Network Working Group J.L. Le Roux (Editor)
Internet Draft France Telecom
Category: Informational
Expires: November 2006
May 2006
Requirements for Path Computation Element (PCE) Discovery
draft-ietf-pce-discovery-reqs-04.txt
Status of this Memo
By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.
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."
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
This document presents a set of requirements for a Path Computation
Element (PCE) discovery mechanism that would allow a Path Computation
Client (PCC) to discover dynamically and automatically a set of PCEs
along with certain information relevant for PCE selection. It is
intended that solutions that specify procedures and protocols or
extensions to existing protocols for such PCE discovery satisfy these
requirements.
Le Roux et al. Requirements for PCE Discovery [Page 1]
Internet Draft draft-ietf-pce-discovery-reqs-04.txt May 2006
Conventions used in this document
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.
Table of Contents
1. Contributors................................................3
2. Terminology.................................................3
3. Introduction................................................4
4. Problem Statement and Requirements Overview.................5
4.1. Problem Statement...........................................5
4.2. Requirements overview.......................................6
5. Example of application scenario.............................6
6. Detailed Requirements.......................................7
6.1. PCE Information to be disclosed.............................7
6.1.1. General PCE Information (Mandatory support).................8
6.1.1.1. Discovery of PCE Location.................................8
6.1.1.2. Discovery of PCE Domains and Inter-domain Functions.......8
6.1.2. Detailed PCE Information (Optional support).................9
6.1.2.1. Discovery of PCE Capabilities.............................9
6.1.2.2. Discovery of Alternate PCEs...............................9
6.2. Scope of PCE Discovery.....................................10
6.2.1. Inter-AS specific requirements.............................10
6.3. PCE Information Synchronization............................11
6.4. Discovery of PCE deactivation..............................11
6.5. Policy Support.............................................11
6.6. Security Requirements......................................12
6.7. Extensibility..............................................12
6.8. Scalability................................................12
6.9. Operational orders of magnitudes...........................13
6.10. Manageability considerations...............................13
7. Security Considerations....................................13
8. Acknowledgments............................................13
9. References.................................................14
9.1. Normative references.......................................14
9.2. Informative references.....................................14
10. Authors' Addresses:........................................14
11. Intellectual Property Statement............................15
Le Roux et al. [Page 2]
Internet Draft draft-ietf-pce-discovery-reqs-04.txt May 2006
1. Contributors
The following are the authors that contributed to the present
document:
Jean-Louis Le Roux (France Telecom)
Paul Mabey (Qwest Communications)
Eiji Oki (NTT)
Richard Rabbat (Fujitsu)
Ting Wo Chung (Bell Canada)
Raymond Zhang (BT Infonet)
2. Terminology
Terminology used in this document
LSR: Label Switch Router
TE-LSP: Traffic Engineered Label Switched Path
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.
PCC: Path Computation Client: any client application requesting a
path computation to be performed by a Path Computation Element.
IGP Area: OSPF Area or ISIS level/area
ABR: IGP Area Border Router (OSPF ABR or ISIS L1L2 router)
AS: Autonomous System
ASBR: AS Border Router
Intra-area TE LSP: A TE LSP whose path does not cross IGP area
boundaries.
Inter-area TE LSP: A TE LSP whose path transits through two or more
IGP areas.
Inter-AS MPLS TE LSP: A TE LSP whose path transits through two or
more ASs or sub-ASs (BGP confederations).
Domain: any collection of network elements within a common sphere of
address management or path computational responsibility. Examples of
domains include IGP areas and Autonomous Systems.
Le Roux et al. [Page 3]
Internet Draft draft-ietf-pce-discovery-reqs-04.txt May 2006
3. Introduction
The PCE-based network Architecture [PCE-ARCH] defines a Path
Computation Element (PCE) as an entity capable of computing TE-LSP
paths based on a network graph, and applying computational
constraints. A PCE serves path computation requests sent by Path
Computation Clients (PCC).
A PCC is a client application requesting a path computation to be
performed by a PCE. This can be, for instance, an LSR requesting a
path for a TE-LSP for which it is the head-end, or a PCE requesting a
path computation of another PCE (inter-PCE communication). The
communication between a PCC and a PCE requires a client-server
protocol whose generic requirements are listed in [PCE-COM-REQ].
