draft-ietf-mpls-rsvpte-attributes-05.txt   rfc4420.txt 
Network Working Group Adrian Farrel (Editor)
Updates: RFC3209 and RFC3473 Old Dog Consulting Network Working Group A. Farrel, Ed.
Category: Standards Track Dimitri Papadimitriou Request for Comments: 4420 Old Dog Consulting
Expires: November 2005 Alcatel Updates: 3209, 3473 D. Papadimitriou
Jean-Philippe Vasseur Category: Standards Track Alcatel
J.-P. Vasseur
Cisco Systems, Inc. Cisco Systems, Inc.
Arthi Ayyangar A. Ayyangar
Juniper Networks Juniper Networks
February 2006
May 2005
Encoding of Attributes for Multiprotocol Label Switching (MPLS) Encoding of Attributes for Multiprotocol Label Switching (MPLS)
Label Switched Path (LSP) Establishment Using RSVP-TE Label Switched Path (LSP) Establishment Using
Resource ReserVation Protocol-Traffic Engineering (RSVP-TE)
draft-ietf-mpls-rsvpte-attributes-05.txt
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Abstract Abstract
Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) may Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) may
be established using the Resource Reservation Protocol Traffic be established using the Resource Reservation Protocol Traffic
Engineering extensions (RSVP-TE). This protocol includes an object Engineering (RSVP-TE) extensions. This protocol includes an object
(the SESSION_ATTRIBUTE object) which carries a flags field used to (the SESSION_ATTRIBUTE object) that carries a Flags field used to
indicate options and attributes of the LSP. That flags field has indicate options and attributes of the LSP. That Flags field has
eight bits allowing for eight options to be set. Recent proposals in eight bits allowing for eight options to be set. Recent proposals in
many documents that extend RSVP-TE have suggested uses for each of many documents that extend RSVP-TE have suggested uses for each of
the previously unused bits. the previously unused bits.
This document defines a new object for RSVP-TE messages that allows This document defines a new object for RSVP-TE messages that allows
the signaling of further attribute bits and also the carriage of the signaling of further attribute bits and also the carriage of
arbitrary attribute parameters to make RSVP-TE easily extensible to arbitrary attribute parameters to make RSVP-TE easily extensible to
support new requirements. Additionally, this document defines a way support new requirements. Additionally, this document defines a way
to record the attributes applied to the LSP on a hop-by-hop basis. to record the attributes applied to the LSP on a hop-by-hop basis.
The object mechanisms defined in this document are equally applicable The object mechanisms defined in this document are equally applicable
to Generalized MPLS (GMPLS) Packet Switch Capable (PSC) LSPs and to to Generalized MPLS (GMPLS) Packet Switch Capable (PSC) LSPs and to
GMPLS non-PSC LSPs. GMPLS non-PSC LSPs.
Contents Table of Contents
1. Introduction and Problem Statement 3 1. Introduction and Problem Statement ..............................3
1.1 Applicability to Generalized MPLS 4 1.1. Applicability to Generalized MPLS ..........................4
1.2 A Rejected Alternate Solution 4 1.2. A Rejected Alternate Solution ..............................4
2. Terminology 5 2. Terminology .....................................................5
3. Attributes TLVs 5 3. Attributes TLVs .................................................5
3.1 Attributes Flags TLV 6 3.1. Attributes Flags TLV .......................................6
4. LSP_ATTRIBUTES Object 6 4. LSP_ATTRIBUTES Object ...........................................6
4.1 Format 7 4.1. Format .....................................................7
4.2 Generic Processing Rules for Path Messages 7 4.2. Generic Processing Rules for Path Messages .................7
4.3 Generic Processing Rules for Resv Messages 8 4.3. Generic Processing Rules for Resv Messages .................8
5. LSP_REQUIRED_ATTRIBUTES Object 8 5. LSP_REQUIRED_ATTRIBUTES Object ..................................9
5.1 Format 9 5.1. Format .....................................................9
5.2 Generic Processing Rules 9 5.2. Generic Processing Rules ...................................9
6. Inheritance Rules 10 6. Inheritance Rules ..............................................10
7. Recording Attributes Per-LSP 10 7. Recording Attributes Per LSP ...................................11
7.1 Requirements 10 7.1. Requirements ..............................................11
7.2 RRO Attributes Subobject 10 7.2. RRO Attributes Subobject ..................................11
7.3 Procedures 11 7.3. Procedures ................................................12
7.3.1 Subobject Presence Rules 11 7.3.1. Subobject Presence Rules ...........................12
7.3.2 Reporting Compliance with LSP Attributes 12 7.3.2. Reporting Compliance with LSP Attributes ...........12
7.3.3 Reporting Per-Hop Attributes 12 7.3.3. Reporting Per-Hop Attributes .......................13
7.3.4 Default Behavior 12 7.3.4. Default Behavior ...................................13
8. Summary of Attribute Bit Allocation 12 8. Summary of Attribute Bit Allocation ............................13
9. Message Formats 13 9. Message Formats ................................................14
10. Guidance for Key Application Scenarios 14 10. Guidance for Key Application Scenarios ........................14
10.1 Communicating to Egress LSRs 14 10.1. Communicating to Egress LSRs .............................15
10.2 Communicating to Key Transit LSRs 15 10.2. Communicating to Key Transit LSRs ........................15
10.3 Communicating to All LSRs 15 10.3. Communicating to All LSRs ................................16
11. IANA Considerations 15 11. IANA Considerations ...........................................16
11.1 New RSVP C-Nums and C-Types 15 11.1. New RSVP C-Nums and C-Types ..............................16
11.2 New TLV Space 16 11.2. New TLV Space ............................................17
11.3 Attributes Flags 16 11.3. Attributes Flags .........................................17
11.4 SESSION_ATTRIBUTE Flags Field 17 11.4. New Error Codes ..........................................18
11.5 New Error Codes 17 11.5. New Record Route Subobject Identifier ....................18
11.6 New Record Route Subobject Identifier 17 12. Security Considerations .......................................18
12. Security Considerations 17 13. Acknowledgements ..............................................19
13. Acknowledgements 18 14. Normative References ..........................................19
14. Intellectual Property Consideration 18 15. Informative References ........................................19
15. Normative References 18
16. Informative References 19
17. Authors' Addresses 19
18. Disclaimer of Validity 20
19. Full Copyright Statement 20
1. Introduction and Problem Statement 1. Introduction and Problem Statement
Traffic Engineered Multiprotocol Label Switching (MPLS) Label Traffic-Engineered Multiprotocol Label Switching (MPLS) Label
Switched Paths (LSPs) [RFC3031] may be set up using the Path message Switched Paths (LSPs) [RFC3031] may be set up using the Path message
of the RSVP-TE signaling protocol [RFC3209]. The Path message of the RSVP-TE signaling protocol [RFC3209]. The Path message
includes the SESSION_ATTRIBUTE object which carries a flags field includes the SESSION_ATTRIBUTE object, which carries a Flags field
used to indicate desired options and attributes of the LSP. used to indicate desired options and attributes of the LSP.
The flags field in the SESSION_ATTRIBUTE object has eight bits. Just The Flags field in the SESSION_ATTRIBUTE object has eight bits. Just
three of those bits are assigned in [RFC3209]. A further two bits are three of those bits are assigned in [RFC3209]. A further two bits
assigned in [FRR] for fast re-reroute functionality leaving only are assigned in [RFC4090] for fast re-reroute functionality leaving
three bits available. Several recent proposals and Internet Drafts only three bits available. Several recent proposals and Internet
have demonstrated that there is a high demand for the use of the Drafts have demonstrated that there is a high demand for the use of
other three bits. Some, if not all, of those proposals are likely to the other three bits. Some, if not all, of those proposals are
go forward as RFCs resulting in depletion or near depletion of the likely to go forward as RFCs resulting in depletion or near depletion
flags field and a consequent difficulty in signaling new options and of the Flags field and a consequent difficulty in signaling new
attributes that may be developed in the future. options and attributes that may be developed in the future.
