--- 1/draft-ietf-mpls-cr-ldp-05.txt 2006-02-05 00:37:41.000000000 +0100 +++ 2/draft-ietf-mpls-cr-ldp-06.txt 2006-02-05 00:37:41.000000000 +0100 @@ -1,84 +1,85 @@ MPLS Working Group Bilel Jamoussi, Editor Internet Draft Nortel Networks Corp. -Expiration Date: August 2001 +Expiration Date: May 2002 - O. Aboul-Magd, L. Andersson, P. Ashwood-Smith, + O. Aboul-Magd, P. Ashwood-Smith, F. Hellstrand, K. Sundell, Nortel Networks Corp. + L. Andersson, Utfors R. Callon, Juniper Networks. R. Dantu, L. Wu, Cisco Systems P. Doolan, T. Worster, Ennovate Networks Corp. N. Feldman, IBM Corp. A. Fredette, PhotonEx Corp. M. Girish, Atoga Systems E. Gray, Sandburst J. Halpern, Longitude Systems, Inc. J. Heinanen, Telia Finland T. Kilty, Newbridge Networks, Inc. A. Malis, Vivace Networks P. Vaananen, Nokia Telecommunications - February 2001 + November 2001 Constraint-Based LSP Setup using LDP - draft-ietf-mpls-cr-ldp-05.txt + draft-ietf-mpls-cr-ldp-06.txt Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference - material or to cite them other than as "work in progress.ö + material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Abstract Label Distribution Protocol (LDP) is defined in [1] for distribution of labels inside one MPLS domain. One of the most important services that may be offered using MPLS in general and LDP in particular is support for constraint-based routing of traffic across -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 1 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 1 the routed network. Constraint-based routing offers the opportunity to extend the information used to setup paths beyond what is available for the routing protocol. For instance, an LSP can be setup based on explicit route constraints, QoS constraints, and other constraints. Constraint-based routing (CR) is a mechanism used to meet Traffic Engineering requirements that have been proposed by, [2] and [3]. These requirements may be met by extending LDP for support of constraint-based routed label switched paths (CR-LSPs). Other uses for CR-LSPs include MPLS-based VPNs [4]. More information about the applicability of CR-LDP can be found in [5]. This draft specifies mechanisms and TLVs for support of CR-LSPs using LDP. The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [6]. -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 2 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 2 Table of Contents 1. Introduction....................................................4 2. Constraint-based Routing Overview...............................4 2.1 Strict and Loose Explicit Routes...............................5 2.2 Traffic Characteristics........................................5 2.3 Pre-emption....................................................6 2.4 Route Pinning..................................................6 2.5 Resource Class.................................................6 3. Solution Overview...............................................6 @@ -117,23 +118,23 @@ 4.9 Route Pinning TLV.............................................25 4.10 CR-LSP FEC Element...........................................26 5. IANA Considerations............................................26 5.1 TLV Type Name Space...........................................26 5.2 FEC Type Name Space...........................................27 5.3 Status Code Space.............................................27 6. Security.......................................................28 7. Acknowledgments................................................28 8. Intellectual Property Consideration............................28 -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 3 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 3 9. References.....................................................28 - 10. AuthorÆs Addresses............................................29 + 10. Author's Addresses............................................29 Appendix A: CR-LSP Establishment Examples.........................31 A.1 Strict Explicit Route Example.................................31 A.2 Node Groups and Specific Nodes Example........................32 Appendix B. QoS Service Examples..................................35 B.1 Service Examples..............................................35 B.2 Establishing CR-LSP Supporting Real-Time Applications.........36 B.3 Establishing CR-LSP Supporting Delay Insensitive Applications.37 1. Introduction @@ -170,21 +171,21 @@ of CR-LSP path setup. Appendix B provides Service Definition Examples. 2. Constraint-based Routing Overview Constraint-based routing is a mechanism that supports the Traffic Engineering requirements defined in [3]. Explicit Routing is a subset of the more general constraint-based routing where the constraint is the explicit route (ER). Other constraints are defined -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 4 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 4 to provide a network operator with control over the path taken by an LSP. This section is an overview of the various constraints supported by this specification. Like any other LSP a CR-LSP is a path through an MPLS network. The difference is that while other paths are setup solely based on information in routing tables or from a management system, the constraint-based route is calculated at one point at the edge of network based on criteria, including but not limited to routing information. The intention is that this functionality shall give @@ -222,23 +223,23 @@ including all of the abstract nodes, with the specified operations occurring along that path. 2.2 Traffic Characteristics The traffic characteristics of a path are described in the Traffic Parameters TLV in terms of a peak rate, committed rate, and service granularity. The peak and committed rates describe the bandwidth