draft-ietf-pce-brpc-07.txt   draft-ietf-pce-brpc-08.txt 
Networking Working Group JP. Vasseur, Ed. Networking Working Group JP. Vasseur, Ed.
Internet-Draft Cisco Systems, Inc Internet-Draft Cisco Systems, Inc
Intended status: Standards Track R. Zhang Intended status: Standards Track R. Zhang
Expires: August 11, 2008 BT Infonet Expires: October 2, 2008 BT Infonet
N. Bitar N. Bitar
Verizon Verizon
JL. Le Roux JL. Le Roux
France Telecom France Telecom
February 8, 2008 March 31, 2008
A Backward Recursive PCE-based Computation (BRPC) procedure to compute A Backward Recursive PCE-based Computation (BRPC) Procedure To Compute
shortest inter-domain Traffic Engineering Label Switched Paths Shortest Constrained Inter-domain Traffic Engineering Label Switched
draft-ietf-pce-brpc-07.txt Paths
draft-ietf-pce-brpc-08.txt
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Copyright (C) The IETF Trust (2008).
Abstract Abstract
The ability to compute shortest constrained Traffic Engineering Label The ability to compute shortest constrained Traffic Engineering Label
Switched Paths (TE LSPs) in Multiprotocol Label Switching (MPLS) and Switched Paths (TE LSPs) in Multiprotocol Label Switching (MPLS) and
Generalized MPLS (GMPLS) networks across multiple domains (where a Generalized MPLS (GMPLS) networks across multiple domains (where a
domain is referred to as a collection of network elements within a domain is a collection of network elements within a common sphere of
common sphere of address management or path computational address management or path computational responsibility such as an
responsibility such as IGP areas and Autonomous Systems) has been IGP area or an Autonomous Systems) has been identified as a key
identified as a key requirement. This document specifies a procedure requirement. This document specifies a procedure relying on the use
relying on the use of multiple Path Computation Elements (PCEs) in of multiple Path Computation Elements (PCEs) to compute such inter-
order to compute such inter-domain shortest constrained paths along a domain shortest constrained paths across a predetermined sequence of
determined sequence of domains, using a backward recursive path domains, using a backward recursive path computation technique. This
computation technique while preserving confidentiality across technique preserves confidentiality across domains, which is
domains, which is sometimes required when domains are managed by sometimes required when domains are managed by different Service
different Service Providers. Providers.
Requirements Language Requirements Language
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 RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
Table of Contents Table of Contents
1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. General assumptions . . . . . . . . . . . . . . . . . . . . . 5 3. General Assumptions . . . . . . . . . . . . . . . . . . . . . 5
4. BRPC Procedure . . . . . . . . . . . . . . . . . . . . . . . . 6 4. BRPC Procedure . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Domain path selection . . . . . . . . . . . . . . . . . . 6 4.1. Domain Path Selection . . . . . . . . . . . . . . . . . . 7
4.2. Mode of Operation . . . . . . . . . . . . . . . . . . . . 7 4.2. Mode of Operation . . . . . . . . . . . . . . . . . . . . 7
5. PCEP Protocol Extensions . . . . . . . . . . . . . . . . . . . 9 5. PCEP Protocol Extensions . . . . . . . . . . . . . . . . . . . 9
6. VSPT Encoding . . . . . . . . . . . . . . . . . . . . . . . . 9 6. VSPT Encoding . . . . . . . . . . . . . . . . . . . . . . . . 9
7. Inter-AS TE Links . . . . . . . . . . . . . . . . . . . . . . 10 7. Inter-AS TE Links . . . . . . . . . . . . . . . . . . . . . . 10
8. Usage in conjunction with per-domain path computation . . . . 10 8. Usage In Conjunction With Per-domain Path Computation . . . . 11
9. BRPC procedure completion failure . . . . . . . . . . . . . . 10 9. BRPC Procedure Completion Failure . . . . . . . . . . . . . . 11
10. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 11 10. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 11
10.1. Diverse end-to-end path computation . . . . . . . . . . . 11 10.1. Diverse end-to-end path computation . . . . . . . . . . . 12
10.2. Path optimality . . . . . . . . . . . . . . . . . . . . . 12 10.2. Path Optimality . . . . . . . . . . . . . . . . . . . . . 12
11. Reoptimization of an inter-domain TE LSP . . . . . . . . . . . 12 11. Reoptimization Of An Inter-domain TE LSP . . . . . . . . . . . 12
12. Path Computation failure . . . . . . . . . . . . . . . . . . . 12 12. Path Computation Failure . . . . . . . . . . . . . . . . . . . 13
13. Metric normalization . . . . . . . . . . . . . . . . . . . . . 12 13. Metric Normalization . . . . . . . . . . . . . . . . . . . . . 13
14. Manageability Considerations . . . . . . . . . . . . . . . . . 13 14. Manageability Considerations . . . . . . . . . . . . . . . . . 13
14.1. Control of Function and Policy . . . . . . . . . . . . . . 13 14.1. Control of Function And Policy . . . . . . . . . . . . . . 13
14.2. Information and Data Models . . . . . . . . . . . . . . . 13 14.2. Information And Data Models . . . . . . . . . . . . . . . 14
14.3. Liveness Detection and Monitoring . . . . . . . . . . . . 13 14.3. Liveness Detection and Monitoring . . . . . . . . . . . . 14
14.4. Verifying Correct Operation . . . . . . . . . . . . . . . 13 14.4. Verifying Correct Operation . . . . . . . . . . . . . . . 14
14.5. Requirements on Other Protocols and Functional 14.5. Requirements on Other Protocols and Functional
Components . . . . . . . . . . . . . . . . . . . . . . . . 14 Components . . . . . . . . . . . . . . . . . . . . . . . . 14
14.6. Impact on Network Operation . . . . . . . . . . . . . . . 14 14.6. Impact on Network Operation . . . . . . . . . . . . . . . 14
14.7. Path computation chain monitoring . . . . . . . . . . . . 14 14.7. Path Computation Chain Monitoring . . . . . . . . . . . . 15
15. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 15. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
15.1. New flag of the RP object . . . . . . . . . . . . . . . . 14 15.1. New Flag Of The RP Object . . . . . . . . . . . . . . . . 15
15.2. new Error-Type and Error-Value . . . . . . . . . . . . . . 14 15.2. New Error-Type And Error-Value . . . . . . . . . . . . . . 15
15.3. New flag of the NO-PATH-VECTOR TLV . . . . . . . . . . . . 15 15.3. New Flag Of The NO-PATH-VECTOR TLV . . . . . . . . . . . . 15
16. Security Considerations . . . . . . . . . . . . . . . . . . . 15 16. Security Considerations . . . . . . . . . . . . . . . . . . . 16
17. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 15 17. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 16
18. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15 18. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16
18.1. Normative References . . . . . . . . . . . . . . . . . . . 15 18.1. Normative References . . . . . . . . . . . . . . . . . . . 16
18.2. Informative References . . . . . . . . . . . . . . . . . . 16 18.2. Informative References . . . . . . . . . . . . . . . . . . 16
Appendix A. Proposed Status and Discussion [To Be Removed Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18
Upon Publication] . . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17
Intellectual Property and Copyright Statements . . . . . . . . . . 19 Intellectual Property and Copyright Statements . . . . . . . . . . 19
1. Terminology 1. Introduction
ABR: routers used to connect two IGP areas (areas in OSPF or levels The requirements for inter-area and inter-AS MPLS Traffic Engineering
in IS-IS). (TE) have been developed by the Traffic Engineering Working Group (TE
WG) and have been stated in [RFC4105] and [RFC4216], respectively.