This document defines a new object for RSVP-TE messages that allows This document defines a new object for RSVP-TE messages that allows
the signaling of further attributes bits. The new object is the signaling of further attributes bits. The new object is
constructed from TLVs, and a new TLV is defined to carry a variable constructed from TLVs, and a new TLV is defined to carry a variable
number of attributes bits. number of attributes bits.
The new RSVP-TE message object is quite flexible, due to the use of The new RSVP-TE message object is quite flexible, due to the use of
the TLV format and allows: the TLV format and allows:
- future specification of bit flags - future specification of bit flags
- additional options and atttribute paramerters carried in TLV - additional options and attribute parameters carried in TLV
format. format.
Note that the LSP Attributes defined in this document are Note that the LSP Attributes defined in this document are
specifically scoped to an LSP. They may be set differently on specifically scoped to an LSP. They may be set differently on
separate LSPs with the same Tunnel ID between the same source and separate LSPs with the same Tunnel ID between the same source and
destination (that is, within the same Session). destination (that is, within the same session).
It is noted that some options and attributes do not need to be It is noted that some options and attributes do not need to be acted
acted on by all Label Switched Routers (LSRs) along the path of the on by all Label Switched Routers (LSRs) along the path of the LSP.
LSP. In particular, these options and attributes may apply only to In particular, these options and attributes may apply only to key
key LSRs on the path such as the ingress LSR and egress LSR. Special LSRs on the path such as the ingress LSR and egress LSR. Special
transit LSRs, such as Area or AS Border Routers (ABRs/ASBRs) may also transit LSRs, such as Area or Autonomous System Border Routers (ABRs
fall into this category. This means that the new options and or ASBRs), may also fall into this category. This means that the new
attributes should be signaled transparently, and only examined at options and attributes should be signaled transparently, and only
those points that need to act on them. examined at those points that need to act on them.
On the other hand, other options and attributes may require action On the other hand, other options and attributes may require action at
at all transit LSRs along the path of the LSP. Inability to support all transit LSRs along the path of the LSP. Inability to support the
the required attributes by one of those transit LSRs may require the required attributes by one of those transit LSRs may require the LSR
LSR to refuse the establishment of the LSP. to refuse the establishment of the LSP.
These considerations are particularly important in the context of These considerations are particularly important in the context of
backwards compatibility. In general, it should be possible to provide backward compatibility. In general, it should be possible to provide
new MPLS services across a legacy network without upgrading those new MPLS services across a legacy network without upgrading those
LSRs that do not need to participate actively in the new services. LSRs that do not need to participate actively in the new services.
Moreover, some features just require action on specific intermediate Moreover, some features just require action on specific intermediate
hops, and not on every visited LSR. hops, and not on every visited LSR.
Note that options already specified for the SESSION_ATTRIBUTE object Note that options already specified for the SESSION_ATTRIBUTE object
in pre-existing RFCs are not migrated to the new mechanisms described in preexisting RFCs are not migrated to the new mechanisms described
in this document. in this document.
RSVP includes a way for unrecognized objects to be transparently RSVP includes a way for unrecognized objects to be transparently
forwarded by transit nodes without them refusing the incoming forwarded by transit nodes without them refusing the incoming
protocol messages and without the objects being stripped from the protocol messages and without the objects being stripped from the
outgoing protocol message (see [RFC2205] Section 3.10). This outgoing protocol message (see [RFC2205], Section 3.10). This
capability extends to RSVP-TE and provides a good way to ensure that capability extends to RSVP-TE and provides a good way to ensure that
only those LSRs that understand a particular object examine it. only those LSRs that understand a particular object examine it.
This document distinguishes between options and attributes that are This document distinguishes between options and attributes that are
only required at key LSRs along the path of the LSP, and those that only required at key LSRs along the path of the LSP, and those that
must be acted on by every LSR along the LSP. Two LSP Attributes must be acted on by every LSR along the LSP. Two LSP Attributes
objects are defined in this document: using the C-Num definition objects are defined in this document: using the C-Num definition
rules inherrited from [RFC2205], the first is passed transparently rules inherited from [RFC2205], the first is passed transparently by
by LSRs that do not recognize it, and the second causes LSP setup LSRs that do not recognize it, and the second causes LSP setup
failure with the generation of a PathErr message with an failure with the generation of a PathErr message with an appropriate
appropriate Error Code if an LSR does not recognize it. Error Code if an LSR does not recognize it.
1.1 Applicability to Generalized MPLS 1.1. Applicability to Generalized MPLS
The RSVP-TE signaling protocol also forms the basis of a signaling The RSVP-TE signaling protocol also forms the basis of a signaling
protocol for Generalized MPLS (GMPLS) as described in [RFC3471] and protocol for Generalized MPLS (GMPLS) as described in [RFC3471] and
[RFC3473]. The extensions described in this document are equally [RFC3473]. The extensions described in this document are equally
applicable to MPLS and GMPLS. applicable to MPLS and GMPLS.
1.2 A Rejected Alternate Solution 1.2. A Rejected Alternate Solution
A rejected alternate solution was to define a new C-Type for the A rejected alternate solution was to define a new C-Type for the
existing SESSION_ATTRIBUTE object. This new C-Type could allow a existing SESSION_ATTRIBUTE object. This new C-Type could allow a
larger Flags field and address the immediate problem. larger Flags field and address the immediate problem.
This solution was rejected because: This solution was rejected because:
- A new C-Type is not backward compatible with deployed - A new C-Type is not backward compatible with deployed
implementations that expect to see a C-Type of 1 or 7. It is implementations that expect to see a C-Type of 1 or 7. It is
important that any solution be capable of carrying new attributes important that any solution be capable of carrying new attributes
transparently across legacy LSRs if those LSRs are not required to transparently across legacy LSRs if those LSRs are not required to
act on the attributes. act on the attributes.
- Support for arbitrary attributes parameters through TLVs would
have meant a significant change of substance to the existing - Support for arbitrary attributes parameters through TLVs would have
object. meant a significant change of substance to the existing object.
2. Terminology 2. Terminology
This document uses terminology from the MPLS architecture document This document uses terminology from the MPLS architecture document
[RFC3031] and from the RSVP-TE protocol specification [RFC3209] which [RFC3031] and from the RSVP-TE protocol specification [RFC3209],
inherits from the RSVP specification [RFC2205]. It also makes uses of which inherits from the RSVP specification [RFC2205]. It also makes
the Generalized MPLS RSVP-TE terminology introduced in [RFC3471] and use of the Generalized MPLS RSVP-TE terminology introduced in
[RFC3473]. [RFC3471] and [RFC3473].
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2219]. document are to be interpreted as described in [RFC2119].
3. Attributes TLVs 3. Attributes TLVs
Attributes carried by the new objects defined in this document are Attributes carried by the new objects defined in this document are
encoded within TLVs. One or more TLVs may be present in each object. encoded within TLVs. One or more TLVs may be present in each object.
There are no ordering rules for TLVs and no interpretation should be There are no ordering rules for TLVs, and no interpretation should be
placed on the order in which TLVs are received. placed on the order in which TLVs are received.
Each TLV is encoded as follows. Each TLV is encoded as follows.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
// Value // // Value //
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
The identifier of the TLV. The identifier of the TLV.
Length Length
The length of the value field in bytes. Thus if no value The length of the Value field in bytes. Thus, if no Value
field is present the length field contains the value zero. field is present the Length field contains the value zero.
Each value field must be zero padded at the end to take it Each Value field must be zero padded at the end to take it up
up to a four byte boundary - the padding is not included in to a four byte boundary -- the padding is not included in the
the length so that a one byte value would be encoded in an length so that a one byte value would be encoded in an eight
eight byte TLV with length field set to one. byte TLV with Length field set to one.
Value Value
The data for the TLV padded as described above. The data for the TLV padded as described above.