constraints of a path while the service granularity can be used to specify a constraint on the delay variation that the CR-LDP MPLS - domain may introduce to a pathÆs traffic. + domain may introduce to a path's traffic. -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 5 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 5 2.3 Pre-emption CR-LDP signals the resources required by a path on each hop of the route. If a route with sufficient resources can not be found, existing paths may be rerouted to reallocate resources to the new path. This is the process of path pre-emption. Setup and holding priorities are used to rank existing paths (holding priority) and the new path (setup priority) to determine if the new path can pre- empt an existing path. @@ -257,41 +258,41 @@ The setup and holding priority values range from zero (0) to seven (7). The value zero (0) is the priority assigned to the most important path. It is referred to as the highest priority. Seven (7) is the priority for the least important path. The use of default priority values is an aspect of network policy. The recommended default value is (4). The setupPriority of a CR-LSP should not be higher (numerically less) than its holdingPriority since it might bump an LSP and be - bumped by the next "equivalentö request. + bumped by the next "equivalent" request. 2.4 Route Pinning Route pinning is applicable to segments of an LSP that are loosely routed - i.e. those segments which are specified with a next hop - with the öLö bit set or where the next hop is an öabstract nodeö. A + with the "L" bit set or where the next hop is an "abstract node". A CR-LSP may be setup using route pinning if it is undesirable to change the path used by an LSP even when a better next hop becomes available at some LSR along the loosely routed portion of the LSP. 2.5 Resource Class The network operator may classify network resources in various ways. - These classes are also known as "colorsö or "administrative groupsö. - When a CR-LSP is being established, itÆs necessary to indicate which + These classes are also known as "colors" or "administrative groups". + When a CR-LSP is being established, it's necessary to indicate which resource classes the CR-LSP can draw from. 3. Solution Overview -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 6 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 6 CR-LSP over LDP Specification is designed with the following goals: 1. Meet the requirements outlined in [3] for performing traffic engineering and provide a solid foundation for performing more general constraint-based routing. 2. Build on already specified functionality that meets the requirements whenever possible. Hence, this specification is based on [1]. @@ -307,56 +308,57 @@ - Use of Basic and/or Extended Discovery Mechanisms. - Use of the Label Request Message defined in [1] in downstream on demand label advertisement mode with ordered control. - Use of the Label Mapping Message defined in [1] in downstream on demand mode with ordered control. - Use of the Notification Message defined in [1]. - Use of the Withdraw and Release Messages defined in [1]. - Use of the Loop Detection (in the case of loosely routed segments of a CR-LSP) mechanisms defined in [1]. - In addition, the following functionality is added to whatÆs defined + In addition, the following functionality is added to what's defined in [1]: - The Label Request Message used to setup a CR-LSP includes one or more CR-TLVs defined in Section 4. For instance, the Label Request Message may include the ER-TLV. - An LSR implicitly infers ordered control from the existence of one or more CR-TLVs in the Label Request Message. This means that the LSR can still be configured for independent control for LSPs established as a result of dynamic routing. However, when a Label Request Message includes one or more of the CR-TLVs, then ordered control is used to setup the CR-LSP. Note that this is also true for the loosely routed parts of a CR-LSP. - New status codes are defined to handle error notification for - failure of established paths specified in the CR-TLVs. + failure of established paths specified in the CR-TLVs. All of the + new status codes require that the F bit be set. Optional TLVs MUST be implemented to be compliant with the protocol. However, they are optionally carried in the CR-LDP messages to signal certain characteristics of the CR-LSP being established or modified. -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 7 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 7 Examples of CR-LSP establishment are given in Appendix A to illustrate how the mechanisms described in this draft work. 3.1 Required Messages and TLVs Any Messages, TLVs, and procedures not defined explicitly in this document are defined in the LDP Specification [1]. The reader can use [7] as an informational document about the state transitions, which relate to CR-LDP messages. The following subsections are meant as a cross-reference to the [1] - document and indication of additional functionality beyond whatÆs + document and indication of additional functionality beyond what's defined in [1] where necessary. Note that use of the Status TLV is not limited to Notification messages as specified in Section 3.4.6 of [1]. A message other than a Notification message may carry a Status TLV as an Optional Parameter. When a message other than a Notification carries a Status TLV the U-bit of the Status TLV should be set to 1 to indicate that the receiver should silently discard the TLV if unprepared to handle it. @@ -384,21 +386,21 @@ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| Label Request (0x0401) | Message Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Message ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | FEC TLV | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LSPID TLV (CR-LDP, mandatory) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 8 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 8 | ER-TLV (CR-LDP, optional) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Traffic TLV (CR-LDP, optional) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Pinning TLV (CR-LDP, optional) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Resource Class TLV (CR-LDP, optional) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Pre-emption TLV (CR-LDP, optional) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ @@ -437,31 +439,32 @@ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Label Request Message ID TLV | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LSPID TLV (CR-LDP, optional) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Traffic TLV (CR-LDP, optional) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3.4 Notification Message -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 9 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 9 The Notification Message is as defined in Section 3.5.1 of [1] and the Status TLV encoding is as defined in Section 3.4.6 of [1]. Establishment of an CR-LSP may fail for a variety of reasons. All such failures are considered advisory conditions and they are signaled by the Notification Message. Notification Messages carry Status TLVs to specify events being signaled. New status codes are defined in Section 4.11 to signal error notifications associated with the establishment of a CR-LSP - and the processing of the CR-TLV. + and the processing of the CR-TLV. All of the new status codes + require that the F bit be set. The Notification Message MAY carry the LSPID TLV of the corresponding CR-LSP. Notification Messages MUST be forwarded toward the LSR originating the Label Request at each hop and at any time that procedures in this specification - or in [1] - specify sending of a Notification Message in response to a Label Request Message. The encoding of the notification message is as follows: @@ -491,21 +494,21 @@ TLVs (CR-TLVs) defined in this section. If needed, other constraints can be supported later through the definition of new TLVs. In this specification, the following TLVs are defined: - Explicit Route TLV - Explicit Route Hop TLV - Traffic Parameters TLV - Preemption TLV - LSPID TLV -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 10 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 10 - Route Pinning TLV - Resource Class TLV - CR-LSP FEC TLV 4.1 Explicit Route TLV (ER-TLV) The ER-TLV is an object that specifies the path to be taken by the LSP being established. It is composed of one or more Explicit Route Hop TLVs (ER-Hop TLVs) defined in Section 4.2. @@ -533,55 +536,55 @@ ER-Hop TLVs One or more ER-Hop TLVs defined in Section 4.2. 4.2 Explicit Route Hop TLV (ER-Hop TLV) The contents of an ER-TLV are a series of variable length ER-Hop TLVs. A node receiving a label request message including an ER-Hop type that is not supported MUST not progress the label request message to - the downstream LSR and MUST send back a "No Routeö Notification + the downstream LSR and MUST send back a "No Route" Notification Message. Each ER-Hop TLV has the form: 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|0| Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |L| Content // | -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 11 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 11 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ER-Hop Type A fourteen-bit field carrying the type of the ER-Hop contents. Currently defined values are: Value Type ------ ------------------------ 0x0801 IPv4 prefix 0x0802 IPv6 prefix 0x0803 Autonomous system number 0x0804 LSPID Length Specifies the length of the value field in bytes. L bit The L bit in the ER-Hop is a one-bit attribute. If the L bit - is set, then the value of the attribute is "loose.ö Otherwise, - the value of the attribute is "strict.ö For brevity, we say + is set, then the value of the attribute is "loose." Otherwise, + the value of the attribute is "strict." For brevity, we say that if the value of the ER-Hop attribute is loose then it is a - "loose ER-Hop.ö Otherwise, itÆs a "strict ER-Hop.ö Further, + "loose ER-Hop." Otherwise, it's a "strict ER-Hop." Further, we say that the abstract node of a strict or loose ER-Hop is a strict or a loose node, respectively. Loose and strict nodes are always interpreted relative to their prior abstract nodes. The path between a strict node and its prior node MUST include only network nodes from the strict node and its prior abstract node. The path between a loose node and its prior node MAY include other network nodes, which are not part of the strict node or its prior abstract node. @@ -598,21 +601,21 @@ Parameter values. A Traffic Parameters TLV, is used to signal the Traffic Parameter values. The Traffic Parameters are defined in the subsequent sections. The Traffic Parameters TLV contains a Flags field, a Frequency, a Weight, and the five Traffic Parameters PDR, PBS, CDR, CBS, EBS. The Traffic Parameters TLV is shown below: -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 12 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 12 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|0| Type = 0x0810 | Length = 24 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags | Frequency | Reserved | Weight | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Peak Data Rate (PDR) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Peak Burst Size (PBS) | @@ -652,21 +655,21 @@ Parameter. The Negotiable Flag value zero denotes NotNegotiable and value one denotes Negotiable. Frequency The Frequency field is coded as an 8 bit unsigned integer with the following code points defined: 0- Unspecified 1- Frequent -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 13 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 13 2- VeryFrequent 3-255 - Reserved Reserved - Zero on transmission. Ignored on receipt. Weight An 8 bit unsigned integer indicating the weight of the CR-LSP. Valid weight values are from 1 to 255. The value 0 means that weight is not applicable for the CR-LSP. Traffic Parameters @@ -706,21 +709,21 @@ ingress to the MPLS domain. The Peak Rate is defined in terms of the two Traffic Parameters PDR and PBS, see section 4.3.1.5 below. 