ASBR: routers used to connect together ASes of the same or different The framework for inter-domain Multiprotocol Label Switching (MPLS)
Service Provider(s) via one or more Inter-AS links. Traffic Engineering (TE) has been provided in [RFC4726].
[RFC5152] defines a technique for establishing an inter-domain
Generalized MPLS (GMPLS) TE Label Switched Path (LSP) whereby the
path is computed during the signalling process on a per-domain basis
by the entry boundary node of each domain (each node responsible for
triggering the computation of a section of an inter-domain TE LSP
path is always along the path of such TE LSP). This path computation
technique fulfills some of the requirements stated in [RFC4105] and
[RFC4216] but not all of them. In particular, it cannot guarantee to
find an optimal (shortest) inter-domain constrained path.
Furthermore, it cannot be efficiently used to compute a set of inter-
domain diversely routed TE LSPs.
The Path Computation Element (PCE) architecture is defined in
[RFC4655]. The aim of this document is to describe a PCE-based path
computation procedure to compute optimal inter-domain constrained
(G)MPLS TE LSPs.
Qualifying a path as optimal requires some clarification. Indeed, a
globally optimal TE LSP placement usually refers to a set of TE LSPs
whose placements optimize the network resources with regards to a
specified objective function (e.g., a placement that reduces the
maximum or average network load while satisfying the TE LSP
constraints). In this document, an optimal inter-domain constrained
TE LSP is defined as the shortest path satisfying the set of required
constraints that would be obtained in the absence of multiple domains
(in other words, in a totally flat IGP network between the source and
destination of the TE LSP). Note that this requires to use
consistent metric schemes in each domain (see section Section 13).
2. Terminology
ABR: Area Border Routers. Routers used to connect two IGP areas
(areas in OSPF or levels in IS-IS).
ASBR: Autonomous System Border Routers. Routers used to connect
together ASes of the same or different Service Providers via one or
more Inter-AS links.
Boundary Node (BN): a boundary node is either an ABR in the context Boundary Node (BN): a boundary node is either an ABR in the context
of inter-area Traffic Engineering or an ASBR in the context of of inter-area Traffic Engineering or an ASBR in the context of
inter-AS Traffic Engineering. inter-AS Traffic Engineering.
Entry BN of domain(n): a BN connecting domain(n-1) to domain(n) along Entry BN of domain(n): a BN connecting domain(n-1) to domain(n) along
a determined sequence of domains. a determined sequence of domains.
Exit BN of domain(n): a BN connecting domain(n) to domain(n+1) along Exit BN of domain(n): a BN connecting domain(n) to domain(n+1) along
a determined sequence of domains. a determined sequence of domains.
skipping to change at page 4, line 47 skipping to change at page 5, line 39
PCE(i) is a PCE with the scope of domain(i). PCE(i) is a PCE with the scope of domain(i).
TED: Traffic Engineering Database. TED: Traffic Engineering Database.
VSPT: Virtual Shortest Path Tree. VSPT: Virtual Shortest Path Tree.
The notion of contiguous, stitched and nested TE LSPs is defined in The notion of contiguous, stitched and nested TE LSPs is defined in
[RFC4726] and will not be repeated here. [RFC4726] and will not be repeated here.
2. Introduction 3. General Assumptions
The requirements for inter-area and inter-AS MPLS Traffic Engineering
have been developed by the Traffic Engineering Working Group (TE WG)
and have been stated in [RFC4105] and [RFC4216], respectively.
The framework for inter-domain MPLS Traffic Engineering has been
provided in [RFC4726].
[I-D.ietf-ccamp-inter-domain-pd-path-comp] defines a technique for
establishing inter-domain (G)MPLS TE LSP whereby the path is computed
during the signalling process on a per-domain basis by the entry
boundary node of each domain (each node in charge of computing a
section of an inter-domain TE LSP path is always along the path of
such TE LSP). Such path computation technique fulfills some of the
requirements stated in [RFC4105] and [RFC4216] but not all of them.
In particular, it cannot guarantee to find an optimal (shortest)
inter-domain constrained path. Furthermore, it cannot be efficiently
used to compute a set of inter-domain diversely routed TE LSPs.
The PCE architecture is defined in [RFC4655]. The aim of this
document is to describe a PCE-based path computation procedure to
compute optimal inter-domain constrained (G)MPLS TE LSPs.
Qualifying a path as optimal requires some clarification. Indeed, a
globally optimal TE LSP placement usually refers to a set of TE LSPs
whose placements optimize the network resources with regards to a
specified objective function (e.g., a placement that reduces the
maximum or average network load while satisfying the TE LSP
constraints). In this document, an optimal inter-domain constrained
TE LSP is defined as the shortest path satisfying the set of required
constraints that would be obtained in the absence of multiple domains
(in other words, in a totally flat IGP network between the source and
destination of the TE LSP).
3. General assumptions
In the rest of this document, we make the following set of In the rest of this document, we make the following set of
assumptions common to inter-area and inter-AS MPLS TE: assumptions common to inter-area and inter-AS MPLS TE:
- Each IGP area or Autonomous System (AS) is assumed to be Traffic o Each IGP area or Autonomous System (AS) is assumed to be Traffic
Engineering enabled (i.e. running OSPF-TE or ISIS-TE and RSVP-TE). Engineering enabled.
- No topology or resource information is distributed between domains o No topology or resource information is distributed between domains
(as mandated per [RFC4105] and [RFC4216]), which is critical to (as mandated per [RFC4105] and [RFC4216]), which is critical to
preserve IGP/BGP scalability and confidentiality. preserve IGP/BGP scalability and confidentiality.
- While certain constraints like bandwidth can be used across o While certain constraints like bandwidth can be used across
different domains, other TE constraints like resource affinity, different domains, other TE constraints like resource affinity,
color, metric, etc. as listed in [RFC2702] could be translated at color, metric, etc. as listed in [RFC2702] could be translated at
domain boundaries. If required, it is assumed that, at the domain domain boundaries. If required, it is assumed that, at the domain
boundary nodes, there will exist some sort of local mapping based on boundary nodes, there will exist some sort of local mapping based
policy agreement, in order to translate such constraints across on policy agreement, in order to translate such constraints across
domain boundaries during the inter-PCE communication process. domain boundaries during the inter-PCE communication process.
