Networking Working Group JP. Vasseur, Ed.
Internet-Draft Cisco Systems, Inc
Intended status: Standards Track R. Zhang
Expires: September 3, 2007 BT Infonet
N. Bitar
Verizon
JL. Le Roux
France Telecom
March 2, 2007
A Backward Recursive PCE-based Computation (BRPC) procedure to compute
shortest inter-domain Traffic Engineering Label Switched Paths
draft-ietf-pce-brpc-04.txt
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Abstract
The ability to compute shortest constrained Traffic Engineering (TE)
Label Switched Paths (LSPs) in Multiprotocol Label Switching (MPLS)
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and Generalized MPLS (GMPLS) networks across multiple domains (where
a domain is referred to as a collection of network elements within a
common sphere of address management or path computational
responsibility such as IGP areas and Autonomous Systems) has been
identified as a key requirement . This document specifies a
procedure relying on the use of multiple Path Computation Elements
(PCEs) in order to compute such inter-domain shortest constrained
paths along a determined sequence of domains, using a backward
recursive path computation technique while preserving confidentiality
across domains, which is sometimes required when domains are managed
by different Service Providers.
Requirements Language
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 [RFC2119].
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Table of Contents
1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. General assumptions . . . . . . . . . . . . . . . . . . . . . 5
4. BRPC Procedure . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Domain path selection . . . . . . . . . . . . . . . . . . 6
4.2. Mode of Operation . . . . . . . . . . . . . . . . . . . . 7
5. PCEP Protocol Extensions . . . . . . . . . . . . . . . . . . . 9
6. Inter-AS TE Links . . . . . . . . . . . . . . . . . . . . . . 9
7. Usage in conjunction with per-domain path computation . . . . 9
8. BRPC procedure completion failure . . . . . . . . . . . . . . 10
9. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 10
9.1. Diverse end-to-end path computation . . . . . . . . . . . 10
9.2. Path optimality . . . . . . . . . . . . . . . . . . . . . 11
10. Reoptimization of an inter-domain TE LSP . . . . . . . . . . . 11
11. Path Computation failure . . . . . . . . . . . . . . . . . . . 11
12. Metric normalization . . . . . . . . . . . . . . . . . . . . . 12
13. Manageability Considerations . . . . . . . . . . . . . . . . . 12
13.1. Control of Function and Policy . . . . . . . . . . . . . . 12
13.2. Information and Data Models . . . . . . . . . . . . . . . 12
13.3. Liveness Detection and Monitoring . . . . . . . . . . . . 12
13.4. Verifying Correct Operation . . . . . . . . . . . . . . . 13
13.5. Requirements on Other Protocols and Functional
Components . . . . . . . . . . . . . . . . . . . . . . . . 13
13.6. Impact on Network Operation . . . . . . . . . . . . . . . 13
13.7. Path computation chain monitoring . . . . . . . . . . . . 13
14. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
14.1. New flag of the RP object . . . . . . . . . . . . . . . . 13
14.2. New flag of the NO-PATH-VECTOR TLV . . . . . . . . . . . . 14
15. Security Considerations . . . . . . . . . . . . . . . . . . . 14
16. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14
17. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
17.1. Normative References . . . . . . . . . . . . . . . . . . . 14
17.2. Informative References . . . . . . . . . . . . . . . . . . 15
Appendix A. Proposed Status and Discussion [To Be Removed
Upon Publication] . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
Intellectual Property and Copyright Statements . . . . . . . . . . 18
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1. Terminology
ABR: routers used to connect two IGP areas (areas in OSPF or levels
in IS-IS).
ASBR: routers used to connect together ASes of the same or different
Service Provider(s) via one or more Inter-AS links.
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
inter-AS Traffic Engineering.
Entry BN of domain(n): a BN connecting domain(n-1) to domain(n) along
a determined sequence of domains.
Exit BN of domain(n): a BN connecting domain(n) to domain(n+1) along
a determined sequence of domains.
Inter-AS TE LSP: A TE LSP that crosses an AS boundary.
Inter-area TE LSP: A TE LSP that crosses an IGP area boundary.
LSR: Label Switching Router.
LSP: Label Switched Path.
PCC: Path Computation Client. Any client application requesting a
path computation to be performed by the Path Computation Element.