4.3.1.3 Committed Rate The Committed Rate defines the rate that the MPLS domain commits to be available to the CR-LSP. -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 14 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 14 The Committed Rate is defined in terms of the two Traffic Parameters CDR and CBS, see section 4.3.1.6 below. 4.3.1.4 Excess Burst Size The Excess Burst Size may be used at the edge of an MPLS domain for the purpose of traffic conditioning. The EBS MAY be used to measure the extent by which the traffic sent on a CR-LSP exceeds the committed rate. @@ -743,36 +746,36 @@ - If Tp(t)-B >= 0, the packet is not in excess of the peak rate and Tp is decremented by B down to the minimum value of 0, else - the packet is in excess of the peak rate and Tp is not decremented. Note that according to the above definition, a positive infinite value of either PDR or PBS implies that arriving packets are never in excess of the peak rate. - The actual implementation of an LSR doesnÆt need to be modeled + The actual implementation of an LSR doesn't need to be modeled according to the above formal token bucket specification. 4.3.1.6 Committed Data Rate Token Bucket The committed rate of a CR-LSP is specified in terms of a token bucket C with rate CDR. The extent by which the offered rate exceeds the committed rate MAY be measured in terms of another token bucket E, which also operates at rate CDR. The maximum size of the token bucket C is CBS and the maximum size of the token bucket E is EBS. The token buckets C and E are initially (at time 0) full, i.e., the token count Tc(0) = CBS and the token count Te(0) = EBS. -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 15 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 15 Thereafter, the token counts Tc and Te are updated CDR times per second as follows: - If Tc is less than CBS, Tc is incremented by one, else - if Te is less then EBS, Te is incremented by one, else neither Tc nor Te is incremented. When a packet of size B bytes arrives at time t, the following happens: @@ -786,98 +789,98 @@ - the packet is in excess of both the Committed Rate and the EBS and neither Tc nor Te is decremented. Note that according to the above specification, a CDR value of positive infinity implies that arriving packets are never in excess of either the Committed Rate or EBS. A positive infinite value of either CBS or EBS implies that the respective limit cannot be exceeded. - The actual implementation of an LSR doesnÆt need to be modeled + The actual implementation of an LSR doesn't need to be modeled according to the above formal specification. 4.3.1.7 Weight - The weight determines the CR-LSPÆs relative share of the possible + The weight determines the CR-LSP's relative share of the possible excess bandwidth above its committed rate. The definition of - "relative shareö is MPLS domain specific. + "relative share" is MPLS domain specific. 4.3.2 Procedures 4.3.2.1 Label Request Message If an LSR receives an incorrectly encoded Traffic Parameters TLV in which the value of PDR is less than the value of CDR then it MUST send a Notification Message including the Status code "Traffic - Parameters Unavailableö to the upstream LSR from which it received + Parameters Unavailable" to the upstream LSR from which it received the erroneous message. If a Traffic Parameter is indicated as Negotiable in the Label Request Message by the corresponding Negotiable Flag then an LSR MAY replace the Traffic Parameter value with a smaller value. -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 16 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 16 If the Weight is indicated as Negotiable in the Label Request Message by the corresponding Negotiable Flag then an LSR may replace the Weight value with a lower value (down to 0). If, after possible Traffic Parameter negotiation, an LSR can support the CR-LSP Traffic Parameters then the LSR MUST reserve the corresponding resources for the CR-LSP. If, after possible Traffic Parameter negotiation, an LSR cannot support the CR-LSP Traffic Parameters then the LSR MUST send a - Notification Message that contains the "Resource Unavailableö status + Notification Message that contains the "Resource Unavailable" status code. 4.3.2.2 Label Mapping Message If an LSR receives an incorrectly encoded Traffic Parameters TLV in which the value of PDR is less than the value of CDR then it MUST send a Label Release message containing the Status code "Traffic - Parameters Unavailableö to the LSR from which it received the + Parameters Unavailable" to the LSR from which it received the erroneous message. In addition, the LSP should send a Notification - Message upstream with the status code "Label Request Abortedö. + Message upstream with the status code 'Label Request Aborted'. If the negotiation flag was set in the label request message, the egress LSR MUST include the (possibly negotiated) Traffic Parameters and Weight in the Label Mapping message. The Traffic Parameters and the Weight in a Label Mapping message MUST be forwarded unchanged. An LSR SHOULD adjust the resources that it reserved for a CR-LSP when it receives a Label Mapping Message if the Traffic Parameters differ from those in the corresponding Label Request Message. 