- Each AS can be made of several IGP areas. The path computation o Each AS can be made of several IGP areas. The path computation
procedure described in this document applies to the case of a single procedure described in this document applies to the case of a
AS made of multiple IGP areas, multiple ASes made of a single IGP single AS made of multiple IGP areas, multiple ASes made of a
area or any combination of the above. For the sake of simplicity, single IGP area or any combination of the above. For the sake of
each AS will be considered to be made of a single area in this simplicity, each AS will be considered to be made of a single area
document. The case of an Inter-AS TE LSP spanning multiple ASes in this document. The case of an Inter-AS TE LSP spanning
where some of those ASes are themselves made of multiple IGP areas multiple ASes where some of those ASes are themselves made of
can be easily derived from this case by applying the BRPC procedure multiple IGP areas can be easily derived from this case by
described in this document, recursively. applying the BRPC procedure described in this document,
recursively.
- The domain path (set of domains traversed to reach the destination o The domain path (set of domains traversed to reach the destination
domain) is either administratively pre-determined or discovered by domain) is either administratively pre-determined or discovered by
some means that are outside of the scope of this document. some means that is outside of the scope of this document.
4. BRPC Procedure 4. BRPC Procedure
The BRPC procedure is a Multiple-PCE path computation technique as The BRPC procedure is a Multiple-PCE path computation technique as
described in [RFC4655]. A possible model consists of hosting the PCE described in [RFC4655]. A possible model consists of hosting the PCE
function on boundary nodes (e.g., ABR or ASBR) but this is not function on boundary nodes (e.g., ABR or ASBR) but this is not
mandated by the BRPC procedure. mandated by the BRPC procedure.
The BRPC procedure relies on communication between cooperating PCEs.
In particular, the PCC sends a PCReq to a PCE in its domain. The
request is forwarded between PCEs, domain-by-domain until the PCE
responsible for the domain containing the LSP destination is reached.
The PCE in the destination domain creates a tree of potential paths
to the destination (the Virtual Shortest Path Tree - VSPT) and passes
this back to the previous PCE in a PCRep. Each PCE in turn adds to
the VSPT and passes it back until the PCE in the source domain uses
the VSPT to select an end-to-end path that it sends to the PCC.
The BRPC procedure does not make any assumption with regards to the The BRPC procedure does not make any assumption with regards to the
nature of the inter-domain TE LSP that could be contiguous, nested or nature of the inter-domain TE LSP that could be contiguous, nested or
stitched. stitched.
Furthermore, no assumption is made on the actual path computation Furthermore, no assumption is made on the actual path computation
algorithm in use by a PCE (e.g., it can be any variant of CSPF or an algorithm in use by a PCE (e.g., it can be any variant of CSPF or an
algorithm based on linear-programming to solve multi-constraints algorithm based on linear-programming to solve multi-constraint
optimization problems). optimization problems).
4.1. Domain path selection 4.1. Domain Path Selection
The PCE-based BRPC procedure applies to the computation of an optimal The PCE-based BRPC procedure applies to the computation of an optimal
constrained inter-domain TE LSP. The sequence of domains to be constrained inter-domain TE LSP. The sequence of domains to be
traversed can either be determined a priori or during the path traversed is either administratively pre-determined or discovered by
computation procedure. The BRPC procedure guarantees to compute the some means that is outside of the scope of this document. The PCC
optimal path across a specific sequence of traversed domains (which MAY indicate the sequence of domains to be traversed using the IRO
constitutes an additional constraint). In the case of an arbitrary defined in [I-D.ietf-pce-pcep] so that it is available to all PCEs.
set of meshed domains, the BRPC procedure can be used to compute the Note also that a sequence of PCEs MAY be enforced by policy on the
optimal path across each domain set in order to get the optimal PCC and this constraint can be carried in the PCEP path computation
constrained path between the source and the destination of the TE request (as defined in [I-D.ietf-pce-monitoring]).
LSP. The BRPC procedure can also be used across a subset of all
domain sequences, and the best path among these sequences can then be The BRPC procedure guarantees to compute the optimal path across a
selected. specific sequence of traversed domains (which constitutes an
additional constraint). In the case of an arbitrary set of meshed
domains, the BRPC procedure can be used to compute the optimal path
across each domain set in order to get the optimal constrained path
between the source and the destination of the TE LSP. The BRPC
procedure can also be used across a subset of all domain sequences,
and the best path among these sequences can then be selected.
4.2. Mode of Operation 4.2. Mode of Operation
Definition of VSPT(i) Definition of VSPT(i)
In each domain i: In each domain i:
* There is a set of X-en(i) entry BNs noted BN-en(k,i) where BN- o There is a set of X-en(i) entry BNs noted BN-en(k,i) where BN-
en(k,i) is the kth entry BN of domain(i). en(k,i) is the kth entry BN of domain(i).
* There is a set of X-ex(i) exit BNs noted BN-ex(k,i) where BN- o There is a set of X-ex(i) exit BNs noted BN-ex(k,i) where BN-
ex(k,i) is the kth exit BN of domain(i). ex(k,i) is the kth exit BN of domain(i).
VSPT(i): MP2P (MultiPoint To Point) tree returned by PCE(i) to VSPT(i): MP2P (MultiPoint To Point) tree returned by PCE(i) to
PCE(i-1): PCE(i-1):
Root (TE LSP destination) Root (TE LSP destination)
/ I \ / I \
BN-en(1,i) BN-en(2,i) ... BN-en((j), i). BN-en(1,i) BN-en(2,i) ... BN-en(j,i).
Where [X-en(i)] is the number of entry BN in domain i Where [X-en(i)] is the number of entry BNs in domain i
and j<= [X-en(i)] and j<= [X-en(i)]
Figure 1 - MP2P Tree Figure 1 - MP2P Tree
Each link of tree VSPT(i) represents the shortest constrained path Each link of tree VSPT(i) represents the shortest constrained path
between BN-en(j,i) (identified by its TE Router-ID) and the TE LSP between BN-en(j,i) and the TE LSP destination that satisfies the set
destination that satisfies the set of required constraints for the TE of required constraints for the TE LSP (bandwidth, affinities, ...).
LSP (bandwidth, affinities, ...). These are path segments to reach These are path segments to reach the TE LSP destination from BN-
the TE LSP destination from BN-en(j,i). en(j,i).