PCE (Path Computation Element): an entity (component, application or
network node) that is capable of computing a network path or route
based on a network graph and applying computational constraints.
PCE(i) is a PCE with the scope of domain(i).
TED: Traffic Engineering Database.
VSPT: Virtual Shortest Path Tree.
The notion of contiguous, stitched and nested TE LSPs is defined in
[RFC4726] and will not be repeated here.
2. Introduction
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.
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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 TE LSP 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
assumptions common to inter-area and inter-AS MPLS TE:
- Each IGP area or AS is assumed to be Traffic Engineering enabled
(i.e. running OSPF-TE or ISIS-TE and RSVP-TE).
- No topology or resource information is distributed between domains
(as mandated per [RFC4105] and [RFC4216]), which is critical to
preserve IGP/BGP scalability and confidentiality.
- While certain constraints like bandwidth can be used across
different domains, other TE constraints like resource affinity,
color, metric, etc. as listed in [RFC2702] could be translated at
domain boundaries. If required, it is assumed that, at the domain
boundary nodes, there will exist some sort of local mapping based on
policy agreement, in order to translate such constraints across
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domain boundaries during the inter-PCE communication process.
- Each AS can be made of several IGP areas. The path computation
procedure described in this document applies to the case of a single
AS made of multiple IGP areas, multiples ASes made of a single IGP
area or any combination of the above. For the sake of simplicity,
each AS will be considered to be made of a single area in this
document. The case of an Inter-AS TE LSP spanning multiple ASes
where some of those ASes are themselves made of multiple IGP areas
can be easily derived from this case by applying the BRPC procedure
described in this document, recursively.
- The domain path (set of domains traversed to reach the destination
domain) is either administratively pre-determined or discovered by
some means that are outside of the scope of this document.
4. BRPC Procedure
The BRPC procedure is a Multiple-PCE path computation technique as
described in [RFC4655]. A possible model consists of hosting the PCE
function on boundary nodes (e.g., ABR or ASBR) but this is not
mandated by the BRPC procedure.
The BRPC procedure does not make any assumptions with regards to the
nature of the inter-domain TE LSP that could be contiguous, nested or
stitched.
Furthermore, no assumption is made on the actual path computation
algorithm in use by a PCE (it can be any variant of CSPF, algorithm
based on linear-programming to solve multi-constraints optimization
problems and so on).
4.1. Domain path selection
The PCE-based BRPC procedure applies to the computation of an optimal
constrained inter-domain TE LSP. The sequence of domains to be
traversed can either be determined a priori or during the path
computation procedure. The BRPC procedure guarantees to compute the
optimal path across a 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 is then
selected.
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4.2. Mode of Operation
Definition of VSPT(i)
In each domain i:
* 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).
* 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).
VSPT(i): MP2P (MultiPoint To Point) tree returned by PCE(i) to
PCE(i-1):
Root (TE LSP destination)
/ 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
and j<= [X-en(i)]
Each link of tree VSPT(i) represents the shortest path between BN-
en(j,i) (identified by its TE Router-ID) and the destination that
satisfies the set of required constraints for the TE LSP (bandwidth,
affinities, ...). These are path segments to reach the destination
from BN-en(j,i).
Note that PCE(i) only considers the entry BNs that provide
connectivity from domain(i-1). That is, the set BN-en(k,i-1) is only
made of those BNs that provide connectivity from domain (i-1) to
domain(i). Furthermore, some BNs may be excluded according to policy
constraints (either due to local policy or policies signaled in the
path computation request).
Step 1: the PCC needs to first determine the PCE capable of serving
its path computation request (this can be done thanks to local
configuration or via IGP discovery (see
[I-D.ietf-pce-disco-proto-ospf] and
[I-D.ietf-pce-disco-proto-isis])). 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 step of the process, the next PCE
can either be statically configured 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 stops and a path computation
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error is returned (see Section 8). If multiple PCEs are discovered,
the PCE may select a subset of these PCEs based on some local
policies or heuristics. Note also that a sequence of PCEs might be
enforced by policy on the PCC and this constraint can be carried in
the PCEP path computation request (as defined in
[I-D.vasseur-pce-monitoring]).
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
destination using a suitable path computation algorithm (e.g. CSPF)
and returns the computed VSPT(n) to PCE(n-1).
