,OA> established via LDP for support of the - one L-LSP per <FEC,OA> established via LDP for support of the
other BAs. other BAs.
Operations can be summarized as follows: Operations can be summarized as follows:
- the Service Provider configures at every LSR the bi-directional - the Service Provider configures at every LSR the bi-directional
skipping to change at line 2519 skipping to change at line 2574
- the Service Provider configures at every LSR, and for every - the Service Provider configures at every LSR, and for every
interface, the scheduling behavior for each PSC (eg bandwidth interface, the scheduling behavior for each PSC (eg bandwidth
allocated to AF1) and the dropping behavior for each PHB (eg allocated to AF1) and the dropping behavior for each PHB (eg
drop profile for AF11, AF12, AF13) drop profile for AF11, AF12, AF13)
- LSRs signal establishment of a single E-LSP per FEC which will - LSRs signal establishment of a single E-LSP per FEC which will
use the preconfigured mapping: use the preconfigured mapping:
* using the RSVP protocol as specified above (i.e. no * using the RSVP protocol as specified above (i.e. no
DIFFSERV RSVP Object in the PATH message containing the DIFFSERV RSVP Object in the PATH message containing the
LABEL_REQUEST Object), OR LABEL_REQUEST Object), OR
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* using the CR-LDP protocol as specified above (i.e. no * using the CR-LDP protocol as specified above (i.e. no
Diff-Serv TLV in LDP Label Request/Label Mapping messages). Diff-Serv TLV in LDP Label Request/Label Mapping messages).
- protection is activated on all the E-LSPs in order to achieve - protection is activated on all the E-LSPs in order to achieve
MPLS protection via mechanisms outside the scope of this MPLS protection via mechanisms outside the scope of this
document. document.
A.4 Scenario 4: per-OA Traffic Engineering/MPLS Protection A.4 Scenario 4: per-OA Traffic Engineering/MPLS Protection
A Service Provider running any number of BAs over MPLS, performing A Service Provider running any number of BAs over MPLS, performing
skipping to change at line 2574 skipping to change at line 2629
established via RSVP or CR-LDP. Furthermore, the Service Provider established via RSVP or CR-LDP. Furthermore, the Service Provider
may elect to use the preconfigured mapping on all the E-LSPs. may elect to use the preconfigured mapping on all the E-LSPs.
Operations can be summarized as follows: Operations can be summarized as follows:
- the Service Provider configures at every LSR the bi-directional - the Service Provider configures at every LSR the bi-directional
mapping between each PHB and a value of the EXP field mapping between each PHB and a value of the EXP field
(e.g. 000<-->AF11, 001<-->AF12, 010<-->AF13) (e.g. 000<-->AF11, 001<-->AF12, 010<-->AF13)
- the Service Provider configures at every LSR, and for every - the Service Provider configures at every LSR, and for every
interface, the scheduling behavior for each PSC (eg bandwidth interface, the scheduling behavior for each PSC (eg bandwidth
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MPLS Support of Diff-Serv August 2000 MPLS Support of Diff-Serv February 2001
allocated to AF1) and the dropping behavior for each PHB (eg allocated to AF1) and the dropping behavior for each PHB (eg
drop profile for AF11, AF12, AF13) drop profile for AF11, AF12, AF13)
- LSRs signal establishment of one E-LSP per <FEC,OA>: - LSRs signal establishment of one E-LSP per <FEC,OA>:
* using the RSVP protocol as specified above to signal * using the RSVP protocol as specified above to signal
that the LSP is an E-LSP which uses the preconfigured mapping that the LSP is an E-LSP which uses the preconfigured mapping
(i.e. no DIFFSERV RSVP Object in the PATH message containing the (i.e. no DIFFSERV RSVP Object in the PATH message containing the
LABEL_REQUEST), OR LABEL_REQUEST), OR
* using the CR-LDP protocol as specified above to * using the CR-LDP protocol as specified above to
signal that the LSP is an E-LSP which uses the preconfigured signal that the LSP is an E-LSP which uses the preconfigured
skipping to change at line 2628 skipping to change at line 2683
- the Service Provider configures at every LSR, and for every - the Service Provider configures at every LSR, and for every
interface, the scheduling behavior for each PSC supported over interface, the scheduling behavior for each PSC supported over