Note that PCE(i) only considers the entry BNs that provide Note that PCE(i) only considers the entry BNs of domain(i). That is
connectivity from domain(i-1). That is, the set BN-en(k,i-1) is only only the BNs that provide connectivity from domain(i-1). That is,
made of those BNs that provide connectivity from domain (i-1) to the set BN-en(k,i) is only made of those BNs that provide
domain(i). Furthermore, some BNs may be excluded according to policy connectivity from domain (i-1) to domain(i). Furthermore, some BNs
constraints (either due to local policy or policies signaled in the may be excluded according to policy constraints (either due to local
path computation request). policy or policies signaled in the path computation request).
Step 1: the PCC needs to first determine the PCE capable of serving Step 1: the PCC needs to first determine the PCE capable of serving
its path computation request (this can be done thanks to local its path computation request (this can be done thanks to local
configuration or via IGP discovery (see [RFC5088] and [RFC5089])). configuration or via IGP discovery (see [RFC5088] and [RFC5089])).
The path computation request is then relayed until reaching a PCE(n) The path computation request is then relayed until reaching a PCE(n)
such that the TE LSP destination resides in the domain(n). At each such that the TE LSP destination resides in the domain(n). At each
step of the process, the next PCE can either be statically configured step of the process, the next PCE can either be statically configured
or dynamically discovered via IGP/BGP extensions. If no next PCE can or dynamically discovered via IGP/BGP extensions. If no next PCE can
be found or the next hop PCE of choice is unavailable, the procedure be found or the next hop PCE of choice is unavailable, the procedure
stops and a path computation error is returned (see Section 9). If stops and a path computation error is returned (see Section 9). If
multiple PCEs are discovered, the PCE may select a subset of these PCE(i-1) discovers multiple PCEs for the adjacent domain(i), PCE(i)
PCEs based on some local policies or heuristics. The PCE selection may select a subset of these PCEs based on some local policies or
process is outside of the scope of this document. Note also that a heuristics. The PCE selection process is outside of the scope of
sequence of PCEs might be enforced by policy on the PCC and this this document.
constraint can be carried in the PCEP path computation request (as
defined in [I-D.ietf-pce-monitoring]).
Step 2: PCE(n) computes VSPT(n) made of the list of shortest Step 2: PCE(n) computes VSPT(n) made of the list of shortest
constrained path(s) between every BN-en(j,n) and the TE LSP constrained paths between every BN-en(j,n) and the TE LSP destination
destination using a suitable path computation algorithm (e.g. CSPF) using a suitable path computation algorithm (e.g. CSPF) and returns
and returns the computed VSPT(n) to PCE(n-1). the computed VSPT(n) to PCE(n-1).
Step i: Step i:
- For i=n-1 to 2: PCE(i) concatenates the topology of domain(i) - For i=n-1 to 2: PCE(i) computes VSPT(i), the tree made of the
(using its TED) with the received VSPT(i+1). shortest constrained paths between each BN-en(j,i) and the TE LSP
destination. It does this by considering its own TED and the
information in VSPT(i+1).
In the case of Inter-AS TE LSP computation, this requires to also add In the case of Inter-AS TE LSP computation, this requires to also add
the inter-AS TE links connecting the domain(i) to the domain(i+1). the inter-AS TE links connecting the domain(i) to the domain(i+1).
Then PCE(i) computes VSPT(i) (MP2P (Multi-Point to Point) tree made Step n
of the shortest constrained paths between each BN-en(j,i) and the TE
LSP destination).
End
Finally PCE(1) computes the end-to-end shortest constrained path from Finally PCE(1) computes the end-to-end shortest constrained path from
the source to the destination and returns the corresponding path to the source to the destination and returns the corresponding path to
the requesting PCC in the form of a PCRep message as defined in the requesting PCC in the form of a PCRep message as defined in
[I-D.ietf-pce-pcep]. [I-D.ietf-pce-pcep].
Each branch of the VSPT tree (path) may be returned in the form of an Each branch of the VSPT tree (path) may be returned in the form of an
explicit path (in which case all the hops along the path segment are explicit path (in which case all the hops along the path segment are
listed) or a loose path (in which case only the BR is specified) so listed) or a loose path (in which case only the BN is specified) so
as to preserve confidentiality along with the respective cost. In as to preserve confidentiality along with the respective cost. In
the later case, various techniques can be used in order to retrieve the later case, various techniques can be used in order to retrieve
the computed explicit paths on a per domain basis during the the computed explicit paths on a per domain basis during the
signaling process thanks to the use of path keys as described in signaling process thanks to the use of path keys as described in
[I-D.ietf-pce-path-key]. [I-D.ietf-pce-path-key].
BRPC guarantees to find the optimal (shortest) constrained inter- BRPC guarantees to find the optimal (shortest) constrained inter-
domain TE LSP according to a set of defined domains to be traversed. domain TE LSP according to a set of defined domains to be traversed.
Note that other variants of the BRPC procedure relying on the same Note that other variants of the BRPC procedure relying on the same
principles are also possible. principles are also possible.
skipping to change at page 9, line 24 skipping to change at page 9, line 41
The following new flag of the RP object is defined: The following new flag of the RP object is defined:
VSPT Flag VSPT Flag
Bit Number Name Flag Bit Number Name Flag
7 VSPT 7 VSPT
When set, the VSPT Flag indicates that the PCC requests the When set, the VSPT Flag indicates that the PCC requests the
computation of an inter-domain TE LSP using the BRPC procedure computation of an inter-domain TE LSP using the BRPC procedure
defined in this document. defined in this document.
Because path segment(s) computed by a downstream PCE in the context Because path segments computed by a downstream PCE in the context of
of the BRPC procedure MUST be provided along with their respective the BRPC procedure MUST be provided along with their respective path
path cost(s), the C flag of the METRIC object carried within the costs, the C flag of the METRIC object carried within the PCReq
PCReq message MUST be set. It is the choice of the requester to message MUST be set. It is the choice of the requester to
appropriately set the O bit of the RP object. appropriately set the O bit of the RP object.
6. VSPT Encoding 6. VSPT Encoding
The VSPT is returned within a PCRep message. The encoding consists The VSPT is returned within a PCRep message. The encoding consists
of a non-ordered lists of EROs where each ERO represents a path of a non-ordered lists of EROs where each ERO represents a path
segment from an ABR to the destination specified in the END-POINT segment from a BN to the destination specified in the END-POINT
object of the corresponding PCReq message. object of the corresponding PCReq message.