Step i:
- For i=n-1 to 2: PCE(i) concatenates the topology of domain(i)
(using its TED) with the received VSPT(i+1). 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). Then PCE(i) computes
VSPT(i) (MP2P (Multi-Point to Point) tree made 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
the source to the destination and returns the corresponding path to
the requesting PCC in the form of a PCRep message as defined in
[I-D.ietf-pce-pcep].
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
listed) or a loose path (in which case only the BR is specified) so
as to preserve confidentiality along with the respective cost. In
the later case, various techniques can used in order to retrieve the
computed explicit paths on a per domain basis during the signaling
process thanks to the use of path keys as described in
[I-D.bradford-pce-path-key].
BRPC guarantees to find the optimal (shortest) constrained inter-
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
principles are also possible.
Note also that in case of ECMP paths, more than one path could be
returned to the requesting LSR.
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5. PCEP Protocol Extensions
The BRPC procedure requires the specification of a new flag of the RP
object carried within the PCReq message (defined in
[I-D.ietf-pce-pcep]), the aim of which is to specify that the
shortest path(s) satisfying the constraints from the destination to
the set of entry boundary nodes are requested (such set of path(s)
forms the downstream VSPT as specified in Section 4.2).
The following new flag of the RP object is defined: VSPT (V) flag:
0x60. When set, this indicates that the PCC requests the computation
of an inter-domain TE LSP using the BRPC procedure.
Because path segment(s) computed by a downstream PCE in the context
of the BRPC procedure must be provided along with their respective
path cost(s), the C flag of the METRIC object carried within the
PCReq message MUST be set. It is the choice of the requester to
appropriately set the O bit of the RP object.
6. Inter-AS TE Links
In the case of Inter-AS TE LSP path computation, the BRPC procedure
requires the knowledge of the traffic engineering attributes of the
Inter-AS TE links: the process by which the PCE acquires this
information is out of the scope of the BRPC procedure (which is
compliant with the PCE architecture defined in [RFC4655]).
That said, a straitghforward solution consists of allowing the ASBRs
to flood the TE information related to the inter-ASBR link(s)
although no IGP TE is enabled over those links (there is no IGP
adjacency over the inter-ASBR links). This allows the PCE of a
domain to get entire TE visibility up to the set of entry ASBRs in
the downstream domain.
7. Usage in conjunction with per-domain path computation
The BRPC procedure may be used to compute path segments in
conjunction with other path computation techniques (such as the per-
domain path computation technique defined in
[I-D.ietf-ccamp-inter-domain-pd-path-comp]) to compute the end-to-end
path. In this case end-to-end path optimality can no longer be
guaranteed.
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8. BRPC procedure completion failure
If the BRPC procedure cannot be completed because a PCE along the
domain path does not support the procedure, a PCErr message MUST be
returned to the upstream PCE with a 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
characterized by an Error-Type which specifies the type of error and
an Error-value that provides additional information about the error
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.
Error-type Meaning
13 BRPC procedure completion failure
Error-value
1: BRPC procedure not supported by one or more PCEs
along the domain path
9. Applicability
As discussed in section Section 3, 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. Among the set of
requirements, both documents indicate the need for some solution
providing the ability to compute an optimal (shortest) constrained
inter-domain TE LSP and to compute a set of diverse inter-domain TE
LSPs.
9.1. Diverse end-to-end path computation
PCEP allows a PCC to request the 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 respectively. Such request MUST
be taken into account by each PCE along the path computation chain
during the VSPT computation. In the context of the BRPC procedure, a
set of diversely routed TE LSP between two LSRs can be computed since
the paths segment(s) of the VSPT are simultaneously computed by a
given PCE. The BRPC procedure allows for the computation of diverse
paths under various objective functions (such as minimizing the sum
of the costs of the N diverse paths, etc) thus avoiding the well-
known "trapping" problem. Indeed, with a 2-step approach consisting
of computing the first path followed by the computation of the second
path after having removed the set of network elements traversed by
the first path (if that does not violate confidentiality
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preservation), one 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 most optimal one with respect to an
objective function such as 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 path computation approach is usually less
efficient in term of signalling delays since it requires two
serialized TE LSP set up.