the E-LSP and the dropping behavior for each corresponding PHB the E-LSP and the dropping behavior for each corresponding PHB
- the Service Provider configures at every LSR, and for every - the Service Provider configures at every LSR, and for every
interface, the scheduling behavior for each PSC supported over interface, the scheduling behavior for each PSC supported over
the L-LSPs and the dropping behavior for each corresponding PHB the L-LSPs and the dropping behavior for each corresponding PHB
- LSRs signal establishment of a single E-LSP per FEC for the non- - LSRs signal establishment of a single E-LSP per FEC for the non-
traffic engineered BAs using LDP as specified above (i.e. no traffic engineered BAs using LDP as specified above (i.e. no
Diff-Serv TLV in LDP Label Request/Label Mapping messages) Diff-Serv TLV in LDP Label Request/Label Mapping messages)
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MPLS Support of Diff-Serv August 2000 MPLS Support of Diff-Serv February 2001
- LSRs signal establishment of one L-LSP per <FEC,OA> for the - LSRs signal establishment of one L-LSP per <FEC,OA> for the
other BAs: other BAs:
* using the RSVP protocol as specified above to signal * using the RSVP protocol as specified above to signal
the L-LSP PSC (i.e. DIFFSERV RSVP Object in the PATH message the L-LSP PSC (i.e. DIFFSERV RSVP Object in the PATH message
containing the LABEL_REQUEST Object), OR containing the LABEL_REQUEST Object), OR
* using the CR-LDP protocol as specified above to * using the CR-LDP protocol as specified above to
signal the L-LSP PSC (i.e. Diff-Serv TLV in LDP Label signal the L-LSP PSC (i.e. Diff-Serv TLV in LDP Label
Request/Label Mapping messages). Request/Label Mapping messages).
- protection is not activated on the E-LSPs. - protection is not activated on the E-LSPs.
skipping to change at line 2683 skipping to change at line 2738
- have Shortest Path Routing used for all the Diff-Serv traffic. - have Shortest Path Routing used for all the Diff-Serv traffic.
This is the closest model to provisioned Diff-Serv over non-MPLS IP. This is the closest model to provisioned Diff-Serv over non-MPLS IP.
In that case, E-LSPs and/or L-LSPs would be established without In that case, E-LSPs and/or L-LSPs would be established without
signaled bandwidth. signaled bandwidth.
B.2 Scenario 2: Bandwidth Reservation for per-PSC Admission Control B.2 Scenario 2: Bandwidth Reservation for per-PSC Admission Control
Consider the case where a network administrator elects to: Consider the case where a network administrator elects to:
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MPLS Support of Diff-Serv August 2000 MPLS Support of Diff-Serv February 2001
- have Diff-Serv resources entirely provisioned off-line (e.g. via - have Diff-Serv resources entirely provisioned off-line (e.g. via
Command Line Interface, via SNMP, via COPS,...) Command Line Interface, via SNMP, via COPS,...)
- use L-LSPs - use L-LSPs
- have Constraint Based Routing performed separately for each PSC, - have Constraint Based Routing performed separately for each PSC,
where one of the constraints is availability of bandwidth from where one of the constraints is availability of bandwidth from
the bandwidth allocated to the relevant PSC. the bandwidth allocated to the relevant PSC.
In that case, L-LSPs would be established with signaled bandwidth. In that case, L-LSPs would be established with signaled bandwidth.
The bandwidth signaled at L-LSP establishment would be used by LSRs The bandwidth signaled at L-LSP establishment would be used by LSRs
skipping to change at line 2718 skipping to change at line 2773
In that case, L-LSPs would be established with signaled bandwidth. In that case, L-LSPs would be established with signaled bandwidth.
The bandwidth signaled at L-LSP establishment would be used by LSRs The bandwidth signaled at L-LSP establishment would be used by LSRs
to attempt to adjust the resources allocated to the relevant PSC to attempt to adjust the resources allocated to the relevant PSC
(e.g. scheduling weight) and then perform admission control to (e.g. scheduling weight) and then perform admission control to
ensure that the constraint on availability of bandwidth for the ensure that the constraint on availability of bandwidth for the
relevant PSC is met after the adjustment. relevant PSC is met after the adjustment.