Example: Example:
<---- area 1 ----><---- area 0 -----><------ area 2 ------> <---- area 1 ----><---- area 0 -----><------ area 2 ------>
ABR1-A-B-+ ABR1-A-B-+
| | | |
ABR2-----D ABR2-----D
| | | |
ABR3--C--+ ABR3--C--+
skipping to change at page 10, line 13 skipping to change at page 10, line 30
D, the VSPT computed by a PCE serving area 2 consists of the D, the VSPT computed by a PCE serving area 2 consists of the
following non-ordered set of EROs: following non-ordered set of EROs:
o ERO1: ABR1(TE Router ID)-A(Interface IP address)-B(Interface IP o ERO1: ABR1(TE Router ID)-A(Interface IP address)-B(Interface IP
address)-D(TE Router ID) address)-D(TE Router ID)
o ERO2: ABR2(TE Router ID)-D(TE Router ID) o ERO2: ABR2(TE Router ID)-D(TE Router ID)
o ERO3: ABR3(TE Router ID)-C(interface IP adress)-D(TE Router ID) o ERO3: ABR3(TE Router ID)-C(interface IP adress)-D(TE Router ID)
The PCERep message, PCRep message, PCEP END-POINT and ERO objects are The PCReq message, PCRep message, PCEP END-POINT and ERO objects are
defined in [I-D.ietf-pce-pcep] defined in [I-D.ietf-pce-pcep]
7. Inter-AS TE Links 7. Inter-AS TE Links
In the case of Inter-AS TE LSP path computation, the BRPC procedure In the case of Inter-AS TE LSP path computation, the BRPC procedure
requires the knowledge of the traffic engineering attributes of the requires the knowledge of the traffic engineering attributes of the
Inter-AS TE links: the process by which the PCE acquires this Inter-AS TE links: the process by which the PCE acquires this
information is out of the scope of the BRPC procedure, which is information is out of the scope of the BRPC procedure, which is
compliant with the PCE architecture defined in [RFC4655]. compliant with the PCE architecture defined in [RFC4655].
That said, a straightforward solution consists of allowing the ASBRs That said, a straightforward solution consists of allowing the ASBRs
to flood the TE information related to the inter-ASBR link(s) to flood the TE information related to the inter-ASBR links although
although no IGP TE is enabled over those links (there is no IGP no IGP TE is enabled over those links (there is no IGP adjacency over
adjacency over the inter-ASBR links). This allows the PCE of a the inter-ASBR links). This allows the PCE of a domain to get entire
domain to get entire TE visibility up to the set of entry ASBRs in TE visibility up to the set of entry ASBRs in the downstream domain
the downstream domain (see the IGP extensions defined in (see the IGP extensions defined in
[I-D.ietf-ccamp-isis-interas-te-extension] and [I-D.ietf-ccamp-isis-interas-te-extension] and
[I-D.ietf-ccamp-ospf-interas-te-extension]). [I-D.ietf-ccamp-ospf-interas-te-extension]).
8. Usage in conjunction with per-domain path computation 8. Usage In Conjunction With Per-domain Path Computation
The BRPC procedure may be used to compute path segments in The BRPC procedure may be used to compute path segments in
conjunction with other path computation techniques (such as the per- conjunction with other path computation techniques (such as the per-
domain path computation technique defined in domain path computation technique defined in [RFC5152]) to compute
[I-D.ietf-ccamp-inter-domain-pd-path-comp]) to compute the end-to-end the end-to-end path. In this case end-to-end path optimality can no
path. In this case end-to-end path optimality can no longer be longer be guaranteed.
guaranteed.
9. BRPC procedure completion failure 9. BRPC Procedure Completion Failure
If the BRPC procedure cannot be completed because a PCE along the If the BRPC procedure cannot be completed because a PCE along the
domain path does not support the procedure, a PCErr message MUST be domain does not recognize the procedure (VSPT flag of the RP object),
returned to the upstream PCE with a Error-Type "BRPC procedure as stated in [I-D.ietf-pce-pcep], the PCE sends a PCErr message to
completion failure". The PCErr message MUST be relayed to the the upstream PCE with an Error-Type=4 (not supported object), Error-
requesting PCC. value-4 (Unsupported paramater). The PCE may include the parent
object (RP object) up to and including (but no further than) the
unknown or unsupported parameter. In this case where the unknown or
unsupported parameter is a bit flag (VSPT flag), the included RP
object should contain the whole bit flag field with all bits after
the parameter at issue set to zero. The corresponding path
computation request is then cancelled by the PCE without further
notification.
If the BRPC procedure cannot be completed because a PCE along the
domain path recognises but does not support the procedure, it MUST
return a PCErr message to the upstream PCE with an Error-Type "BRPC
procedure completion failure".
The PCErr message MUST be relayed to the requesting PCC.
PCEP-ERROR objects are used to report a PCEP protocol error and are PCEP-ERROR objects are used to report a PCEP protocol error and are
characterized by an Error-Type which specifies the type of error and characterized by an Error-Type which specifies the type of error and
an Error-value that provides additional information about the error an Error-value that provides additional information about the error
type. Both the Error-Type and the Error-Value are managed by IANA. type. Both the Error-Type and the Error-Value are managed by IANA.
A new Error-Type is defined that relates to the BRPC procedure. A new Error-Type is defined that relates to the BRPC procedure.
Error-type Meaning Error-type Meaning
13 BRPC procedure completion failure 13 BRPC procedure completion failure
Error-value Error-value
skipping to change at page 11, line 32 skipping to change at page 12, line 15
and [RFC4216], respectively. Among the set of requirements, both and [RFC4216], respectively. Among the set of requirements, both
documents indicate the need for some solution providing the ability documents indicate the need for some solution providing the ability
to compute an optimal (shortest) constrained inter-domain TE LSP and to compute an optimal (shortest) constrained inter-domain TE LSP and
to compute a set of diverse inter-domain TE LSPs. to compute a set of diverse inter-domain TE LSPs.
10.1. Diverse end-to-end path computation 10.1. Diverse end-to-end path computation
PCEP (see [I-D.ietf-pce-pcep]) allows a PCC to request the PCEP (see [I-D.ietf-pce-pcep]) allows a PCC to request the
computation of a set of diverse TE LSPs thanks to the SVEC object by computation of a set of diverse TE LSPs thanks to the SVEC object by
setting the flags L, N or S to request link, node or SRLG diversity setting the flags L, N or S to request link, node or SRLG diversity
respectively. Such request MUST be taken into account by each PCE respectively. Such requests MUST be taken into account by each PCE
along the path computation chain during the VSPT computation. In the along the path computation chain during the VSPT computation. In the
context of the BRPC procedure, a set of diversely routed TE LSP context of the BRPC procedure, a set of diversely routed TE LSPs
between two LSRs can be computed since the paths segment(s) of the between two LSRs can be computed since the paths segments of the VSPT
VSPT are simultaneously computed by a given PCE. The BRPC procedure are simultaneously computed by a given PCE. The BRPC procedure
allows for the computation of diverse paths under various objective allows for the computation of diverse paths under various objective
functions (such as minimizing the sum of the costs of the N diverse functions (such as minimizing the sum of the costs of the N diverse
paths, etc). paths, etc).