4.3.2.3 Notification Message If an LSR receives a Notification Message for a CR-LSP, it SHOULD release any resources that it possibly had reserved for the CR-LSP. In addition, on receiving a Notification Message from a Downstream LSR that is associated with a Label Request from an upstream LSR, the local LSR MUST propagate the Notification message using the - procedures in [1]. + procedures in [1]. Further the F bit MUST be set. 4.4 Preemption TLV The defualt value of the setup and holding priorities should be in the middle of the range (e.g., 4) so that this feature can be turned on gradually in an operational network by increasing or decreasing the priority starting at the middle of the range. Since the Preemption TLV is an optional TLV, LSPs that are setup without an explicitly signaled preemption TLV SHOULD be treated as LSPs with the default setup and holding priorities (e.g., 4). -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 17 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 17 When an established LSP is preempted, the LSR that initiates the preemption sends a Withdraw Message upstream and a Release Message downstream. When an LSP in the process of being established (outstanding Label Request without getting a Label Mapping back) is preempted, the LSR that initiates the preemption, sends a Notification Message upstream and an Abort Message downstream. 0 1 2 3 @@ -916,35 +919,35 @@ 4.5 LSPID TLV LSPID is a unique identifier of a CR-LSP within an MPLS network. The LSPID is composed of the ingress LSR Router ID (or any of its own Ipv4 addresses) and a Locally unique CR-LSP ID to that LSR. The LSPID is useful in network management, in CR-LSP repair, and in using an already established CR-LSP as a hop in an ER-TLV. -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 18 - An "action indicator flagö is carried in the LSPID TLV. This "action - indicator flagö indicates explicitly the action that should be taken +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 18 + An "action indicator flag" is carried in the LSPID TLV. This "action + indicator flag" indicates explicitly the action that should be taken if the LSP already exists on the LSR receiving the message. After a CR-LSP is set up, its bandwidth reservation may need to be changed by the network operator, due to the new requirements for the - traffic carried on that CR-LSP. The "action indicator flagö is used + traffic carried on that CR-LSP. The "action indicator flag" is used indicate the need to modify the bandwidth and possibly other parameters of an established CR-LSP without service interruption. This feature has application in dynamic network resources management where traffic of different priorities and service classes is involved. - The procedure for the code point "modifyö is defined in [8]. The + The procedure for the code point "modify" is defined in [8]. The procedures for other flags are FFS. 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|0| Type = 0x0821 | Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved |ActFlg | Local CR-LSP ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ingress LSR Router ID | @@ -968,46 +971,46 @@ Reserved Zero on transmission. Ignored on receipt. Local CR-LSP ID The Local LSP ID is an identifier of the CR-LSP locally unique within the Ingress LSR originating the CR-LSP. Ingress LSR Router ID An LSR may use any of its own IPv4 addresses in this field. -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 19 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 19 4.6 Resource Class (Color) TLV The Resource Class as defined in [3] is used to specify which links are acceptable by this CR-LSP. This information allows for the - networkÆs topology to be pruned. + network's topology to be pruned. 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|0| Type = 0x0822 | Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | RsCls | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type A fourteen-bit field carrying the value of the ResCls-TLV Type = 0x0822. Length Specifies the length of the value field in bytes = 4. RsCls The Resource Class bit mask indicating which of the 32 - "administrative groupsö or "colorsö of links the CR-LSP can + "administrative groups" or "colors" of links the CR-LSP can traverse. 4.7 ER-Hop semantics 4.7.1. ER-Hop 1: The IPv4 prefix The abstract node represented by this ER-Hop is the set of nodes, which have an IP address, which lies within this prefix. Note that a prefix length of 32 indicates a single IPv4 node. @@ -1023,21 +1026,21 @@ Type A fourteen-bit field carrying the value of the ER-Hop 1, IPv4 Address, Type = 0x0801 Length Specifies the length of the value field in bytes = 8. L Bit -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 20 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 20 Set to indicate Loose hop. Cleared to indicate a strict hop. Reserved Zero on transmission. Ignored on receipt. PreLen Prefix Length 1-32 IP Address @@ -1076,21 +1079,21 @@ Zero on transmission. Ignored on receipt. PreLen Prefix Length 1-128 IPv6 address A 128-bit unicast host address. 4.7.3. ER-Hop 3: The autonomous system number -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 21 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 21 The abstract node represented by this ER-Hop is the set of nodes belonging to the autonomous system. 