3.1 Attributes Flags TLV 3.1. Attributes Flags TLV
This document defines only one TLV type value. Type 1 indicates the This document defines only one TLV type value. Type 1 indicates the
Attributes Flags TLV. Other TLV types may be defined in future with Attributes Flags TLV. Other TLV types may be defined in the future
type values assigned by IANA (see section 11.2). with type values assigned by IANA (see Section 11.2).
The Attributes Flags TLV may be present in an LSP_ATTRIBUTES object The Attributes Flags TLV may be present in an LSP_ATTRIBUTES object
and/or an LSP_REQUIRED_ATTRIBUTES object defined in Sections 4 and 5. and/or an LSP_REQUIRED_ATTRIBUTES object defined in Sections 4 and 5.
The bits in the TLV represent the same attributes regardless of which The bits in the TLV represent the same attributes regardless of which
object carries the TLV. Documents that define individual bits MUST object carries the TLV. Documents that define individual bits MUST
specify whether the bit may be set in one object or the other, or specify whether the bit may be set in one object or the other, or
both. It is not expected that a bit will be set in both objects on a both. It is not expected that a bit will be set in both objects on a
single Path message at the same time, but this is not ruled out by single Path message at the same time, but this is not ruled out by
this document. this document.
The Attribute Flags TLV value field is an array of units of 32 flags The Attribute Flags TLV Value field is an array of units of 32 flags
numbered from the MSB as bit zero. The length field for this TLV is numbered from the most significant bit as bit zero. The Length field
therefore always a multiple of 4 bytes, regardless of the number of for this TLV is therefore always a multiple of 4 bytes, regardless of
bits carried and no padding is required. the number of bits carried and no padding is required.
Unassigned bits are considered as reserved and MUST be set to zero Unassigned bits are considered as reserved and MUST be set to zero on
on transmission by the originator of the object. Bits not contained transmission by the originator of the object. Bits not contained in
in the TLV MUST be assumed to be set to zero. If the TLV is absent the TLV MUST be assumed to be set to zero. If the TLV is absent
either because it is not contained in the LSP_ATTRIBUTES or either because it is not contained in the LSP_ATTRIBUTES or
LSP_REQUIRED_ATTRIBUTES object, or because those objects are LSP_REQUIRED_ATTRIBUTES object, or because those objects are
themselves absent, all processing MUST be performed as though the themselves absent, all processing MUST be performed as though the
bits were present and set to zero. That is to say, assigned bits that bits were present and set to zero. That is to say, assigned bits
are not present either because the TLV is deliberatley forshortened, that are not present either because the TLV is deliberately
or because the TLV is not included MUST be treated as though they are foreshortened or because the TLV is not included MUST be treated as
present and are set to zero. though they are present and are set to zero.
No bits are defined in this document. The assignment of bits is No bits are defined in this document. The assignment of bits is
managed by IANA (see section 11.3). managed by IANA (see Section 11.3).
4. LSP_ATTRIBUTES Object 4. LSP_ATTRIBUTES Object
The LSP_ATTRIBUTES object is used to signal attributes required in The LSP_ATTRIBUTES object is used to signal attributes required in
support of an LSP, or to indicate the nature or use of an LSP where support of an LSP, or to indicate the nature or use of an LSP where
that information is not required to be acted on by all transit LSRs. that information is not required to be acted on by all transit LSRs.
Specifically, if an LSR does not support the object, it forwards it Specifically, if an LSR does not support the object, it forwards it
unexamined and unchanged. This facilitates the exchange of attributes unexamined and unchanged. This facilitates the exchange of
across legacy networks that do not support this new object. attributes across legacy networks that do not support this new
object.
This object effectively extends the flags field in the SESSION_ This object effectively extends the Flags field in the
ATTRIBUTE object and allows for the future inclusion of more complex SESSION_ATTRIBUTE object and allows for the future inclusion of more
objects through TLVs. complex objects through TLVs.
Note that some function may require an LSR to inspect both the Note that some function may require an LSR to inspect both the
SESSION_ATTRIBUTE object, and the LSP_ATTRIBUTES or SESSION_ATTRIBUTE object and the LSP_ATTRIBUTES or
LSP_REQUIRED_ATTRIBUTES object. LSP_REQUIRED_ATTRIBUTES object.
The LSP_ATTRIBUTES object may also be used to report LSP operational The LSP_ATTRIBUTES object may also be used to report LSP operational
state on a Resv even when no LSP_ATTRIBUTES or LSP_REQUIRED_ state on a Resv even when no LSP_ATTRIBUTES or
ATTRIBUTES object was carried on the corresponding Path message. The LSP_REQUIRED_ATTRIBUTES object was carried on the corresponding Path
object is added or updated by LSRs that support the object. LSRs that message. The object is added or updated by LSRs that support the
do not understand the object or have nothing to report, do not add object. LSRs that do not understand the object or have nothing to
the object and forward it unchanged on Resv messages that they report do not add the object and forward it unchanged on Resv
generate. messages that they generate.
The LSP_ATTRIBUTES object class is TBD of the form 11bbbbbb. This The LSP_ATTRIBUTES object class is 197 of the form 11bbbbbb. This
C-Num value (see Section 8) ensures that LSRs that do not recognize C-Num value (see [RFC2205], Section 3.10) ensures that LSRs that do
the object pass it on transparently. not recognize the object pass it on transparently.
One C-Type is defined, C-Type = 1 for LSP Attributes. One C-Type is defined, C-Type = 1 for LSP Attributes.
This object is optional and may be placed on Path messages to convey This object is optional and may be placed on Path messages to convey
additional information about the desired attributes of the LSP, and. additional information about the desired attributes of the LSP, and
on Resv messages to report operational state. on Resv messages to report operational state.
4.1 Format 4.1. Format
LSP_ATTRIBUTES class = TBD, C-Type = 1 LSP_ATTRIBUTES class = 197, C-Type = 1
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
// Attributes TLVs // // Attributes TLVs //
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Attributes TLVs are encoded as described in Section 3. The Attributes TLVs are encoded as described in Section 3.
4.2 Generic Processing Rules for Path Messages 4.2. Generic Processing Rules for Path Messages
An LSR that does not support this object is required to pass it on An LSR that does not support this object is required to pass it on
unaltered as indicated by the C-Num and the rules defined in unaltered as indicated by the C-Num and the rules defined in
[RFC2205]. [RFC2205].
An LSR that does support this object, but does not recognize a TLV An LSR that does support this object, but does not recognize a TLV
type code carried in this object MUST pass the TLV on unaltered type code carried in this object, MUST pass the TLV on unaltered in
in the LSP_ATTRIBUTES object that it places in the Path message the LSP_ATTRIBUTES object that it places in the Path message that it
that it sends downstream. sends downstream.
An LSR that does support this object and recognizes a TLV but does An LSR that does support this object and recognizes a TLV, but does
not support the attribute defined by the TLV MUST act as specified in not support the attribute defined by the TLV, MUST act as specified
the document that defines the TLV. in the document that defines the TLV.
An LSR that supports the Attributes Flags TLV, but does not An LSR that supports the Attributes Flags TLV, but does not recognize
recognize a bit set in the Attributes Flags TLV MUST forward the a bit set in the Attributes Flags TLV, MUST forward the TLV
TLV unchanged. unchanged.
An LSR that supports the Attributes Flags TLV and recognizes a bit An LSR that supports the Attributes Flags TLV and recognizes a bit
that is set but does not support the indicated attribute MUST act as that is set, but does not support the indicated attribute, MUST act
specified in the document that defines the bit. as specified in the document that defines the bit.
4.3 Generic Processing Rules for Resv Messages 4.3. Generic Processing Rules for Resv Messages
An LSR that wishes to report operational status of an LSP may include An LSR that wishes to report operational status of an LSP may include
this object in a Resv message, or update the object that is already this object in a Resv message, or update the object that is already
carried in a Resv message. carried in a Resv message.