By constrast, with a 2-step approach consisting of computing the By constrast, with a 2-step approach consisting of computing the
first path followed by the computation of the second path after first path followed by the computation of the second path after
having removed the set of network elements traversed by the first having removed the set of network elements traversed by the first
path (if that does not violate confidentiality preservation), one path (if that does not violate confidentiality preservation), one
cannot guarantee that a solution will be found even if such solution cannot guarantee that a solution will be found even if such solution
exists. Furthermore, even if a solution is found, it may not be the exists. Furthermore, even if a solution is found, it may not be the
most optimal one with respect to an objective function such as most optimal one with respect to an objective function such as
minimizing the sum of the paths costs, bounding the path delays of minimizing the sum of the paths costs, bounding the path delays of
both paths and so on. Finally, it must be noted that such a 2-step both paths and so on. Finally, it must be noted that such a 2-step
path computation approach is usually less efficient in term of path computation approach is usually less efficient in term of
signalling delays since it requires two serialized TE LSP set up. signalling delays since it requires two serialized TE LSP set up.
10.2. Path optimality 10.2. Path Optimality
BRPC guarantees that the optimal (shortest) constrained inter-domain BRPC guarantees that the optimal (shortest) constrained inter-domain
path will always be found subject to policy constraints. When path will always be found subject to policy constraints. When
combined with other local path computation techniques (e.g. in the combined with other local path computation techniques (e.g. in the
case of stitched/nested TE LSP) and in the case where a domain has case of stitched/nested TE LSP) and in the case where a domain has
more than one BR-en or more than one BR-ex, optimality after some more than one BN-en or more than one BN-ex, optimality after some
network change within the domain can only be guaranteed by re- network change within the domain can only be guaranteed by re-
executing the BRPC procedure. executing the BRPC procedure.
11. Reoptimization of an inter-domain TE LSP 11. Reoptimization Of An Inter-domain TE LSP
The ability to reoptimize an existing inter-domain TE LSP path has The ability to reoptimize an existing inter-domain TE LSP path has
been explicitly listed as a requirement in [RFC4105] and [RFC4216]. been explicitly listed as a requirement in [RFC4105] and [RFC4216].
In the case of a TE LSP reoptimization request, the reoptimization In the case of a TE LSP reoptimization request, the reoptimization
procedure defined in [I-D.ietf-pce-pcep] applies where the path in procedure defined in [I-D.ietf-pce-pcep] applies where the path in
use (if available on the head-end) is provided as part of the path use (if available on the head-end) is provided as part of the path
computation request in order for the PCEs involved in the computation request in order for the PCEs involved in the
reoptimization request to avoid double bandwidth accounting. reoptimization request to avoid double bandwidth accounting.
12. Path Computation failure 12. Path Computation Failure
If a PCE requires to relay a path computation request according to If a PCE requires to relay a path computation request according to
the BRPC procedure defined in this document to a downstream PCE and the BRPC procedure defined in this document to a downstream PCE and
no such PCE is available, the PCE MUST send a negative path no such PCE is available, the PCE MUST send a negative path
computation reply to the requester using a PCReq message as specified computation reply to the requester using a PCReq message as specified
in [I-D.ietf-pce-pcep] that contains a NO-PATH object. In such case, in [I-D.ietf-pce-pcep] that contains a NO-PATH object. In such case,
the NO-PATH object MUST carry a NO-PATH-VECTOR TLV (defined in the NO-PATH object MUST carry a NO-PATH-VECTOR TLV (defined in
[I-D.ietf-pce-pcep]) with the newly defined bit named "BRPC Path [I-D.ietf-pce-pcep]) with the newly defined bit named "BRPC Path
Computation chain unavailable" set. Computation chain unavailable" set.
Bit number Name Flag Bit number Name Flag
4 BRPC Path computation chain unavailable 4 BRPC Path computation chain unavailable
13. Metric normalization 13. Metric Normalization
In the case of inter-area TE, the same IGP/TE metric scheme is In the case of inter-area TE, the same IGP/TE metric scheme is
usually adopted for all the IGP areas (e.g., based on the link-speed, usually adopted for all the IGP areas (e.g., based on the link-speed,
propagation delay or some other combination of link attributes). propagation delay or some other combination of link attributes).
Hence, the proposed set of mechanisms always computes the shortest Hence, the proposed set of mechanisms always computes the shortest
path across multiple areas obeying the required set of constraints path across multiple areas obeying the required set of constraints
with respect to a specified objective function. Conversely, in the with respect to a specified objective function. Conversely, in the
case of Inter-AS TE, in order for this path computation to be case of Inter-AS TE, in order for this path computation to be
meaningful, a metric normalization between ASes may be required. One meaningful, metric normalization between ASes may be required. One
solution to avoid IGP metric modification would be for the Service solution to avoid IGP metric modification would be for the Service
Providers to agree on a TE metric normalization scheme and use the TE Providers to agree on a TE metric normalization scheme and use the TE
metric for TE LSP path computation (in that case, this must be metric for TE LSP path computation (in that case, this must be
requested in the PCEP Path computation request) thanks to the METRIC requested in the PCEP Path computation request) using the METRIC
object (defined in [I-D.ietf-pce-pcep]). object (defined in [I-D.ietf-pce-pcep]).
14. Manageability Considerations 14. Manageability Considerations
This section follows the guidance of This section follows the guidance of
[I-D.ietf-pce-manageability-requirements]. [I-D.ietf-pce-manageability-requirements].
14.1. Control of Function and Policy 14.1. Control of Function And Policy
The only configurable item is the support of the BRPC procedure on a The only configurable item is the support of the BRPC procedure on a
PCE. The support of the BRPC procedure by the PCE MAY be controlled PCE. The support of the BRPC procedure by the PCE MAY be controlled
by a policy module governing the conditions under which a PCE should by a policy module governing the conditions under which a PCE should
participate to the BRPC procedure (origin of the requests, number of participate to the BRPC procedure (origin of the requests, number of
requests per second, ...). If the BRPC is not supported/allowed on a requests per second, ...). If the BRPC is not supported/allowed on a
PCE, it MUST send a PCErr message as specified in Section 9. PCE, it MUST send a PCErr message as specified in Section 9.
14.2. Information and Data Models 14.2. Information And Data Models
A BRPC MIB module will be specified in a separate document. A BRPC MIB module will be specified in a separate document.
14.3. Liveness Detection and Monitoring 14.3. Liveness Detection and Monitoring
The BRPC procedure is a Multiple-PCE path computation technique and The BRPC procedure is a Multiple-PCE path computation technique and
as such a set of PCEs are involved in the path computation chain. If as such a set of PCEs are involved in the path computation chain. If
the path computation chain is not operational either because at least the path computation chain is not operational either because at least
one PCE does not support the BRPC procedure or because one of the one PCE does not support the BRPC procedure or because one of the
PCEs that must be involved in the path computation chain is not PCEs that must be involved in the path computation chain is not
available, procedures are defined to report such failures in available, procedures are defined to report such failures in
Section 9 and Section 12 respectively. Furthermore, a built-in Section 9 and Section 12 respectively. Furthermore, a built-in
diagnostic tool to check the availability and performances of a PCE diagnostic tool to check the availability and performances of a PCE
chain is defined in [I-D.ietf-pce-monitoring]. chain is defined in [I-D.ietf-pce-monitoring].