9.2. Path optimality
BRPC guarantees that the optimal (shortest) constrained inter-domain
path will always be found subject to policy constraints. When
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
more than one BR-en or more than one BR-ex, optimality after some
network change within the domain can only be guaranteed by re-
executing the BRPC procedure.
10. Reoptimization of an inter-domain TE LSP
The ability to reoptimize an existing inter-domain TE LSP path has
been explicitly listed as a requirement in [RFC4105] and [RFC4216].
In the case of a TE LSP reoptimization request, the reoptimization
procedures defined in [I-D.ietf-pce-pcep] apply where the path in use
(if available on the head-end) is provided as part of the path
computation request in order for the PCEs involved in the
reoptimization request to avoid double bandwidth accounting.
11. Path Computation failure
If a PCE requires to relay a path computation request acccording to
the BRPC procedure defined in this document to a downstream PCE and
no such PCE is available, the PCE MUST send a negative path
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,
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
Computation chain unvailable" set.
0x04: BRPC Path computation chain unavailable
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12. Metric normalization
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,
propagation delay or some other combination of link attributes).
Hence, the proposed set of mechanisms always computes the shortest
path across multiple areas obeying the required set of constraints
with respect to a well-specified objective function. Conversely, in
the case of Inter-AS TE, in order for this path computation to be
meaningful, a metric normalization between ASes may be required. One
solution to avoid IGP metric modification would be for the SPs to
agree on a TE metric normalization scheme and use the TE metric for
TE LSP path computation (in that case, this must be requested in the
PCEP Path computation request) thanks to the METRIC object (defined
in [I-D.ietf-pce-pcep]).
13. Manageability Considerations
This section is compliant with
[I-D.ietf-pce-manageability-requirements].
13.1. Control of Function and Policy
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
by a policy module governing the conditions under which a PCE should
participate to the BRPC procedure (origin of the requests, number of
requests per second, ...). If the BRPC is not supported/allowed on a
PCE, it MUST send a PCErr message as specified in Section 8.
13.2. Information and Data Models
A BRPC MIB module will be specified in a separate document.
13.3. Liveness Detection and Monitoring
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
the path computation chain is not operational either because at least
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
available, procedures are defined to report such failures in
Section 8 and Section 11 respectively. Furthermore, a built in
diagnostic tool to check the availability and performances of a PCE
chain is defined in [I-D.vasseur-pce-monitoring].
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13.4. Verifying Correct Operation
Verifying the correct operation of BRPC can be done by looking at the
TEDs related to the various domains traversed by a TE LSP at the time
the BRPC procedure was invoked and verify that the path computed by
the BRPC procedure is the expected optimal path (the path that would
be obtained in the absence of multiple domains).
13.5. Requirements on Other Protocols and Functional Components
The BRPC procedure does not put any new requirements on other
protocol. That said, since the BRPC procedure relies on the PCEP
protocol, there is a dependency between BRPC and PCEP; consequently
the BRPC procedure inherently makes use of the management functions
developped for PCEP.
13.6. Impact on Network Operation
The BRPC procudure does not have any significant impact on network
operation: indeed, BRPC is a Multiple-PCE path computation scheme as
defined in [RFC4655] and does not differ from any other path
computation request.
13.7. Path computation chain monitoring
[I-D.vasseur-pce-monitoring] specifies a set of mechanisms that can
be used to gather PCE state metrics. Because BRPC is a Multiple-PCE
path computation techniques, such mechanims could be advantageously
used in the context of the BRPC procedure to check the liveness of
the path computation chain, locate a faulty component, monitor the
overall performance and so on.
14. IANA Considerations
14.1. New flag of the RP object
A new flag of the RP object (specified in [I-D.ietf-pce-pcep]) is
defined in this document.
Name: VSPT (V)
Bit Number: 10
Value: 0x60
When set, this indicates that the PCC requests the computation of an
inter-domain TE LSP using the BRPC procedure.
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A new Error-Type is defined in this document (Error-Type and Error-
value to be assigned by IANA).
Error-type Meaning
13 BRPC procedure completion failure
Error-value
1: BRPC procedure not supported by one or PCEs
along the domain path
14.2. New flag of the NO-PATH-VECTOR TLV
A new flag of the NO-PATH-VECTOR TLV defined in [I-D.ietf-pce-pcep])
is specified in this document.