Note that this usage reports the state of the entire LSP and not the Note that this usage reports the state of the entire LSP and not the
state of the LSP at an individual LSR. This latter function is state of the LSP at an individual LSR. This latter function is
achieved using the LSP Attributes subobject of the Record Route achieved using the LSP Attributes subobject of the Record Route
object as described in Section 7. object (RRO) as described in Section 7.
The bits in the Attributes TLV may be used to report operational The bits in the Attributes TLV may be used to report operational
status for the whole LSP. For example, an egress LSR may report a status for the whole LSP. For example, an egress LSR may report a
particular status by setting a bit. LSRs within the network that particular status by setting a bit. LSRs within the network that
determine that this status has not been achieved may clear the bit determine that this status has not been achieved may clear the bit as
as they forward the Resv message. they forward the Resv message.
Observe that LSRs that do not support the object or do not support Observe that LSRs that do not support the object or do not support
the function characterized by a particular bit in the Attributes TLV the function characterized by a particular bit in the Attributes TLV
will not clear the bit when forwarding the Resv. Thus, care must be will not clear the bit when forwarding the Resv. Thus, care must be
taken in defining the usage of this object on a Resv. The usage of taken in defining the usage of this object on a Resv. The usage of
an individual bit in the Attributes TLV of the LSP_ATTRIBUTES object an individual bit in the Attributes TLV of the LSP_ATTRIBUTES object
on a Resv must be fully defined in the document that defines the bit. on a Resv must be fully defined in the document that defines the bit.
Additional TLVs may also be defined to be carried in this object on Additional TLVs may also be defined to be carried in this object on a
a Resv. Resv.
An LSR that does not support this object will pass it on unaltered An LSR that does not support this object will pass it on unaltered
because of the C-Num. because of the C-Num.
5. LSP_REQUIRED_ATTRIBUTES Object 5. LSP_REQUIRED_ATTRIBUTES Object
The LSP_REQUIRED_ATTRIBUTES object is used to signal attributes The LSP_REQUIRED_ATTRIBUTES object is used to signal attributes
required in support of an LSP, or to indicate the nature or use of required in support of an LSP, or to indicate the nature or use of an
an LSP where that information MUST be inspected at each transit LSR. LSP where that information MUST be inspected at each transit LSR.
Specifically, each transit LSR MUST examine the attributes in the Specifically, each transit LSR MUST examine the attributes in the
LSP_REQUIRED_ATTRIBUTES object and MUST NOT forward the object LSP_REQUIRED_ATTRIBUTES object and MUST NOT forward the object
without acting on its contents. without acting on its contents.
This object effectively extends the flags field in the SESSION_ This object effectively extends the Flags field in the
ATTRIBUTE object and allows for the future inclusion of more complex SESSION_ATTRIBUTE object and allows for the future inclusion of more
objects through TLVs. It complements the LSP_ATTRIBUTES object. complex objects through TLVs. It complements the LSP_ATTRIBUTES
object.
The LSP_REQUIRED_ATTRIBUTES object class is TBD of the form 0bbbbbbb. The LSP_REQUIRED_ATTRIBUTES object class is 67 of the form 0bbbbbbb.
This C-Num value ensures that LSRs that do not recognize the object This C-Num value ensures that LSRs that do not recognize the object
reject the LSP setup effectively saying that they do not support the reject the LSP setup effectively saying that they do not support the
attributes requested. This means that this object SHOULD only be used attributes requested. This means that this object SHOULD only be
for attributes that require support at some transit LSRs and so used for attributes that require support at some transit LSRs and so
require examination at all transit LSRs. See Section 4 for how end- require examination at all transit LSRs. See Section 4 for how end-
to-end and selective attributes are signaled. to-end and selective attributes are signaled.
One C-Type is defined, C-Type = 1 for LSP Required Attributes. One C-Type is defined, C-Type = 1 for LSP Required Attributes.
This object is optional and may be placed on Path messages to convey This object is optional and may be placed on Path messages to convey
additional information about the desired attributes of the LSP. additional information about the desired attributes of the LSP.
5.1 Format 5.1. Format
LSP_REQUIRED_ATTRIBUTES class = TBD, C-Type = 1 LSP_REQUIRED_ATTRIBUTES class = 67, C-Type = 1
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
// Attributes TLVs // // Attributes TLVs //
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Attributes TLVs are encoded as described in Section 3. The Attributes TLVs are encoded as described in Section 3.
5.2 Generic Processing Rules 5.2. Generic Processing Rules
An LSR that does not support this object will use a PathErr to reject An LSR that does not support this object will use a PathErr to reject
the Path message based on the C-Num using the error code "Unknown the Path message based on the C-Num using the Error Code "Unknown
Object Class". Object Class".
An LSR that does not recognize a TLV type code carried in this object An LSR that does not recognize a TLV type code carried in this object
MUST reject the Path message using a PathErr with Error Code MUST reject the Path message using a PathErr with Error Code "Unknown
"Unknown Attributes TLV" and Error Value set to the value of the Attributes TLV" and Error Value set to the value of the unknown TLV
unknown TLV type code. type code.
An LSR that does not recognize a bit set in the Attributes Flags An LSR that does not recognize a bit set in the Attributes Flags TLV
TLV MUST reject the Path message using a PathErr with Error Code MUST reject the Path message using a PathErr with Error Code "Unknown
"Unknown Attributes Bit" and Error Value set to the bit number of Attributes Bit" and Error Value set to the bit number of the unknown
the unknown bit in the Attributes Flags. bit in the Attributes Flags.
An LSR that recognizes an attribute, however encoded, but which does An LSR that recognizes an attribute (however encoded), but that does
not support that attribute MUST act according to the behavior not support that attribute, MUST act according to the behavior
specified in the document that defines that specific attribute. specified in the document that defines that specific attribute.
Note that this object is not used on a Resv. In order to report the Note that this object is not used on a Resv. In order to report the
status of an LSP either the LSP_ATTRIBUTES object on a Resv or the status of an LSP, either the LSP_ATTRIBUTES object on a Resv or the
Attributes subobject in the Record Route object (see Section 7) must Attributes subobject in the Record Route object (see Section 7) must
be used. be used.
6. Inheritance Rules 6. Inheritance Rules
In certain circumstances, when reaching an LSP region boundary, a In certain circumstances, when reaching an LSP region boundary, a
FA-LSP (see [MPLS-HIER]) is initially setup to allow the forwarding adjacency LSP (FA-LSP; see [RFC4206]) is initially set up
establishment of the LSP carrying the LSP ATTRIBUTES and/or to allow the establishment of the LSP carrying the LSP_ATTRIBUTES
LSP_REQUIRED_ATTRIBUTES objects. In this case, when the boundary LSR and/or LSP_REQUIRED_ATTRIBUTES objects. In this case, when the
supports LSP_ATTRIBUTES and LSP_REQUIRED_ATTRIBUTES processing, the boundary LSR supports LSP_ATTRIBUTES and LSP_REQUIRED_ATTRIBUTES
FA-LSP MAY upon local policy inherit a subset of the Attributes TLVs, processing, the FA-LSP MAY upon local policy inherit a subset of the
in particular when the FA-LSP belongs to the same switching Attributes TLVs, in particular when the FA-LSP belongs to the same
capability class as the triggering LSP. switching capability class as the triggering LSP.
When these conditions are met, the LSP_ATTRIBUTES and/or When these conditions are met, the LSP_ATTRIBUTES and/or
LSP_REQUIRED_ATTRIBUTES objects are simply copied with the inherited LSP_REQUIRED_ATTRIBUTES objects are simply copied with the inherited
Attributes TLVs in the Path message used to establish the FA-LSP. By Attributes TLVs in the Path message used to establish the FA-LSP. By
default (and in order to simplify deployment), none of the incoming default (and in order to simplify deployment), none of the incoming
LSP Attributes TLV are considered as inheritable. Note that when the LSP Attributes TLVs are considered as inheritable. Note that when
FA-LSP establishment itself requires one or more Attributes TLVs, an the FA-LSP establishment itself requires one or more Attributes TLVs,
'OR' operation is performed with the inherited set of values. an 'OR' operation is performed with the inherited set of values.