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|0| 0x0803 | Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |L| Reserved | AS Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ @@ -1130,21 +1133,21 @@ as part of its state information. This is due to the fact that the upstream LSR needs only to keep the next ER-Hop and the LSPID and the downstream LSR needs only to keep the LSPID in order for each end to be able to recognize that the same LSP is being identified. If the LSPID Hop is not the last hop in an ER-TLV, the LSR must remove the LSP-ID Hop and forward the remaining ER-TLV in a Label Request message using an LDP session established with the LSR that is the specified CR-LSP's egress. That LSR will continue processing -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 22 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 22 of the CR-LSP Label Request Message. The result is a tunneled, or stacked, CR-LSP. To support labels negotiated for tunneled CR-LSP segments, an LDP session is required [1] between tunnel end points - possibly using the existing CR-LSP. Use of the existence of the CR-LSP in lieu of a session, or other possible session-less approaches, is FFS. 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 @@ -1182,37 +1185,37 @@ 4.8.1. Selection of the next hop A Label Request Message containing an explicit route TLV must determine the next hop for this path. Selection of this next hop may involve a selection from a set of possible alternatives. The mechanism for making a selection from this set is implementation dependent and is outside of the scope of this specification. Selection of particular paths is also outside of the scope of this specification, but it is assumed that each node will make a best -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 23 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 23 effort attempt to determine a loop-free path. Note that such best efforts may be overridden by local policy. To determine the next hop for the path, a node performs the following steps: 1. The node receiving the Label Request Message must first evaluate the first ER-Hop. If the L bit is not set in the first ER-Hop and if the node is not part of the abstract node described by the first ER-Hop, it has received the message in error, and - should return a "Bad Initial ER-Hopö error. If the L bit is set + should return a "Bad Initial ER-Hop" error. If the L bit is set and the local node is not part of the abstract node described by the first ER-Hop, the node selects a next hop that is along the path to the abstract node described by the first ER-Hop. If there is no first ER-Hop, the message is also in error and the system - should return a "Bad Explicit Routing TLVö error using a + should return a "Bad Explicit Routing TLV" error using a Notification Message sent upstream. 2. If there is no second ER-Hop, this indicates the end of the explicit route. The explicit route TLV should be removed from the Label Request Message. This node may or may not be the end of the LSP. Processing continues with section 4.8.2, where a new explicit route TLV may be added to the Label Request Message. 3. If the node is also a part of the abstract node described by the second ER-Hop, then the node deletes the first ER-Hop and @@ -1224,33 +1227,33 @@ selects a particular next hop which is a member of the abstract node. The node then deletes the first ER-Hop and continues processing with section 4.8.2. 5. Next, the node selects a next hop within the abstract node of the first ER-Hop that is along the path to the abstract node of the second ER-Hop. If no such path exists then there are two cases: 5.a If the second ER-Hop is a strict ER-Hop, then there is - an error and the node should return a "Bad Strict Nodeö + an error and the node should return a "Bad Strict Node" error. 5.b Otherwise, if the second ER-Hop is a loose ER-Hop, then the node selects any next hop that is along the path to the next abstract node. If no path exists within the MPLS domain, then there is an error, and the node should return a - "Bad loose nodeö error. + "Bad loose node" error. 6. Finally, the node replaces the first ER-Hop with any ER-Hop that denotes an abstract node containing the next hop. This is -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 24 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 24 necessary so that when the explicit route is received by the next hop, it will be accepted. 7. Progress the Label Request Message to the next hop. 4.8.2. Adding ER-Hops to the explicit route TLV After selecting a next hop, the node may alter the explicit route in the following ways. @@ -1289,21 +1292,21 @@ P Bit The P bit is set to 1 to indicate that route pinning is requested. The P bit is set to 0 to indicate that route pinning is not requested Reserved Zero on transmission. Ignored on receipt. -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 25 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 25 4.10 CR-LSP FEC Element A new FEC element is introduced in this specification to support CR- LSPs. A FEC TLV containing a FEC of Element type CR-LSP (0x04) is a CR-LSP FEC TLV. The CR-LSP FEC Element is an opaque FEC to be used only in Messages of CR-LSPs. A single FEC element MUST be included in the Label Request Message. The FEC Element SHOULD be the CR-LSP FEC Element. However, one of @@ -1344,21 +1347,21 @@ - TLV types. - FEC types. - Status codes. The following sections provide guidelines for managing these name spaces. 