The PCE based architecture requires, that a PCC be aware of the
location of one or more PCEs in its domain, and also potentially of
some PCEs in other domains, e.g. in case of inter-domain path
computation.
In that context it would be highly desirable to define a mechanism
for automatic and dynamic PCE discovery, which would allow PCCs to
automatically discover a set of PCEs, to determine additional
information required for PCE selection, and to dynamically detect new
PCEs or any modification of the PCEs' information. This includes the
discovery by a PCC of a set of one or more PCEs in its domain, and
potentially in some other domains. The latter is a desirable function
in the case of inter-domain path computation, for example.
This document lists a set of functional requirements for such an
automatic and dynamic PCE discovery mechanism. Section 4 points out
the problem statement. Section 5 illustrates an application scenario.
Finally, section 6 addresses detailed requirements.
It is intended that solutions that specify procedures and protocols
or protocol extensions for PCE discovery satisfy these requirements.
There is no intent either to specify solution-specific requirements
or to make any assumption on the protocols that could be used for the
discovery.
Note that requirements listed in this document apply equally to PCEs
that are capable of computing paths in MPLS-TE-enabled networks and
PCEs that are capable of computing paths in GMPLS-enabled networks
(and PCEs capable of both).
It is also important to note that the notion of a PCC encompasses a
PCE acting as PCC when requesting a path computation of another PCE
(inter-PCE communication). Hence, this document does not make the
distinction between PCE discovery by PCCs and PCE discovery by PCEs.
Le Roux et al. [Page 4]
Internet Draft draft-ietf-pce-discovery-reqs-04.txt May 2006
4. Problem Statement and Requirements Overview
4.1. Problem Statement
A routing domain may, in practice, contain multiple PCEs:
- The path computation load may be balanced among a set of PCEs
to improve scalability;
- For the purpose of redundancy, primary and backup PCEs may be
used;
- PCEs may have distinct path computation capabilities (multi-
constrained path computation, backup path computation, etc.);
- In an inter-domain context there can be several PCEs with
distinct inter-domain functions (inter-area, inter-AS, inter-
layer), each PCE being responsible for path computation in one or
more domains.
In order to allow for effective PCE selection by PCCs, that is to
select the appropriate PCE based on its capabilities and perform
efficient load balancing of requests, a PCC needs to know the
location of PCEs in its domain, along with some information relevant
to PCE selection, and also potentially needs to know the location of
some PCEs in other domains, for inter-domain path computation
purpose.
Such PCE information could be learnt through manual configuration, on
each PCC, of the set of PCEs along with their capabilities. Such a
manual configuration approach may be sufficient, and even desired in
some particular situations, (e.g. inter-AS PCE discovery, where
manual configuration of neighbor PCEs may be preferred for security
reasons), but it obviously faces several limitations:
- This may imply a substantial configuration overhead;
- This would not allow a PCC to dynamically detect that a new PCE is
available, that an existing PCE is no longer available, or that
there is a change in the PCE's information.
Furthermore, as with any manual configuration approach, there is a
risk of configuration errors.
As an example, in a multi-area network made up of one backbone area
and N peripheral areas, and where inter-area MPLS-TE path computation
relies on multiple-PCE path computation with ABRs acting as PCEs, the
backbone area would comprise at least N PCEs, and the configuration
of PCC would be too cumbersome (e.g. in existing multi-area networks,
N can be beyond fifty).
Hence, an automated PCE discovery mechanism allowing a PCC to
dynamically discover a set of PCEs is highly desirable.
Le Roux et al. [Page 5]
Internet Draft draft-ietf-pce-discovery-reqs-04.txt May 2006
4.2. Requirements overview
A PCE discovery mechanism that satisfies the requirements set forth
in this document MUST allow a PCC to automatically discover the
location of one or more of the PCEs in its domain.
Where inter-domain path computation is required, the PCE discovery
method MUST allow a PCC to automatically discover the location of
PCEs in other domains that can assist with inter-domain path
computation.
A PCE discovery mechanism MUST allow a PCC to discover the set of one
or more domains where a PCE has TE topology visibility and can
compute paths. It MUST also allow the discovery of the potential
inter-domain path computation functions of a PCE (inter-area, inter-
AS, inter-layer, etc.).
A PCE discovery mechanism MUST allow the control of the discovery
scope, that is the set of one or more domains (areas, ASs) where
information related to a given PCE has to be disclosed.