Documents that define individual bits for the LSP Attributes Flags Documents that define individual bits for the LSP Attributes Flags
TLV MUST specify whether these bits MAY be inherited or not TLV MUST specify whether or not these bits MAY be inherited
(including the condition to be met in order for this inheritance to (including the condition to be met in order for this inheritance to
occur). The same applies for any other TLV that will be defined occur). The same applies for any other TLV that will be defined
following the rules specified in Section 3. following the rules specified in Section 3.
7. Recording Attributes Per-LSP 7. Recording Attributes Per LSP
7.1 Requirements 7.1. Requirements
In some circumstances it is useful to determine which of the In some circumstances, it is useful to determine which of the
requested LSP attributes have been applied at which LSRs along the requested LSP attributes have been applied at which LSRs along the
path of the LSP. For example, an attribute may be requested in the path of the LSP. For example, an attribute may be requested in the
LSP_ATTRIBUTES object such that LSRs that do not support the object LSP_ATTRIBUTES object such that LSRs that do not support the object
are not required to support the attribute or provide the requested are not required to support the attribute or provide the requested
function. In this case, it may be useful to the ingress LSR to know function. In this case, it may be useful to the ingress LSR to know
which LSRs acted on the request and which ignored it. which LSRs acted on the request and which ignored it.
Additionally, there may be other qualities that need to be reported Additionally, there may be other qualities that need to be reported
on a hop-by-hop basis. These are currently indicated in the Flags on a hop-by-hop basis. These are currently indicated in the Flags
field of RRO subobjects. Since there are only eight bits available field of RRO subobjects. Since there are only eight bits available
in this field, and since some are already assigned and there is also in this field, and since some are already assigned and there is also
likely to be an increase in allocations in new documents, there is a likely to be an increase in allocations in new documents, there is a
need for some other method to report per-hop attributes. need for some other method to report per-hop attributes.
7.2 RRO Attributes Subobject 7.2. RRO Attributes Subobject
The RRO Attributes Subobject may be carried in the RECORD_ROUTE The RRO Attributes Subobject may be carried in the RECORD_ROUTE
object if it is present. The subobject uses the standard format of object if it is present. The subobject uses the standard format of
an RRO subobject. an RRO subobject.
The length is variable as for the Attributes Flags TLV. The content The length is variable as for the Attributes Flags TLV. The content
is the same as the Attribute Flags TLV - that is, it is a series of is the same as the Attribute Flags TLV -- that is, it is a series of
bit flags. bit flags.
There is a one-to-one correspondence between bits in the Attributes There is a one-to-one correspondence between bits in the Attributes
Flags TLV and the RRO Attributes Subobject. If a bit is only required Flags TLV and the RRO Attributes Subobject. If a bit is only
in one of the two places, it is reserved in the other place. See required in one of the two places, it is reserved in the other place.
the procedures sections, below, for more information. See the procedures sections, below, for more information.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved | | Type | Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
// Attribute Flags // // Attribute Flags //
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
0x?? TBD by IANA RRO Attribute Subobject (see section 11.6). 0x05
Length Length
The Length contains the total length of the subobject in bytes, The Length contains the total length of the subobject in bytes,
including the Type and Length fields. This length must be a including the Type and Length fields. This length must be a
multiple of 4 and must be at least 8. multiple of 4 and must be at least 8.
Attribute Flags Attribute Flags
The attribute flags recorded for the specific hop. The attribute flags recorded for the specific hop.
7.3 Procedures 7.3. Procedures
7.3.1 Subobject Presence Rules 7.3.1. Subobject Presence Rules
As will be clear from [RFC3209], the RECORD_ROUTE object is managed As will be clear from [RFC3209], the RECORD_ROUTE object is managed
as a "stack" with each LSR adding sub-objects to the start of the as a "stack" with each LSR adding subobjects to the start of the
object. The Attributes subobject is pushed onto the RECORD_ROUTE object. The Attributes subobject is pushed onto the RECORD_ROUTE
object immediately prior to pushing the node's IP address or link object immediately prior to pushing the node's IP address or link
identifier. Thus, if label recording is being used, the Attributes identifier. Thus, if label recording is being used, the Attributes
subobject SHOULD be pushed onto the RECORD_ROUTE object after the subobject SHOULD be pushed onto the RECORD_ROUTE object after the
Record Label subobject(s). Record Label subobject(s).
A node MUST NOT push an Attributes subobject on to the RECORD_ROUTE A node MUST NOT push an Attributes subobject on to the RECORD_ROUTE
object without also pushing an IPv4, IPv6 or Unnumbered Interface ID object without also pushing an IPv4, IPv6, or Unnumbered Interface ID
subobject. subobject.
This means that an Attributes subobject is bound to the LSR This means that an Attributes subobject is bound to the LSR
identified by the subobject found in the RRO immediately before the identified by the subobject found in the RRO immediately before the
Attributes subobject. Attributes subobject.
If the new subobject causes the RRO to be too big to fit in a Path If the new subobject causes the RRO to be too big to fit in a Path
(or Resv) message, the processing MUST be as described in section (or Resv) message, the processing MUST be as described in Section
4.4.3 of [RFC3209]. 4.4.3 of [RFC3209].
If more than one Attributes subobject is found between a pair of If more than one Attributes subobject is found between a pair of
subobjects that identify LSRs, only the first one found (that is, the subobjects that identify LSRs, only the first one found (that is, the
nearest to the top of the stack) SHALL have any meaning within the nearest to the top of the stack) SHALL have any meaning within the
context of this document. All such subobjects MUST be forwarded context of this document. All such subobjects MUST be forwarded
unmodified by transit LSRs. unmodified by transit LSRs
7.3.2 Reporting Compliance with LSP Attributes 7.3.2. Reporting Compliance with LSP Attributes
To report compliance with an attribute requested in the Attributes To report compliance with an attribute requested in the Attributes
Flags TLV, an LSR MAY set the corresponding bit (see Section 8) in Flags TLV, an LSR MAY set the corresponding bit (see Section 8) in
the Attributes subobject. To report non-compliance, an LSR MAY clear the Attributes subobject. To report non-compliance, an LSR MAY clear
the corresponding bit in the Attributes subobject. the corresponding bit in the Attributes subobject.
The requirement to report compliance MUST be specified in the The requirement to report compliance MUST be specified in the
document that defines the usage of any bit. This will reduce to a document that defines the usage of any bit. This will reduce to a
statement of whether hop-by-hop acknowledgement is required. statement of whether hop-by-hop acknowledgement is required.
7.3.3 Reporting Per-Hop Attributes 7.3.3. Reporting Per-Hop Attributes
To report a per-hop attribute, an LSR sets the appropriate bit in the To report a per-hop attribute, an LSR sets the appropriate bit in the
Attributes subobject. Attributes subobject.
The requirement to report a per-hop attribute MUST be specified in The requirement to report a per-hop attribute MUST be specified in
the document that defines the usage of the bit. the document that defines the usage of the bit.
7.3.4 Default Behavior 7.3.4. Default Behavior
By default all bits in an Attributes subobject SHOULD be set to zero. By default, all bits in an Attributes subobject SHOULD be set to
zero.
If a received Attribute subobject is not long enough to include a If a received Attribute subobject is not long enough to include a
specific numbered bit, that bit MUST be treated as though present and specific numbered bit, that bit MUST be treated as though present and
as if set to zero. as if set to zero.
If the RRO subobject is not present for a hop in the LSP, all bits If the RRO subobject is not present for a hop in the LSP, all bits
MUST be assumed to be set to zero. MUST be assumed to be set to zero.