14.4. Verifying Correct Operation 14.4. Verifying Correct Operation
Verifying the correct operation of BRPC can be done by looking at the Verifying the correct operation of BRPC can be performed by
TEDs related to the various domains traversed by a TE LSP at the time monitoring a set of parameters. A BRPC implementation SHOULD provide
the BRPC procedure was invoked and verify that the path computed by the following parameters:
the BRPC procedure is the expected optimal inter-domain constrained
path (the path that would be obtained in the absence of multiple o Number of successful BRPC Procedure completions on a per PCE peer
domains). basis,
o Number of BRPC procedure completion failures because the VSPT flag
was not recognized (on a per PCE peer basis),
o Number of BRPC procedure completetion failures because the BRPC
procedure was not supported (on a per PCE peer basis),
14.5. Requirements on Other Protocols and Functional Components 14.5. Requirements on Other Protocols and Functional Components
The BRPC procedure does not put any new requirements on other The BRPC procedure does not put any new requirements on other
protocol. That said, since the BRPC procedure relies on the PCEP protocol. That said, since the BRPC procedure relies on the PCEP
protocol, there is a dependency between BRPC and PCEP; consequently protocol, there is a dependency between BRPC and PCEP; consequently
the BRPC procedure inherently makes use of the management functions the BRPC procedure inherently makes use of the management functions
developed for PCEP. developed for PCEP.
14.6. Impact on Network Operation 14.6. Impact on Network Operation
The BRPC procedure does not have any significant impact on network The BRPC procedure does not have any significant impact on network
operation: indeed, BRPC is a Multiple-PCE path computation scheme as operation: indeed, BRPC is a Multiple-PCE path computation scheme as
defined in [RFC4655] and does not differ from any other path defined in [RFC4655] and does not differ from any other path
computation request. computation request.
14.7. Path computation chain monitoring 14.7. Path Computation Chain Monitoring
[I-D.ietf-pce-monitoring] specifies a set of mechanisms that can be [I-D.ietf-pce-monitoring] specifies a set of mechanisms that can be
used to gather PCE state metrics. Because BRPC is a Multiple-PCE used to gather PCE state metrics. Because BRPC is a Multiple-PCE
path computation techniques, such mechanism could be advantageously path computation techniques, such mechanism could be advantageously
used in the context of the BRPC procedure to check the liveness of used in the context of the BRPC procedure to check the liveness of
the path computation chain, locate a faulty component, monitor the the path computation chain, locate a faulty component, monitor the
overall performance and so on. overall performance and so on.
15. IANA Considerations 15. IANA Considerations
15.1. New flag of the RP object 15.1. New Flag Of The RP Object
A new flag of the RP object (specified in [I-D.ietf-pce-pcep]) is A new flag of the RP object (specified in [I-D.ietf-pce-pcep]) is
defined in this document. defined in this document.
VSPT Flag VSPT Flag
Bit Number Name Flag Reference Bit Number Name Flag Reference
7 VSPT This document 7 VSPT This document
15.2. new Error-Type and Error-Value 15.2. New Error-Type And Error-Value
A new Error-Type is defined in this document (Error-Type and Error- A new Error-Type is defined in this document (Error-Type and Error-
value to be assigned by IANA). value to be assigned by IANA).
Error-type Meaning Reference Error-type Meaning Reference
13 BRPC procedure completion failure This document 13 BRPC procedure completion failure This document
Error-value Error-value
1: BRPC procedure not supported by 1: BRPC procedure not supported by
one a PCE along the domain path one a PCE along the domain path
15.3. New flag of the NO-PATH-VECTOR TLV 15.3. New Flag Of The NO-PATH-VECTOR TLV
A new flag of the NO-PATH-VECTOR TLV defined in [I-D.ietf-pce-pcep]) A new flag of the NO-PATH-VECTOR TLV defined in [I-D.ietf-pce-pcep])
is specified in this document. is specified in this document.
Bit number Meaning Reference Bit number Meaning Reference
4 BRPC Path computation This document 4 BRPC Path computation This document
chain unavailable chain unavailable
16. Security Considerations 16. Security Considerations
skipping to change at page 15, line 38 skipping to change at page 16, line 22
policy module governing the conditions under which a PCE should policy module governing the conditions under which a PCE should
participate to the BRPC procedure. participate to the BRPC procedure.
The BRPC procedure does not increase the information exchanged The BRPC procedure does not increase the information exchanged
between ASes and preserves topology confidentiality, in compliance between ASes and preserves topology confidentiality, in compliance
with [RFC4105] and [RFC4216]. with [RFC4105] and [RFC4216].
17. Acknowledgements 17. Acknowledgements
The authors would like to thank Arthi Ayyangar, Dimitri The authors would like to thank Arthi Ayyangar, Dimitri
Papadimitriou, Siva Sivabalan and Meral Shirazipour for their useful Papadimitriou, Siva Sivabalan, Meral Shirazipour and Mach Chen for
comments. A special thank to Adrian Farrel for his useful comments their useful comments. A special thank to Adrian Farrel for his
and suggestions. useful comments and suggestions.
18. References 18. References
18.1. Normative References 18.1. Normative References
[I-D.ietf-pce-pcep] [I-D.ietf-pce-pcep]
Ayyangar, A., Oki, E., Atlas, A., Dolganow, A., Ikejiri, Ayyangar, A., Oki, E., Atlas, A., Dolganow, A., Ikejiri,
Y., Kumaki, K., Vasseur, J., and J. Roux, "Path Y., Kumaki, K., Vasseur, J., and J. Roux, "Path
Computation Element (PCE) communication Protocol (PCEP)", Computation Element (PCE) Communication Protocol (PCEP)",
draft-ietf-pce-pcep-09 (work in progress), November 2007. draft-ietf-pce-pcep-12 (work in progress), March 2008.
[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.
[RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
Element (PCE)-Based Architecture", RFC 4655, August 2006.
18.2. Informative References 18.2. Informative References
[I-D.ietf-ccamp-inter-domain-pd-path-comp]
Vasseur, J., Ayyangar, A., and R. Zhang, "A Per-domain
path computation method for establishing Inter-domain
Traffic Engineering (TE) Label Switched Paths (LSPs)",
draft-ietf-ccamp-inter-domain-pd-path-comp-06 (work in
progress), November 2007.