References References
[MPLS_ARCH] Rosen et al., "Multiprotocol label switching [MPLS_ARCH] Rosen et al., "Multiprotocol label switching
Architecture", work in progress, draft-ietf-mpls-arch-06.txt, August Architecture", RFC-3031, January 2001.
1999.
[MPLS_ENCAPS] Rosen et al., "MPLS Label Stack Encoding, work in [MPLS_ENCAPS] Rosen et al., "MPLS Label Stack Encoding", RFC-3032,
progress, draft-ietf-mpls-label-encaps-07.txt, September 1999. January 2001.
[MPLS_ATM] Davie et al., "MPLS using LDP and ATM VC Switching", work [MPLS_ATM] Davie et al., "MPLS using LDP and ATM VC Switching", RFC-
in progress, draft-ietf-mpls-atm-04.txt, June 2000. 3035, January 2001.
[MPLS_FR] Conta et al., "Use of Label Switching on Frame Relay [MPLS_FR] Conta et al., "Use of Label Switching on Frame Relay
Networks Specification", work in progress, draft-ietf-mpls-fr- Networks Specification", RFC-3034, January 2001.
06.txt, June 2000.
[DIFF_ARCH] Blake et al., "An architecture for Differentiated [DIFF_ARCH] Blake et al., "An architecture for Differentiated
Services", RFC-2475, December 1998. Services", RFC-2475, December 1998.
[DIFF_AF] Heinanen et al., "Assured Forwarding PHB Group", RFC-2597, [DIFF_AF] Heinanen et al., "Assured Forwarding PHB Group", RFC-2597,
June 1999. June 1999.
Le Faucheur et. al 50
MPLS Support of Diff-Serv August 2000
[DIFF_EF] Jacobson et al., "An Expedited Forwarding PHB", RFC-2598, [DIFF_EF] Jacobson et al., "An Expedited Forwarding PHB", RFC-2598,
June 1999. June 1999.
Le Faucheur et. al 51
MPLS Support of Diff-Serv February 2001
[DIFF_HEADER] Nichols et al., "Definition of the Differentiated [DIFF_HEADER] Nichols et al., "Definition of the Differentiated
Services Field (DS Field) in the IPv4 and IPv6 Headers", RFC-2474, Services Field (DS Field) in the IPv4 and IPv6 Headers", RFC-2474,
December 1998. December 1998.
[ECN] Ramakrishnan et al., "A Proposal to add Explicit Congestion [ECN] Ramakrishnan et al., "A Proposal to add Explicit Congestion
Notification (ECN) to IP", RFC-2481, January 1999. Notification (ECN) to IP", RFC-2481, January 1999.
[LDP] Andersson et al., "LDP Specification", work in progress, [LDP] Andersson et al., "LDP Specification", RFC-3036, January 2001
draft-ietf-mpls-ldp-08.txt, June 2000
[RSVP_MPLS_TE] Awduche et al, "Extensions to RSVP for LSP Tunnels", [RSVP_MPLS_TE] Awduche et al, "Extensions to RSVP for LSP Tunnels",
work in progress, draft-ietf-mpls-rsvp-lsp-tunnel-05.txt, February work in progress, draft-ietf-mpls-rsvp-lsp-tunnel-07.txt, August
2000 2000
[CR-LDP_MPLS_TE] Jamoussi et al., "Constraint-Based LSP Setup using [CR-LDP_MPLS_TE] Jamoussi et al., "Constraint-Based LSP Setup using
LDP", work in progress, draft-ietf-mpls-cr-ldp-03.txt, October 1999 LDP", work in progress, draft-ietf-mpls-cr-ldp-04.txt, July 2000
[PHBID] Brim et al., "Per Hop Behavior Identification Codes" [PHBID] Brim et al., "Per Hop Behavior Identification Codes"
RFC 2836, May 2000 RFC-2836, May 2000
[DIFF_NEW] Grossman, "New Terminology for Diffserv", work in [DIFF_NEW] Grossman, "New Terminology for Diffserv", work in
progress, draft-ietf-diffserv-new-terms-02.txt, November 1999 progress, draft-ietf-diffserv-new-terms-03.txt, August 2000
[IEEE_802.1] ISO/IEC 15802-3: 1998 ANSI/IEEE Std 802.1D, 1998 [IEEE_802.1] ISO/IEC 15802-3: 1998 ANSI/IEEE Std 802.1D, 1998
Edition (Revision and redesignation of ISO/IEC 10038:98 Edition (Revision and redesignation of ISO/IEC 10038:98
[ANSI/IEEE Std 802.1D, 1993 Edition], incorporating IEEE [ANSI/IEEE Std 802.1D, 1993 Edition], incorporating IEEE
supplements P802.1p, 802.1j-1996, 802.6k-1992, 802.11c-1998, and supplements P802.1p, 802.1j-1996, 802.6k-1992, 802.11c-1998, and
P802.12e) P802.12e)
[DIFF_TUNNEL] Black, "Differentiated Services and Tunnels", work in [DIFF_TUNNEL] Black, "Differentiated Services and Tunnels",
progress, draft-ietf-diffserv-tunnels-02-txt, July 2000. RFC-2983, October 2000.