8. Summary of Attribute Bit Allocation 8. Summary of Attribute Bit Allocation
skipping to change at line 632 skipping to change at page 14, line 18
9. Message Formats 9. Message Formats
The LSP_ATTRIBUTES object and the LSP_REQUIRED_ATTRIBUTES object MAY The LSP_ATTRIBUTES object and the LSP_REQUIRED_ATTRIBUTES object MAY
be carried in a Path message. The LSP_ATTRIBUTES object MAY be be carried in a Path message. The LSP_ATTRIBUTES object MAY be
carried in a Resv message. carried in a Resv message.
The order of objects in RSVP-TE messages is recommended, but The order of objects in RSVP-TE messages is recommended, but
implementations must be capable of receiving the objects in any implementations must be capable of receiving the objects in any
meaningful order. meaningful order.
On a Path message, the LSP_ATTRIBUTES object and LSP_REQUIRED_ On a Path message, the LSP_ATTRIBUTES object and
ATTRIBUTES objects are RECOMMENDED to be placed immediately after the LSP_REQUIRED_ATTRIBUTES objects are RECOMMENDED to be placed
SESSION_ATTRIBUTE object if it is present, or otherwise immediately immediately after the SESSION_ATTRIBUTE object if it is present, or
after the LABEL_REQUEST object. otherwise immediately after the LABEL_REQUEST object.
If both the LSP_ATTRIBUTES object and the LSP_REQUIRED_ATTRIBUTES If both the LSP_ATTRIBUTES object and the LSP_REQUIRED_ATTRIBUTES
object are present, the LSP_REQUIRED_ATTRIBUTES object is RECOMMENDED object are present, the LSP_REQUIRED_ATTRIBUTES object is RECOMMENDED
to be placed first. to be placed first.
LSRs MUST be prepared to receive these objects in any order in any LSRs MUST be prepared to receive these objects in any order in any
position within a Path message. Subsequent instances of these objects position within a Path message. Subsequent instances of these
within a Path message SHOULD be ignored and those objects MUST be objects within a Path message SHOULD be ignored and those objects
forwarded unchanged. MUST be forwarded unchanged.
On a Resv message, the LSP_ATTRIBUTES object is placed in the flow On a Resv message, the LSP_ATTRIBUTES object is placed in the flow
descriptor and is associated with the FILTER_SPEC object that descriptor and is associated with the FILTER_SPEC object that
precedes it. It is RECOMMENDED that the LSP_ATTRIBUTES object be precedes it. It is RECOMMENDED that the LSP_ATTRIBUTES object be
placed immediately after the LABEL object. placed immediately after the LABEL object.
LSRs MUST be prepared to receive this object in any order in any LSRs MUST be prepared to receive this object in any order in any
position within a Resv message subject to the previous note. Only position within a Resv message subject to the previous note. Only
one instance of the LSP_ATTRIBUTES object is meaningful within the one instance of the LSP_ATTRIBUTES object is meaningful within the
context of a FILTER_SPEC object. Subsequent instances of the object context of a FILTER_SPEC object. Subsequent instances of the object
SHOULD be ignored and MUST be forwarded unchanged. SHOULD be ignored and MUST be forwarded unchanged.
10. Guidance for Key Application Scenarios 10. Guidance for Key Application Scenarios
As described in the Introduction section of this document, it may be As described in the Introduction section of this document, it may be
that requested LSP attributes need to be acted on by only the egress that requested LSP attributes need to be acted on by only the egress
LSR of the LSP, by certain key transit points (such as ABRs and LSR of the LSP, by certain key transit points (such as ABRs and
ASBRs) or by all LSRs along the LSP. This section briefly describes ASBRs), or by all LSRs along the LSP. This section briefly describes
how each of these scenarios is met. This section is informational and how each of these scenarios is met. This section is informational
does not define any new procedures. and does not define any new procedures.
10.1. Communicating to Egress LSRs 10.1. Communicating to Egress LSRs
When communicating LSP attributes that must be acted on only by the When communicating LSP attributes that must be acted on only by the
LSP egress LSR, the attributes should be communicated in the LSP egress LSR, the attributes should be communicated in the
LSP_ATTRIBUTES object. Because of its C-Num, this object may be LSP_ATTRIBUTES object. Because of its C-Num, this object may be
ignored (passed onwards, untouched) by transit LSRs that do not ignored (passed onwards, untouched) by transit LSRs that do not
understand it. This means that the Path message will not be rejected understand it. This means that the Path message will not be rejected
by LSRs that do not understand the object. In this way, the requested by LSRs that do not understand the object. In this way, the
LSP attributes are guaranteed to reach the egress LSR. requested LSP attributes are guaranteed to reach the egress LSR.
Attributes are set within the LSP_ATTRIBUTES object according to Attributes are set within the LSP_ATTRIBUTES object according to
which LSP attributes are required. Each attribute is defined in some which LSP attributes are required. Each attribute is defined in some
RFC and is accompanied by a statement of what the expected behavior RFC and is accompanied by a statement of what the expected behavior
is. This behavior will include whether the attribute must be acted on is. This behavior will include whether the attribute must be acted
by any LSR that recognises it, or specifically by the egress LSR. on by any LSR that recognizes it, or specifically by the egress LSR.
Thus any attribute that must be acted on only by an egress LSR will Thus, any attribute that must be acted on only by an egress LSR will
be defined in this way - any transit LSR seeing this attribute will be defined in this way -- any transit LSR seeing this attribute
either understand the semantics of the attribute and ignore it either will understand the semantics of the attribute and ignore it
(forwarding it, unchanged), or will not understand the attribute and (forwarding it, unchanged) or will not understand the attribute and
will ignore it (forwarding it, unchanged) according to the rules of ignore it (forwarding it, unchanged) according to the rules of the
the LSP_ATTRIBUTES object. LSP_ATTRIBUTES object.
The remaining issue is how the ingress LSR can know whether the The remaining issue is how the ingress LSR can know whether the
egress LSR has acted correctly on the required LSP attribute. Another egress LSR has acted correctly on the required LSP attribute.
part of the definition of the attribute (in the defining RFC) is Another part of the definition of the attribute (in the defining RFC)
whether reporting is required. If reporting is required, the egress is whether reporting is required. If reporting is required, the
LSR is required to use the RRO Attributes subobject to report whether egress LSR is required to use the RRO Attributes subobject to report
it has acted on the received attribute. whether it has acted on the received attribute.
If an egress LSR understands a received attribute as mandatory for an If an egress LSR understands a received attribute as mandatory for an
egress LSR, but does not wish to satisfy the request, it will reject egress LSR, but does not wish to satisfy the request, it will reject
the Path message. If an egress LSR understands the attribute, but the Path message. If an egress LSR understands the attribute, but
believes it to be optional and does not wish to satisfy the request, believes it to be optional and does not wish to satisfy the request,
it will report its non-compliance in the RRO Attributes subobject. If it will report its non-compliance in the RRO Attributes subobject.
the egress LSR does not understand the received attribute, it may If the egress LSR does not understand the received attribute, it may
report non-compliance in the RRO Attributes subobject explicitly, or report non-compliance in the RRO Attributes subobject explicitly, or
may omit the RRO Attributes subobject implying that it has not may omit the RRO Attributes subobject implying that it has not
satisfied the request. satisfied the request.
10.2. Communicating to Key Transit LSRs 10.2. Communicating to Key Transit LSRs
Processing for key transit LSRs (such as ABRs and ASBRs) follows Processing for key transit LSRs (such as ABRs and ASBRs) follows
exactly as for egress LSR. The only difference is that the definition exactly as for egress LSR. The only difference is that the
of the LSP attribute in the defining RFC will state that the definition of the LSP attribute in the defining RFC will state that
attribute must be acted on by these transit LSRs. the attribute must be acted on by these transit LSRs.