[I-D.ietf-ccamp-inter-domain-rsvp-te]
Ayyangar, A., "Inter domain Multiprotocol Label Switching
(MPLS) and Generalized MPLS (GMPLS) Traffic Engineering -
RSVP-TE extensions",
draft-ietf-ccamp-inter-domain-rsvp-te-07 (work in
progress), September 2007.
[I-D.ietf-ccamp-isis-interas-te-extension] [I-D.ietf-ccamp-isis-interas-te-extension]
Chen, M. and R. Zhang, "ISIS Extensions in Support of Chen, M. and R. Zhang, "ISIS Extensions in Support of
Inter-AS Multiprotocol Label Switching (MPLS) and Inter-AS Multiprotocol Label Switching (MPLS) and
Generalized MPLS (GMPLS) Traffic Engineering", Generalized MPLS (GMPLS) Traffic Engineering",
draft-ietf-ccamp-isis-interas-te-extension-00 (work in draft-ietf-ccamp-isis-interas-te-extension-00 (work in
progress), February 2008. progress), February 2008.
[I-D.ietf-ccamp-ospf-interas-te-extension] [I-D.ietf-ccamp-ospf-interas-te-extension]
Chen, M., Zhang, R., and X. Duan, "OSPF Extensions in Chen, M., Zhang, R., and X. Duan, "OSPF Extensions in
Support of Inter-AS Multiprotocol Label Switching (MPLS) Support of Inter-AS Multiprotocol Label Switching (MPLS)
and Generalized MPLS (GMPLS) Traffic Engineering", and Generalized MPLS (GMPLS) Traffic Engineering",
draft-ietf-ccamp-ospf-interas-te-extension-02 (work in draft-ietf-ccamp-ospf-interas-te-extension-02 (work in
progress), November 2007. progress), November 2007.
[I-D.ietf-pce-manageability-requirements] [I-D.ietf-pce-manageability-requirements]
Farrel, A., "Inclusion of Manageability Sections in PCE Farrel, A., "Inclusion of Manageability Sections in PCE
Working Group Drafts", Working Group Drafts",
draft-ietf-pce-manageability-requirements-02 (work in draft-ietf-pce-manageability-requirements-03 (work in
progress), August 2007. progress), February 2008.
[I-D.ietf-pce-monitoring] [I-D.ietf-pce-monitoring]
Vasseur, J., Roux, J., and Y. Ikejiri, "A set of Vasseur, J., Roux, J., and Y. Ikejiri, "A set of
monitoring tools for Path Computation Element based monitoring tools for Path Computation Element based
Architecture", draft-ietf-pce-monitoring-01 (work in Architecture", draft-ietf-pce-monitoring-01 (work in
progress), February 2008. progress), February 2008.
[I-D.ietf-pce-path-key] [I-D.ietf-pce-path-key]
Bradford, R., "Preserving Topology Confidentiality in Bradford, R. and J. Vasseur, "Preserving Topology
Inter-Domain Path Computation Using a Key-Based Confidentiality in Inter-Domain Path Computation Using a
Mechanism", draft-ietf-pce-path-key-01 (work in progress), Key-Based Mechanism", draft-ietf-pce-path-key-02 (work in
September 2007. progress), February 2008.
[RFC2702] Awduche, D., Malcolm, J., Agogbua, J., O'Dell, M., and J. [RFC2702] Awduche, D., Malcolm, J., Agogbua, J., O'Dell, M., and J.
McManus, "Requirements for Traffic Engineering Over MPLS", McManus, "Requirements for Traffic Engineering Over MPLS",
RFC 2702, September 1999. RFC 2702, September 1999.
[RFC4105] Le Roux, J., Vasseur, J., and J. Boyle, "Requirements for [RFC4105] Le Roux, J., Vasseur, J., and J. Boyle, "Requirements for
Inter-Area MPLS Traffic Engineering", RFC 4105, June 2005. Inter-Area MPLS Traffic Engineering", RFC 4105, June 2005.
[RFC4216] Zhang, R. and J. Vasseur, "MPLS Inter-Autonomous System [RFC4216] Zhang, R. and J. Vasseur, "MPLS Inter-Autonomous System
(AS) Traffic Engineering (TE) Requirements", RFC 4216, (AS) Traffic Engineering (TE) Requirements", RFC 4216,
November 2005. November 2005.
[RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
Element (PCE)-Based Architecture", RFC 4655, August 2006.
[RFC4726] Farrel, A., Vasseur, J., and A. Ayyangar, "A Framework for [RFC4726] Farrel, A., Vasseur, J., and A. Ayyangar, "A Framework for
Inter-Domain Multiprotocol Label Switching Traffic Inter-Domain Multiprotocol Label Switching Traffic
Engineering", RFC 4726, November 2006. Engineering", RFC 4726, November 2006.
[RFC5088] Le Roux, JL., Vasseur, JP., Ikejiri, Y., and R. Zhang, [RFC5088] Le Roux, JL., Vasseur, JP., Ikejiri, Y., and R. Zhang,
"OSPF Protocol Extensions for Path Computation Element "OSPF Protocol Extensions for Path Computation Element
(PCE) Discovery", RFC 5088, January 2008. (PCE) Discovery", RFC 5088, January 2008.
[RFC5089] Le Roux, JL., Vasseur, JP., Ikejiri, Y., and R. Zhang, [RFC5089] Le Roux, JL., Vasseur, JP., Ikejiri, Y., and R. Zhang,
"IS-IS Protocol Extensions for Path Computation Element "IS-IS Protocol Extensions for Path Computation Element
(PCE) Discovery", RFC 5089, January 2008. (PCE) Discovery", RFC 5089, January 2008.
Appendix A. Proposed Status and Discussion [To Be Removed Upon [RFC5152] Vasseur, JP., Ayyangar, A., and R. Zhang, "A Per-Domain
Publication] Path Computation Method for Establishing Inter-Domain
Traffic Engineering (TE) Label Switched Paths (LSPs)",
This Internet-Draft is being submitted for eventual publication as an RFC 5152, February 2008.
RFC with a proposed status of Standard. Discussion of this proposal
should take place on the following mailing list: pce@ietf.org.
Authors' Addresses Authors' Addresses
JP Vasseur (editor) JP Vasseur (editor)
Cisco Systems, Inc Cisco Systems, Inc
1414 Massachusetts Avenue 1414 Massachusetts Avenue
Boxborough, MA 01719 Boxborough, MA 01719
USA USA
Email: jpv@cisco.com Email: jpv@cisco.com
skipping to change at page 19, line 44 skipping to change at line 833
attempt made to obtain a general license or permission for the use of attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr. http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at this standard. Please address the information to the IETF at
ietf-ipr@ietf.org. ietf-ipr@ietf.org.
Acknowledgment
Funding for the RFC Editor function is provided by the IETF
Administrative Support Activity (IASA).
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