Defining RFC: draft-ietf-pce-pcep (to be replaced by RFC number when pusblished)
Name of bit: BRPC Path computation chain unavailable
Bit number (suggested value): 0x04
15. Security Considerations
The BRPC procedure relies on the use of the PCEP protocol and as such
is subjected to the potential attacks listed in section 11 of
[I-D.ietf-pce-pcep]. In addition to the security mechanisms
described in [I-D.ietf-pce-pcep] with regards to spoofing, snooping,
falsification and Denial of Service, an implementation MAY support a
policy module governing the condditions under which a PCE should
participate to the BRPC procedure.
The BRPC procedure does not increase the information exchanged
between ASes and preserves topology confidentiality, in compliance
with [RFC4105] and [RFC4216].
16. Acknowledgements
The authors would like to thank Arthi Ayyangar, Dimitri Papadimitriou
and Siva Sivabalan for their useful comments. A special thank to
Adrian Farrel for his useful comments and suggestions.
17. References
17.1. Normative References
[I-D.ietf-pce-pcep]
Roux, J. and J. Vasseur, "Path Computation Element (PCE)
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communication Protocol (PCEP)", draft-ietf-pce-pcep-06
(work in progress), February 2007.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
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.
17.2. Informative References
[I-D.bradford-pce-path-key]
Bradford, R., "Preserving Topology Confidentiality in
Inter-Domain Path Computation using a key based
mechanism", draft-bradford-pce-path-key-02 (work in
progress), January 2007.
[I-D.ietf-ccamp-inter-domain-pd-path-comp]
Vasseur, J., "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-04 (work in
progress), February 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-05 (work in
progress), March 2007.
[I-D.ietf-pce-disco-proto-isis]
Roux, J., "IS-IS protocol extensions for Path Computation
Element (PCE) Discovery",
draft-ietf-pce-disco-proto-isis-02 (work in progress),
February 2007.
[I-D.ietf-pce-disco-proto-ospf]
Roux, J., "OSPF protocol extensions for Path Computation
Element (PCE) Discovery",
draft-ietf-pce-disco-proto-ospf-02 (work in progress),
February 2007.
[I-D.ietf-pce-manageability-requirements]
Farrel, A., "Inclusion of Manageability Sections in PCE
Working Group Drafts",
draft-ietf-pce-manageability-requirements-01 (work in
progress), March 2007.
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[I-D.vasseur-pce-monitoring]
Roux, J. and J. Vasseur, "A set of monitoring tools for
Path Computation Element based Architecture",
draft-vasseur-pce-monitoring-02 (work in progress),
March 2007.
[RFC2702] Awduche, D., Malcolm, J., Agogbua, J., O'Dell, M., and J.
McManus, "Requirements for Traffic Engineering Over MPLS",
RFC 2702, September 1999.
[RFC4105] Le Roux, J., Vasseur, J., and J. Boyle, "Requirements for
Inter-Area MPLS Traffic Engineering", RFC 4105, June 2005.
[RFC4216] Zhang, R. and J. Vasseur, "MPLS Inter-Autonomous System
(AS) Traffic Engineering (TE) Requirements", RFC 4216,
November 2005.
[RFC4726] Farrel, A., Vasseur, J., and A. Ayyangar, "A Framework for
Inter-Domain Multiprotocol Label Switching Traffic
Engineering", RFC 4726, November 2006.
Appendix A. Proposed Status and Discussion [To Be Removed Upon
Publication]
This Internet-Draft is being submitted for eventual publication as an
RFC with a proposed status of Standard. Discussion of this proposal
should take place on the following mailing list: pce@ietf.org.
Authors' Addresses
JP Vasseur (editor)
Cisco Systems, Inc
1414 Massachusetts Avenue
Boxborough, MA 01719
USA
Email: jpv@cisco.com
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Raymond Zhang
BT Infonet
2160 E. Grand Ave.
El Segundo, CA 90025
USA
Email: raymond_zhang@bt.infonet.com
Nabil Bitar
Verizon
40 Sylvan Road
Waltham, MA 02145
USA
Email: nabil.bitar@verizon.com
JL Le Roux
France Telecom
2, Avenue Pierre-Marzin
Lannion, 22307
FRANCE
Email: jeanlouis.leroux@orange-ft.com
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Vasseur, et al. Expires September 3, 2007 [Page 18]