[MPLS_VPN] Rosen et al., "BGP/MPLS VPNs", work in progress, draft- [MPLS_VPN] Rosen et al., "BGP/MPLS VPNs", work in progress, draft-
rosen-rfc2547bis-01.txt, May 2000. rosen-rfc2547bis-02.txt, July 2000.
[RSVP] Braden et al., "Resource ReSerVation Protocol (RSVP) - [RSVP] Braden et al., "Resource ReSerVation Protocol (RSVP) -
Version 1 Functional Specification", RFC-2205, September 1997. Version 1 Functional Specification", RFC-2205, September 1997.
[IANA] T. Narten, H. Alvestrand, "Guidelines for Writing an IANA [IANA] T. Narten, H. Alvestrand, "Guidelines for Writing an IANA
Considerations Section in RFCs", RFC 2434, October 1998. Considerations Section in RFCs", RFC 2434, October 1998.
Authors' Address: Authors' Address:
Francois Le Faucheur Francois Le Faucheur
Cisco Systems Cisco Systems
Petra B - Les Lucioles - 291, rue Albert Caquot - 06560 Valbonne - Village d'Entreprise Green Side - Batiment T3
400, Avenue de Roumanille
06410 Biot-Sophia Antipolis
France France
Phone: +33 4 97 23 26 19
Le Faucheur et. al 51 Le Faucheur et. al 52
MPLS Support of Diff-Serv August 2000 MPLS Support of Diff-Serv February 2001
Phone: +33 4 92 96 75 64
Email: flefauch@cisco.com Email: flefauch@cisco.com
Liwen Wu Liwen Wu
Cisco Systems Cisco Systems
250 Apollo Drive, Chelmsford, MA 01824, 250 Apollo Drive, Chelmsford, MA 01824,
USA USA
Phone: +1 (978) 244-3087 Phone: +1 (978) 244-3087
Email: liwwu@cisco.com Email: liwwu@cisco.com
Bruce Davie Bruce Davie
skipping to change at line 2847 skipping to change at line 2901
Alcatel Alcatel
5 rue Noel-Pons 5 rue Noel-Pons
92734 Nanterre Cedex 92734 Nanterre Cedex
France France
E-mail:pierrick.cheval@alcatel.fr E-mail:pierrick.cheval@alcatel.fr
Juha Heinanen Juha Heinanen
Telia Finland Telia Finland
E-mail: jh@lohi.eng.telia.fi E-mail: jh@lohi.eng.telia.fi
Le Faucheur et. al 52 Le Faucheur et. al 53
MPLS Support of Diff-Serv August 2000 MPLS Support of Diff-Serv February 2001
Full Copyright Statement Full Copyright Statement
Copyright (C) The Internet Society (2000). All Rights Reserved. Copyright (C) The Internet Society (2000). All Rights Reserved.
This document and translations of it may be copied and furnished to This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph kind, provided that the above copyright notice and this paragraph
skipping to change at line 2878 skipping to change at line 2932
The limited permissions granted above are perpetual and will not be The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns. revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE." MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE."
Le Faucheur et. al 53 Le Faucheur et. al 54
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