10.3. Communicating to All LSRs 10.3. Communicating to All LSRs
In order to force all LSRs to examine the LSP attributes, the In order to force all LSRs to examine the LSP attributes, the
LSP_REQUIRED_ATTRIBUTES object is used. The C-Num of this object is LSP_REQUIRED_ATTRIBUTES object is used. The C-Num of this object is
such that any LSR that does not recognise the object must reject a such that any LSR that does not recognize the object must reject a
received Path message containing the object. received Path message containing the object.
An LSR that recognises the LSP_REQUIRED_ATTRIBUTES object, but that An LSR that recognizes the LSP_REQUIRED_ATTRIBUTES object, but does
does not recognize an attributes will reject the Path message. not recognize an attribute, will reject the Path message.
An LSR that recognizes an attribute, but which does not wish to An LSR that recognizes an attribute, but does not wish to support the
support the attribute reacts according to the definition of the attribute, reacts according to the definition of the attribute in the
attribute in the defining RFC. This may allow the LSR to ignore the defining RFC. This may allow the LSR to ignore the attribute and
attribute and forward it unchanged, or may require it to fail the LSP forward it unchanged, or may require it to fail the LSP setup. The
setup. The LSR may additionally be required to report whether it LSR may additionally be required to report whether it supports the
supports the attribute using the RRO Attributes subobject. attribute using the RRO Attributes subobject.
11. IANA Considerations 11. IANA Considerations
11.1 New RSVP C-Nums and C-Types 11.1. New RSVP C-Nums and C-Types
Two new RSVP C-Nums are defined in this document and should be Two new RSVP C-Nums are defined in this document and have been
assigned by IANA. assigned by IANA.
o LSP_ATTRIBUTES object o LSP_ATTRIBUTES object
The C-Num should be of the form 11bbbbbb so that LSRs that do not The C-Num (value 197) is of the form 11bbbbbb so that LSRs that do
recognize the object will ignore the object but forward it, not recognize the object will ignore the object but forward it,
unexamined and unmodified, in all messages resulting from this unexamined and unmodified, in all messages resulting from this
message. message.
One C-Type is defined for this object and should be assigned by One C-Type is defined for this object and has been assigned by
IANA. IANA.
o LSP Attributes TLVs o LSP Attributes TLVs
Recommended C-Type value 1. Recommended C-Type value 1.
o LSP_REQUIRED_ATTRIBUTES object o LSP_REQUIRED_ATTRIBUTES object
The C-Num should be of the form 0bbbbbbb so that LSRs that do not The C-Num (value 67) is of the form 0bbbbbbb so that LSRs that do
recognize the object will reject the message that carries it with not recognize the object will reject the message that carries it
an "Unknown Object Class" error. with an "Unknown Object Class" error.
One C-Type is defined for this object and should be assigned by One C-Type is defined for this object and has been assigned by
IANA. IANA.
o LSP Required Attributes TLVs o LSP Required Attributes TLVs
Recommended C-Type value 1. Recommended C-Type value 1.
11.2 New TLV Space 11.2. New TLV Space
The two new objects referenced above are constructed from TLVs. Each The two new objects referenced above are constructed from TLVs. Each
TLV includes a 16-bit type identifier (the T-field). The same T-field TLV includes a 16-bit type identifier (the T-field). The same
values are applicable to both objects. T-field values are applicable to both objects.
IANA is requested to manage TLV type identifiers as follows: The IANA has created a new registry and will manage TLV type
identifiers as follows:
- TLV Type (T-field value) - TLV Type (T-field value)
- TLV Name - TLV Name
- Whether allowed on LSP_ATTRIBUTES object - Whether allowed on LSP_ATTRIBUTES object
- Whether allowed on LSP_REQUIRED_ATTRIBUTES object. - Whether allowed on LSP_REQUIRED_ATTRIBUTES object.
This document defines one TLV type as follows: This document defines one TLV type as follows:
- TLV Type = 1 - TLV Type = 1
- TLV Name = Attributes Flags TLV - TLV Name = Attributes Flags TLV
- allowed on LSP_ATTRIBUTES object - allowed on LSP_ATTRIBUTES object
- allowed on LSP_REQUIRED_ATTRIBUTES object. - allowed on LSP_REQUIRED_ATTRIBUTES object.
New TLV type values may be allocated only by an IETF Consensus New TLV type values may be allocated only by an IETF Consensus
action. action.
11.3 Attributes Flags 11.3. Attributes Flags
This document provides new attributes bit flags for use in other This document provides new attributes bit flags for use in other
documents that specify new RSVP-TE attributes. These flags are documents that specify new RSVP-TE attributes. These flags are
present in the Attributes Flags TLV referenced in the previous present in the Attributes Flags TLV referenced in the previous
section. section.
IANA is requested to manage the space of attributes bit flags The IANA has created a new registry and will manage the space of
numbering them in the usual IETF notation starting at zero and attributes bit flags numbering them in the usual IETF notation
continuing at least through 31. starting at zero and continuing at least through 31.
New bit numbers may be allocated only by an IETF Consensus action. New bit numbers may be allocated only by an IETF Consensus action.
Each bit should be tracked with the following qualities: Each bit should be tracked with the following qualities:
- Bit number - Bit number
- Defining RFC - Defining RFC
- Name of bit - Name of bit
- Whether there is meaning in the Attribute Flags TLV on a Path - Whether there is meaning in the Attribute Flags TLV on a Path
- Whether there is meaning in the Attribute Flags TLV on a Resv - Whether there is meaning in the Attribute Flags TLV on a Resv
- Whether there is meaning in the RRO Attributes Subobject. - Whether there is meaning in the RRO Attributes Subobject.
Note that this means that all bits in the Attribute Flags TLV and the Note that this means that all bits in the Attribute Flags TLV and the
RRO Attributes Subobject use the same bit number regardless of RRO Attributes Subobject use the same bit number regardless of
whether they are used in one or both places. Thus, only one list of whether they are used in one or both places. Thus, only one list of
skipping to change at line 810 skipping to change at page 18, line 10
- Defining RFC - Defining RFC
- Name of bit - Name of bit
- Whether there is meaning in the Attribute Flags TLV on a Path - Whether there is meaning in the Attribute Flags TLV on a Path
- Whether there is meaning in the Attribute Flags TLV on a Resv - Whether there is meaning in the Attribute Flags TLV on a Resv
- Whether there is meaning in the RRO Attributes Subobject. - Whether there is meaning in the RRO Attributes Subobject.
Note that this means that all bits in the Attribute Flags TLV and the Note that this means that all bits in the Attribute Flags TLV and the
RRO Attributes Subobject use the same bit number regardless of RRO Attributes Subobject use the same bit number regardless of
whether they are used in one or both places. Thus, only one list of whether they are used in one or both places. Thus, only one list of
bits is required to be maintained. (It would be meaningless in the bits is required to be maintained. (It would be meaningless in the
context of this document for a bit to have no meaning in neither the context of this document for a bit to have no meaning in either the
Attribute Flags TLV nor the RRO Attributes Subobject.) Attribute Flags TLV or the RRO Attributes Subobject.)
11.4 SESSION_ATTRIBUTE Flags Field
This document does not make any alterations to the definition of the
existing SESSION_ATTRIBUTE object nor to the definition of meanings
assigned to the flags in the Flags field of that object. These flags
are assigned meanings in various other RFCs and Internet Drafts.
It is suggested that IANA manage the allocation of meaning to the
bits in the Flags field of the SESSION_ATTRIBUTE object to prevent
accidental double allocation of any one bit.
It is suggested that new SESSION_ATTRIBUTE Flags be allocated only by
an IETF Consensus action.
11.5 New Error Codes 11.4. New Error Codes
This document defines the following new error codes and error values. This document defines the following new Error Codes and Error Values.
Numeric values should be assigned by IANA. Numeric values have been assigned by IANA.
Error Code Error Value Error Code Error Value
"Unknown Attributes TLV" Identifies the unknown TLV type code. 29 "Unknown Attributes TLV" Identifies the unknown TLV type code.