5.1 TLV Type Name Space -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 26 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 26 RFC 3036 [1] defines the LDP TLV name space. This document further subdivides the range of RFC 3036 from that TLV space for TLVs associated with the CR-LDP in the range 0x0800 - 0x08FF. Following the policies outlined in [IANA], TLV types in this range are allocated through an IETF Consensus action. Initial values for this range are specified in the following table: TLV Type @@ -1369,57 +1372,54 @@ Autonomous System Number ER-Hop TLV 0x0803 LSP-ID ER-Hop TLV 0x0804 Traffic Parameters TLV 0x0810 Preemption TLV 0x0820 LSPID TLV 0x0821 Resource Class TLV 0x0822 Route Pinning TLV 0x0823 5.2 FEC Type Name Space - RFC 3036 defines the FEC Type TLV name space. This document further - subdivides the range of RFC 3036 from that TLV space for TLVs - associated with the CR-LDP in the range 100 - 116. - - Following the policies outlined in [IANA], TLV types in this range - are allocated through an IETF Consensus action. - - Initial values for this range are specified in the follwing table: + RFC 3036 defines the FEC Type name space. Further, RFC 3036 has + assigned values 0x00 through 0x03. FEC types 0 through 127 are + available for assignment through IETF consensus action. This + specification makes the following additional assignment, using + the policies outlined in [IANA]: - FEC Element TLV Type + FEC Element Type -------------------------------------- ---------- - CR-LSP FEC Element TLV 0x0100 + CR-LSP FEC Element 0x04 5.3 Status Code Space RFC 3036 defines the Status Code name space. This document further subdivides the range of RFC 3036 from that TLV space for TLVs - associated with the CR-LDP in the range 0x44000000 - 0x440000FF. + associated with the CR-LDP in the range 0x04000000 - 0x040000FF. Following the policies outlined in [IANA], TLV types in this range are allocated through an IETF Consensus action. - Initial values for this range are specified in the follwing table: + Initial values for this range are specified in the following table: Status Code Type -------------------------------------- ---------- - Bad Explicit Routing TLV Error 0x44000001 -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 27 - Bad Strict Node Error 0x44000002 - Bad Loose Node Error 0x44000003 - Bad Initial ER-Hop Error 0x44000004 - Resource Unavailable 0x44000005 - Traffic Parameters Unavailable 0x44000006 - LSP Preempted 0x44000007 - Modify Request Not Supported 0x44000008 - Setup Abort (Label Request Aborted in [1]) 0x04000015 + Bad Explicit Routing TLV Error 0x04000001 + +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 27 + Bad Strict Node Error 0x04000002 + Bad Loose Node Error 0x04000003 + Bad Initial ER-Hop Error 0x04000004 + Resource Unavailable 0x04000005 + Traffic Parameters Unavailable 0x04000006 + LSP Preempted 0x04000007 + Modify Request Not Supported 0x04000008 6. Security CR-LDP inherits the same security mechanism described in Section 4.0 of [1] to protect against the introduction of spoofed TCP segments into LDP session connection streams. 7. Acknowledgments The messages used to signal the CR-LSP setup are based on the work @@ -1443,43 +1443,42 @@ 2 Rosen et. al., "Multiprotocol Label Switching Architecture", RFC 3031, January 2001. 3 Awduche et. al., "Requirements for Traffic Engineering Over MPLS", RFC 2702, September 1999. 4 Gleeson, et. al., "A Framework for IP Based Virtual Private Networks", RFC 2764, February 2000. - 5 B. Jamoussi, et. al., ôApplicability Statement for CR-LDPö, work + 5 B. Jamoussi, et. al., "Applicability Statement for CR-LDP", work in progress, (draft-ietf-mpls-crldp-applic-01), June 2000. 6 S. Bradner, "Key words for use in RFCs to Indicate Requirement - Levelsö, RFC 2119, March 1997. + Levels", RFC 2119, March 1997. -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 28 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 28 7 L. Wu, et. al., "LDP State Machine", work in progress, (draft-ietf-mpls-ldp-state-03), January 2000. 8 J. Ash, et. al., "LSP Modification Using CR-LDP", work in progress, (draft-ietf-mpls-crlsp-modify-02), October 2000. -10. AuthorÆs Addresses +10. Author's Addresses Osama S. Aboul-Magd Loa Andersson - Nortel Networks Nortel Networks - P O Box 3511 Station C S:t Eriksgatan 115 - Ottawa, ON K1Y 4H7 PO Box 6701 - Canada 113 85 Stockholm - Phone: +1 613 763-5827 Tel: +46 8 508 835 00 - Osama@nortelnetworks.com Fax: +46 8 508 835 01 - Loa_andersson@nortelnetworks.com + Nortel Networks Utfors Bredband AB + P O Box 3511 Station C Rasundavagen 12 169 29 + Ottawa, ON K1Y 4H7 Solna + Canada + Phone: +1 613 763-5827 Tel: +46 8 5270 50 38 + Osama@nortelnetworks.com loa.andersson@utfors.se Peter Ashwood-Smith Ross Callon Nortel Networks Juniper Networks P O Box 3511 Station C 1194 North Mathilda Avenue, Ottawa, ON K1Y 4H7 Sunnyvale, CA 94089 Canada 978-692-6724 Phone: +1 613 763-4534 rcallon@juniper.net Petera@nortelnetworks.com Ram Dantu Paul Doolan @@ -1502,21 +1501,21 @@ Phone: (978) 689-1610 Sterling, VA 20164 eric.gray@sandburst.com 703-433-0808 x207 joel@longsys.com Juha Heinanen Fiffi Hellstrand Telia Finland, Inc. Nortel Networks Myyrmaentie 2 S:t Eriksgatan 115 01600 VANTAA PO Box 6701, 113 85 Stockholm Finland Sweden -Jamoussi, et. al. draft-ietf-mpls-crldp-05.txt 29 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 29 Tel: +358 41 500 4808 +46705593687 Jh@telia.fi fiffi@nortelnetworks.com Bilel Jamoussi Timothy E. Kilty Nortel Networks Corp. Newbridge Networks, Inc. 600 Technology Park Drive 5 Corporate Drive Billerica, MA 01821 Andover, MA 01810 USA USA Phone: +1 978 288-4506 phone: 978 691-4656 Jamoussi@nortelnetworks.com tkilty@northchurch.net @@ -1538,21 +1537,21 @@ Fax: +46 8 508 835 01 Ksundell@nortelnetworks.com Tom Worster Liwen Wu Ennovate Networks Cisco Systems 60 Codman Hill Rd 250 Apollo Drive Boxborough Chelmsford, MA. 01824 MA 01719 Tel: 978-244-3087. tworster@ennovatenetworks.com liwwu@cisco.com -Jamoussi, et. al. draft-ietf-mpls-cr-ldp-04.txt 30 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 30 Appendix A: CR-LSP Establishment Examples A.1 Strict Explicit Route Example This appendix provides an example for the setup of a strictly routed CR-LSP. In this example, a specific node represents each abstract node. The sample network used here is a four node network with two edge @@ -1593,21 +1592,21 @@ Also, LSR2 is not a member of the abstract node described by the first ER-Hop . Finally, the first ER-Hop is a strict hop. Therefore, processing section 4.8.2 does not