A PCE discovery mechanism MUST allow PCCs in a given discovery scope
to dynamically discover that a new PCE has appeared or that there is
a change in PCE's information.
A PCE discovery mechanism MUST allow PCCs to dynamically discover
that a PCE is no longer available.
A PCE discovery MUST support security procedures. In particular, key
consideration MUST be given in terms of how to establish a trust
model for PCE discovery.
OPTIONALLY a PCE discovery mechanism MAY be used so as to disclose a
set of detailed PCE capabilities so that the PCC may make advanced
and informed choices about which PCE to use.
5. Example of application scenario
<----------------AS1--------------------> <----AS2---
Area 1 Area 0 Area 2
R1---------R3-----R5-------R6-----------R9----------R11----R13
| | | | |
| | | | |
R2---------R4-----R7-------R8-----------R10---------R12----R14
|
|
--
|S1|
--
Figure 1
Le Roux et al. [Page 6]
Internet Draft draft-ietf-pce-discovery-reqs-04.txt May 2006
Figure 1 illustrates a multi-area/AS network with several PCEs:
- The ABR R3 is a PCE that can take part in inter area path
computation. It can compute paths in area 1 and area 0;
- The ABR R6 is a PCE that can take part in inter-area path
computation. It can compute paths in area 0 and area2;
- The ASBR R9 is a PCE that can take part in inter-AS path
computation. It is responsible for path computation in AS1 towards
AS2;
- The ASBR R12 is a PCE that can take part in inter-AS path
computation. It is responsible for path computation in AS2 towards
AS1;
- The server S1 is a PCE that can be used to compute diverse paths
and backup paths in area 1.
By meeting the requirements set out in this document, the PCE
discovery mechanism will allow:
- each PCC in areas 1 and 0 to dynamically discover R3, as a PCE for
inter-area path computation, and that R3 can compute paths in area0
and area1;
- each PCC in areas 0 and 2 to dynamically discover R6, as a PCE for
inter-area path computation, and that R6 can compute paths in area2
and area0;
- each PCC in AS1 and one or more PCCs in AS2 to dynamically discover
R9 as a PCE for inter-AS path computation in AS1 towards AS2;
- each PCC in AS2 and one or more PCCs in AS1 to dynamically discover
R12 as a PCE for inter-AS path computation in AS2 towards AS1;
- each PCC in area 1 to dynamically discover S1, as a PCE for intra-
area path computation in area1, and optionally to discover its path
computation capabilities (diverse path computation and backup path
computation).
6. Detailed Requirements
6.1. PCE Information to be disclosed
We distinguish two levels of PCE information to be disclosed by a PCE
discovery mechanism:
- General information. Disclosure MUST be supported by the
PCE discovery mechanism.
- Detailed information. Disclosure MAY be supported by the
PCE discovery mechanism.
The PCE discovery mechanism MUST allow disclosure of general PCE
information that will allow PCCs to select appropriate PCEs. This
comprises discovery of PCE location, PCE domains supported by the
PCEs, and PCE inter-domain functions.
The PCE discovery mechanism MAY also allow disclosure of detailed PCE
information. This comprises any or all information about PCE path
computation capabilities and alternate PCEs. This information is not
part of PCE discovery; this is additional information that can
Le Roux et al. [Page 7]
Internet Draft draft-ietf-pce-discovery-reqs-04.txt May 2006
facilitate the selection of a PCE by a PCC. Support of the exchange
of this information is optional in the context of the PCE discovery
mechanism itself. This does not mean that the availability of this
information is optional in the PCE-based architecture, but such
information could also be obtained by other mechanisms, such as the
PCC-PCE communication protocol.
6.1.1. General PCE Information (Mandatory support)
6.1.1.1. Discovery of PCE Location
The PCE discovery mechanism MUST allow the discovery, for a given
PCE, of the IPv4 and/or IPv6 address to be used to reach the PCE.
This address will typically be a loop-back address that is always
reachable, if there is any connectivity to the PCE.
This address will be used by PCCs to communicate with a PCE, through
a PCC-PCE communication protocol.