"Unknown Attributes Bit" Identifies the unknown Attribute Bit. 30 "Unknown Attributes Bit" Identifies the unknown Attribute Bit.
11.6 New Record Route Subobject Identifier 11.5. New Record Route Subobject Identifier
A new subobject is defined for inclusion in the RECORD_ROUTE object. A new subobject is defined for inclusion in the RECORD_ROUTE object.
The RRO Attributes subobject is identified by a Type value of TBD. The RRO Attributes subobject is identified by a Type value of 5.
12. Security Considerations 12. Security Considerations
This document adds two new objects to the RSVP Path message as used This document adds two new objects to the RSVP Path message as used
in MPLS and GMPLS signaling, and a new subobject to the RECORD_ROUTE in MPLS and GMPLS signaling, and a new subobject to the RECORD_ROUTE
object carried on may RSVP messages. It does not introduce any new object carried on many RSVP messages. It does not introduce any new
direct security issues and the reader is referred to the security direct security issues, and the reader is referred to the security
considerations expressed in [RFC2205], [RFC3209] and [RFC3473]. considerations expressed in [RFC2205], [RFC3209], and [RFC3473].
It is of passing note that any signaling request that indicates the It is of passing note that any signaling request that indicates the
functional preferences or attributes of an MPLS LSP may provide functional preferences or attributes of an MPLS LSP may provide
anyone with unauthorized access to the contents of the message with anyone with unauthorized access to the contents of the message with
information about the LSP that an administrator may wish to keep information about the LSP that an administrator may wish to keep
secret. Although this document adds new objects for signaling desired secret. Although this document adds new objects for signaling
LSP attributes, it does not contribute to this issue which can desired LSP attributes, it does not contribute to this issue, which
only be satisfactorily handled by encrypting the content of the can only be satisfactorily handled by encrypting the content of the
signaling message. signaling message.
Similarly, the addition of attribute recording information to the Similarly, the addition of attribute recording information to the RRO
RRO may reveal information about the status of the LSP and the may reveal information about the status of the LSP and the
capabilities of individual LSRs that operators wish to keep secret. capabilities of individual LSRs that operators wish to keep secret.
The same strategy that applies to other RRO subobjects also applies The same strategy that applies to other RRO subobjects also applies
here. Note, however, that there is a tension between notifying the here. Note, however, that there is a tension between notifying the
head end of the LSP status at transit LSRs, and hiding the existence head end of the LSP status at transit LSRs, and hiding the existence
or identity of the transit LSRs. or identity of the transit LSRs.
13. Acknowledgements 13. Acknowledgements
Credit to the OSPF Working Group for inspiration from their solution Credit to the OSPF Working Group for inspiration from their solution
to a similar problem. Thanks to Rahul Aggarwal for his careful review to a similar problem. Thanks to Rahul Aggarwal for his careful
and support of this work. Thanks also to Raymond Zhang, Kireeti review and support of this work. Thanks also to Raymond Zhang,
Kompella, Philip Matthews, Jim Gibson and Alan Kullberg for their Kireeti Kompella, Philip Matthews, Jim Gibson, and Alan Kullberg for
input. As so often, thanks to John Drake for useful offline their input. As so often, thanks to John Drake for useful offline
discussions. Thanks to Mike Shand for providing the Routing discussions. Thanks to Mike Shand for providing the Routing
Directorate review and to Joel Halpern for the General Area review - Directorate review and to Joel Halpern for the General Area review --
both picked up on some unclarities. both picked up on some unclarities.
14. Intellectual Property Consideration 14. Normative References
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at ietf-
ipr@ietf.org.
15. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2205] Braden, R. (Ed.), Zhang, L., Berson, S., Herzog, S. [RFC2205] Braden, R. (Ed.), Zhang, L., Berson, S., Herzog, S., and
and S. Jamin, "Resource ReserVation Protocol -- S. Jamin, "Resource ReSerVation Protocol (RSVP) --
Version 1 Functional Specification", RFC 2205, Version 1 Functional Specification", RFC 2205, September
September 1997. 1997.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T.,
Srinivasan, V. and G. Swallow, "RSVP-TE: Extensions
to RSVP for LSP Tunnels", RFC 3209, December 2001.
[RFC3471] Berger, L. (Editor), "Generalized Multi-Protocol Label [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
Switching (GMPLS) Signaling Functional Description", and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
RFC 3471, January 2003. Tunnels", RFC 3209, December 2001.
[RFC3473] Berger, L. (Editor), "Generalized MPLS Signaling - [RFC3471] Berger, L. (Ed.), "Generalized Multi-Protocol Label
RSVP-TE Extensions", RFC 3473 January 2003. Switching (GMPLS) Signaling Functional Description", RFC
3471, January 2003.
16. Informative References [RFC3473] Berger, L. (Ed.), "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Resource ReserVation
Protocol-Traffic Engineering (RSVP-TE) Extensions", RFC
3473, January 2003.
[RFC2026] Bradner, S., "The Internet Standards Process 15. Informative References
-- Revision 3", RFC 2026, October 1996.
[RFC3031] Rosen, E., Viswanathan, A., and Callon, R., [RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
"Multiprotocol Label Switching Label Switching Architecture", RFC 3031, January 2001.
Architecture", RFC 3031, January 2001.
[FRR] Pan, P. (Ed.), "Fast Reroute Extensions to RSVP-TE for [RFC4090] Pan, P., Swallow, G., and A. Atlas, "Fast Reroute
LSP Tunnels", draft-ietf-mpls-rsvp-lsp-fastreroute, Extensions to RSVP-TE for LSP Tunnels", RFC 4090, May
work in progress. 2005.
[MPLS-HIER] Kompella, K. and Y. Rekhter, "LSP Hierarchy with [RFC4206] Kompella, K. and Y. Rekhter, "Label Switched Paths (LSP)
MPLS TE", draft-ietf-mpls-lsp-hierarchy, work in Hierarchy with Generalized Multi-Protocol Label Switching
progress. (GMPLS) Traffic Engineering (TE)", RFC 4206, October
2005.
17. Authors' Addresses Authors' Addresses
Adrian Farrel Adrian Farrel
Old Dog Consulting Old Dog Consulting
Phone: +44 (0) 1978 860944 Phone: +44 (0) 1978 860944
EMail: adrian@olddog.co.uk EMail: adrian@olddog.co.uk
Dimitri Papadimitriou (Alcatel) Dimitri Papadimitriou
Alcatel
Fr. Wellesplein 1, Fr. Wellesplein 1,
B-2018 Antwerpen, Belgium B-2018 Antwerpen, Belgium
Phone: +32 3 240-8491 Phone: +32 3 240-8491
EMail: dimitri.papadimitriou@alcatel.be EMail: dimitri.papadimitriou@alcatel.be
Jean Philippe Vasseur Jean Philippe Vasseur
Cisco Systems, Inc. Cisco Systems, Inc.
300 Beaver Brook Road 1414 Massachusetts Avenue
Boxborough , MA - 01719 Boxborough , MA - 01719
USA USA
EMail: jpv@cisco.com EMail: jpv@cisco.com
Arthi Ayyangar Arthi Ayyangar
Juniper Networks, Inc. Juniper Networks, Inc.
1194 N.Mathilda Ave 1194 N.Mathilda Ave
Sunnyvale, CA 94089 Sunnyvale, CA 94089
USA USA
EMail: arthi@juniper.net EMail: arthi@juniper.net
18. Disclaimer of Validity Full Copyright Statement
Copyright (C) The Internet Society (2006).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
19. Full Copyright Statement Intellectual Property
Copyright (C) The Internet Society (2005). This document is subject The IETF takes no position regarding the validity or scope of any
to the rights, licenses and restrictions contained in BCP 78, and Intellectual Property Rights or other rights that might be claimed to
except as set forth therein, the authors retain all their rights. pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.
Acknowledgement
Funding for the RFC Editor function is provided by the IETF
Administrative Support Activity (IASA).
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