result in the insertion of new ER-Hops. The selection of the next hop has been already done is step 4 of Section 4.8.1 and the processing of the ER-TLV is -Jamoussi, et. al. draft-ietf-mpls-cr-ldp-04.txt 31 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 31 completed at LSR2. In this case, the Label Request Message including the ER-TLV is progressed by LSR2 to LSR3. At LSR3, a similar processing to the ER-TLV takes place except that the incoming ER-TLV = and the outgoing ER-TLV is . At LSR4, the following processing of section 4.8.1 takes place: 1. The node LSR4 is part of the abstract node described by the first hop . Therefore, the first step passes the test. Go to @@ -1647,21 +1646,21 @@ specific. The ingress LSR uses information provided by the management system or the application and possibly also information from the routing database to calculate the explicit route and to create the Label Request Message. The Label request message carries together with other necessary information an ER-TLV defining the explicitly routed path. In our -Jamoussi, et. al. draft-ietf-mpls-cr-ldp-04.txt 32 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 32 example the list of hops in the ER-Hop TLV is supposed to contain an abstract node representing a group of nodes, an abstract node representing a specific node, another abstract node representing a group of nodes, and an abstract node representing a specific egress point. In--{Group 1}--{Specific A}--{Group 2}--{Specific Out: B} The ER-TLV contains four ER-Hop TLVs: 1. An ER-Hop TLV that specifies a group of LSR valid for the @@ -1699,35 +1698,35 @@ 5. It removes the first ER-Hop TLVs and sends a Label Request Message to the specific node (A). 6. The specific node (A) recognizes itself in the first ER-Hop TLV. Removes the specific ER-Hop TLV. 7. It sends a Label Request Message to a node that is a member of the group (Group 2) indicated in the ER-Hop TLV. -Jamoussi, et. al. draft-ietf-mpls-cr-ldp-04.txt 33 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 33 8. The node that receives the message identifies itself as part of the group indicated in the first ER-Hop TLV, further it realizes that the specific egress node (B) is one of its next hops. 9. It sends a Label Request Message to the specific egress node (B). 10. The specific egress node (B) recognizes itself as the egress for the CR-LSP, it returns a Label Mapping Message, that will traverse the same path as the Label Request Message in the opposite direction. -Jamoussi, et. al. draft-ietf-mpls-cr-ldp-04.txt 34 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 34 Appendix B. QoS Service Examples B.1 Service Examples Construction of an end-to-end service is the result of the rules enforced at the edge and the treatment that packets receive at the network nodes. The rules define the traffic conditioning actions that are implemented at the edge and they include policing with pass, mark, and drop capabilities. The edge rules are expected tobe defined by the mutual agreements between the service providers and @@ -1767,21 +1766,21 @@ ATM-VBR.3(nrt) PCR CDVT SCR MBS 0 Unspecified drop>PCR mark>SCR,MBS ATM-UBR PCR CDVT - - 0 Unspecified drop>PCR ATM-GFR.1 PCR CDVT MCR MBS 0 Unspecified drop>PCR ATM-GFR.2 PCR CDVT MCR MBS 0 Unspecified drop>PCR mark>MCR,MFS -Jamoussi, et. al. draft-ietf-mpls-cr-ldp-04.txt 35 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 35 int-serv-CL p m r b 0 Frequent drop>p drop>r,b S= User specified In the above table, the DS refers to a delay sensitive service where the network commits to deliver with high probability user datagrams at a rate of PDR with minimum delay and delay requirements. Datagrams in excess of PDR will be discarded. @@ -1818,21 +1817,21 @@ the edge. The specification of those actions is expected to be a part of the service level agreement (SLA) negotiation and is not included in the signaling protocol. For DS service, the edge action is to drop packets that exceed the PDR and the PBS specifications. The signaling message will be sent in the direction of the ER path and the LSP is established following the normal LDP procedures. Each LSR applies its admission control rules. If sufficient resources are not available and the parameter values are subject to negotiation, then the LSR could negotiate down the PDR, the PBS, or both. -Jamoussi, et. al. draft-ietf-mpls-cr-ldp-04.txt 36 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 36 The new parameter values are echoed back in the Label Mapping Message. LSRs might need to re-adjust their resource reservations based on the new traffic parameter values. B.3 Establishing CR-LSP Supporting Delay Insensitive Applications In this example we assume that a throughput sensitive (TS) service is requested. For resource allocation the user assigns values for PDR, PBS, CDR, and CBS. The negotiation flag is set if the traffic parameters are subject to negotiation. @@ -1848,32 +1847,32 @@ high discard precedence values for all packets that exceed CDR and the CBS. The edge rules will also include dropping of packets that conform to neither PDR nor PBS. Each LSR of the LSP is expected to run its admission control rules and negotiate traffic parameters down if sufficient resources do not exist. The new parameter values are echoed back in the Label Mapping Message. LSRs might need to re-adjust their resources based on the new traffic parameter values. -Jamoussi, et. al. draft-ietf-mpls-cr-ldp-04.txt 37 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 37 Full Copyright Statement - "Copyright ¨ The Internet Society (date). All Rights Reserved. This + "Copyright À The Internet Society (date). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. -Jamoussi, et. al. draft-ietf-mpls-cr-ldp-04.txt 38 +Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 38