6.1.1.2. Discovery of PCE Domains and Inter-domain Functions
Inter-domain path computation is a key application of the PCE
architecture. This can rely on a multiple-PCE path computation, where
PCEs in each domain compute a part of the end-to-end path and
collaborate with each other to find the end-to-end-path. Inter-domain
path computation can also rely on a single-PCE path computation where
a PCE has visibility inside multiple domains and can compute an
entire end-to-end inter-domain path (that is a path from the inter-
domain TE-LSP head-end to the inter-domain TE-LSP tail end).
Hence the PCE discovery mechanism MUST allow the discovery of the set
of one or more domains where a PCE has visibility and can compute
paths. These domains could be identified using a domain identifier:
For instance, an IGP area can be identified by the Area ID (OSPF or
ISIS), and an AS can be identified by the AS number.
Also the PCE discovery mechanism MUST allow discovery of the inter-
domain functions of a PCE, i.e. whether a PCE can be used to compute
or to take part in the computation of end-to-end paths across domain
borders. The inter-domain functions include non exhaustively: inter-
area, inter-AS and inter-layer path computation. Note that these
functions are not mutually exclusive.
Note that the inter-domain functions are not necessarily inferred
from the set of domains where a PCE has visibility. For instance a
PCE may have visibility limited to a single domain, but may be able
to take part into the computation of inter-domain paths, by
collaborating with PCEs in other domains. Conversely, a PCE may have
visibility in multiple domains but the operator may not want that the
PCE be used for inter-domain path computations.
Le Roux et al. [Page 8]
Internet Draft draft-ietf-pce-discovery-reqs-04.txt May 2006
The PCE discovery mechanisms MUST also allow discovery of the set of
one or more domains toward which a PCE can compute paths. For
instance in an inter-AS path computation context, there may be
several PCEs in an AS, each one responsible for taking part in the
computation of inter-AS paths toward a set of one or more destination
ASs, and a PCC must discover the destination ASs each PCE is
responsible for.
6.1.2. Detailed PCE Information (Optional support)
6.1.2.1. Discovery of PCE Capabilities
In the case where there are several PCEs with distinct capabilities
available, a PCC has to select one or more appropriate PCEs.
For that purpose the PCE discovery mechanism MAY support the
disclosure of some detailed PCE capabilities.
For the sake of illustration this could include the following path
computation related PCE capabilities:
- The link constraints supported: e.g. bandwidth, affinities.
- The path constraints supported: maximum IGP/TE cost, maximum hop
count;
- The objective functions supported: e.g. shortest path, widest path;
- The capability to compute multiple correlated paths: e.g. diverse
paths, load balanced paths;
- The capability to compute bidirectional paths;
- The GMPLS technology specific constraints supported: e.g. the
supported interface switching capabilities, encoding types.
And this could also include some specific PCE capabilities:
- The capability to handle request prioritization;
- The maximum size of a request message;
- The maximum number of path requests in a request message;
- The PCE computation power (static parameters to be used for
weighted load balancing of requests).
Such information regarding PCE capabilities could then be used by a
PCC to select an appropriate PCE from a list of candidate PCEs.
Note that the exact definition and description of PCE capabilities is
out of the scope of this document. It is expected that this will be
described in one or more separate documents which may be application
specific.
6.1.2.2. Discovery of Alternate PCEs
In the case of a PCE failure, a PCC has to select another PCE, if one
is available. It could be useful in various situations, for a PCE to
indicate a set of one or more alternate PCEs that can be selected in
case the given PCE fails.
Le Roux et al. [Page 9]
Internet Draft draft-ietf-pce-discovery-reqs-04.txt May 2006
Hence the PCE Discovery mechanism MAY allow the discovery, for a
given PCE, of the location of one or more assigned alternate PCEs.
The PCE Discovery mechanism MAY also allow the discovery, for a given
PCE, of the set of one or more PCEs for which it acts as alternate
PCE.
6.2. Scope of PCE Discovery
The PCE Discovery mechanism MUST allow control of the scope of the
PCE information disclosure on a per PCE basis. In other words it MUST
allow control of to which PCC or group of PCCs the information
related to a PCE may be disclosed.
The choice for the discovery scope of a given PCE MUST include at
least the followings settings:
- All PCCs in a single IGP area
- All PCCs in a set of adjacent IGP areas
- All PCCs in a single AS
- All PCCs in a set of ASs
- A set of one or more PCCs in a set of one or more ASs
In particular, this also implies that the PCE Discovery mechanism
MUST allow for the discovery of PCE information across IGP areas and
across AS boundaries.
The discovery scope MUST be configurable on a per PCE basis.
It MUST be possible to deactivate PCE discovery on a per PCE basis.
6.2.1. Inter-AS specific requirements
When using a PCE-based approach for inter-AS path computation, a PCC
in one AS may need to learn information related to inter-AS capable
PCEs located in other ASs. For that purpose, and as pointed out in
the previous section, the PCE discovery mechanism MUST allow
disclosure of information related to inter-AS capable PCEs across AS
boundaries.
Such inter-AS PCE discovery must be carefully controlled. For
security and confidentiality reasons, particularly in an inter-
provider context, the discovery mechanism MUST allow the discovery
scope to be limited to a set of ASs and MUST also provide control of
the PCE information to be disclosed across ASs. This is achieved by
applying policies (See also section 6.4). This implies the capability
to contain a PCE advertisement to a restricted set of one or more
Le Roux et al. [Page 10]
Internet Draft draft-ietf-pce-discovery-reqs-04.txt May 2006
ASs, and to filter and translate any PCE parameter (PCE domains, PCE
inter-domain functions, PCE capabilities, etc.) in disclosures that
cross AS borders. For the sake of illustration, it may be useful to
disclose detailed PCE information (such as detailed capabilities)
locally in the PCE's AS but only general information (such as
location and supported domains) in other ASs.
6.3. PCE Information Synchronization
The PCE discovery mechanism MUST allow a PCC to discover any change
in the information related to a PCE that it has previously
discovered. This includes changes to both general information (e.g.
a change in the PCE domains supported), and detailed information if
supported (e.g. a modification of the PCE's capabilities).
In addition, the PCE discovery mechanism MUST allow to dynamically
discover new PCEs in a given discovery scope.
Note that there is no requirement for real-time detection of these
changes, the PCE Discovery Mechanism SHOULD rather allow discovery of
these changes in an order of magnitude of 60 seconds, and the
operator should have the ability to configure the Discovery delay.
Note that PCE information is relatively static, and is expected to be
fairly stable and to not change frequently.
6.4. Discovery of PCE deactivation
The PCE discovery mechanism MUST allow a PCC to discover when a PCE
that it has previously discovered is no longer alive or is
deactivated. This may help reducing or avoiding path computation
service disruption.
Note that there is no requirement for real-time detection of PCE
failure/deactivation, the PCE Discovery Mechanism SHOULD rather allow
such discovery in an order of magnitude of 60 seconds, and the
operator should have the ability to configure the Discovery delay.
6.5. Policy Support
The PCE Discovery mechanism MUST allow for policies to restrict the
discovery scope to a set of authorized domains, to control and
restrict the type and nature of the information to be disclosed, and
also to filter and translate some information at domains borders. It
MUST be possible to apply these policies on a per PCE basis.
The way these policies could be managed is out of the scope of this
document.
Note that the Discovery mechanisms MUST allow disclosing policy
information so as to control the disclosure policies at domain
boundaries.
Le Roux et al. [Page 11]
Internet Draft draft-ietf-pce-discovery-reqs-04.txt May 2006
Also, it MUST be possible to apply different policies when disclosing
PCE information to different domains.
6.6. Security Requirements
The five major threats related to PCE discovery mechanisms are:
- Impersonation of PCE;
- Interception of PCE discovery information (sniffing);
- Falsification of PCE discovery information;
- Information disclosure to non-authorized PCCs (PCC spoofing).
- DoS Attacks
Note that security of the PCE Discovery procedures is of particular
importance in an inter-AS context, where PCE discovery may increase
the vulnerability to attacks and the consequences of these attacks.
Hence mechanisms MUST be defined to ensure authenticity, integrity,
privacy, and containment of PCE discovery information:
- There MUST be a mechanism to authenticate discovery information;
- There MUST be a mechanism to verify discovery information
integrity;
- There MUST be a mechanism to encrypt discovery information;
- There MUST be a mechanism to restrict the scope of discovery to a
set of authorized PCCs and to filter PCE information disclosed
at domain boundaries (as per defined in 6.5).
Mechanisms MUST be defined in order to limit the impact of a
DoS attack on the PCE discovery procedure (e.g. filter out excessive
PCE information change and flapping PCEs). Note also that DOS
attacks may be either accidental (caused by a mis-behaving
PCE system) or intentional. As discussed in [PCE-COM-REQ] such
mechanisms may include packet filtering, rate limiting, no
promiscuous listening, and where applicable use of private addresses
spaces.
Also, key consideration MUST be given in terms of how to establish a
trust model for PCE discovery. The PCE discovery mechanism MUST
explicitly support a specific set of one or more trust models.
6.7. Extensibility
The PCE discovery mechanism MUST be flexible and extensible so as to
easily allow for the inclusion of additional PCE information that
could be defined in the future.
6.8. Scalability
The PCE discovery mechanism MUST be designed to scale well with an
increase of any of the following parameters:
- Number of PCCs discovering a given PCE;
- Number of PCEs to be discovered by a given PCC;
- Number of domains in the discovery scope.
Le Roux et al. [Page 12]
Internet Draft draft-ietf-pce-discovery-reqs-04.txt May 2006
The PCE discovery mechanism MUST NOT have an adverse effect in the
performance of other protocols (especially routing and signaling)
already operating in the network.
Note that there is no scalability requirement with regards to the
amount of information to be exchanged.
Information disclosed in the PCE discovery mechanism is relatively
static. Changes in PCE information may occur as result of PCE
configuration updates, PCE deployment/activation or PCE
deactivation/suppression, and should not occur as a result of the PCE
activity itself. Hence, this information is quite stable and will not
change frequently.
6.9. Operational orders of magnitudes
This section gives minimum order of magnitude estimates of what the
PCE discovery mechanism should support.
- Number of PCCs discovering a given PCE: 1000
- Number of PCEs to be discovered by a given PCC: 100
6.10. Manageability considerations
Manageability of PCE discovery MUST addresses the following
considerations:
- need for a MIB module for PCE discovery;
- configuration implications for the protocol.
7. Security Considerations
This document is a requirement document and hence does not raise by
itself any particular security issue.
A set of security requirements that MUST be addressed when
considering the design and deployment of a PCE Discovery mechanism
have been identified in section 6.6.
8. Acknowledgments
We would like to thank Benoit Fondeviole, Thomas Morin, Emile
Stephan, Jean-Philippe Vasseur, Dean Cheng, Adrian Farrel, Renhai
Zhang, Mohamed Boucadair, Eric Gray, Igor Bryskin, Dimitri
Papadimitriou, Arthi Ayyangar, Andrew Dolganow, Lou Berger, Nabil
Bitar, Kenji Kumaki and Ross Callon for their useful comments and
suggestions.
Le Roux et al. [Page 13]
Internet Draft draft-ietf-pce-discovery-reqs-04.txt May 2006
9. References
9.1. Normative references
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[PCE-ARCH] Farrel, A., Vasseur, J.P., Ash, J., "Path Computation
Element (PCE) Architecture", draft-ietf-pce-architecture, work in
progress.
9.2. Informative references
[PCE-COM-REQ] Ash, J., Le Roux, J.L., "PCE Communication Protocol
Generic Requirements", draft-ietf-pce-comm-protocol-gen-reqs, work in
progress.
10. Authors' Addresses:
Jean-Louis Le Roux (Editor)
France Telecom
2, avenue Pierre-Marzin
22307 Lannion Cedex
FRANCE
Email: jeanlouis.leroux@francetelecom.com
Paul Mabey
Qwest Communications
950 17th Street,
Denver, CO 80202,
USA
Email: pmabey@qwest.com
Eiji Oki
NTT
Midori-cho 3-9-11
Musashino-shi, Tokyo 180-8585,
JAPAN
Email: oki.eiji@lab.ntt.co.jp
Richard Rabbat
Fujitsu Laboratories of America
1240 East Arques Ave, MS 345
Sunnyvale, CA 94085
USA
Email: richard@us.fujitsu.com
Ting Wo Chung
Bell Canada
181 Bay Street, Suite 350
Toronto, Ontario, M5J 2T3
Le Roux et al. [Page 14]
Internet Draft draft-ietf-pce-discovery-reqs-04.txt May 2006
CANADA,
Email: ting_wo.chung@bell.ca
Raymond Zhang
BT Infonet
2160 E. Grand Ave.
El Segundo, CA 90025
USA
Email: raymond_zhang@infonet.com
11. Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.
Disclaimer of Validity
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Copyright Statement
Copyright (C) The Internet Society (2006). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights.
Le Roux et al. [Page 15]
