Subject: Path Computation Element (PCE) BOF

From: "Adrian Farrel" <[email-masked]>
Date: Thu, 17 Jun 2004 22:01:25 +0100

Hi,

We will be holding a BOF in San Diego under the care of the Routing Area.

Please see the description, a draft agenda, and proposed charter below.

We'd welcome any thoughts for additions to the agenda, and any pointers to existing drafts that you consider already fit within this scope.

If you have views for or against, please bring them to the BOF where we will hopefully have time to air them fully.

Thanks,
Adrian and JP

====
 Path Computation Element BOF (PCE BOF) Agenda
60th IETF, San Diego, August 2004
 
 Routing Area Ads: Alex Zinin ([email-masked]),
                  Bill Fenner ([email-masked])

BOF Chairs: JP Vasseur ([email-masked]),
            Adrian Farrel ([email-masked])

Description:
In certain MPLS TE networks it may be beneficial or desirable to have path 
computation performed by a distinct node (termed the Path Computation 
Element  PCE) that is not the LSR that needs to know the path. This BOF 
examines the scope of such function, what extensions to existing protocols 
might required, what additional protocols may need to be developed, and 
whether there is cuase and support for this work within the IETF.

---
 
Proposed BOF agenda
1) Introduction, admin, statement of objectives of the BOF (10 minutes)
2) Overview of PCE-based LSP Path computation (10 minutes)
         - terminology
         - dichotomy (centralized versus distributed, statefull versus 
           stateless, ...)
3) Requirements for PCE-based path computation (5 minutes)
         - for intra-area TE LSP (packet and non packet LSP, multiple 
           criteria optimization techniques, online/offline)
         - for inter-area and inter-AS TE (shared information or 
           collaborative computation)
4) Functional requirements of a PCE-based path computation system  (10 minutes)
         - Framework,
         - Path computation model
         - discovery of PCEs within a network
         - distribution of TE information to PCEs
         - LSR-PCE communication
         - Monitoring and Management (MIBs)
         - Policy/Security/Confidentiality in the context of inter-providers
5) Current status of drafts and early implementations (10 minutes)
6) Why should this be IETF work? (5 minutes)
         - CCAMP or new Working Group?
         - Is this work limited to MPLS-TE? What about BGP route servers?
7) Proposed charter (see below) (10 minutes)
8) Open discussion (50 minutes)
9) Summary and conclusions (10 minutes)

---
 
Proposed WG Charter
 
Organizational Overview
The PCE working group coordinates the work within the IETF of defining the 
 operation of path computation elements within the Internet. Path 
computation elements are responsible for computing paths through IP 
networks for uses such as traffic engineering so that a prime consumer of 
such paths might be an MPLS-TE LSR. Areas of responsibility will include 
the collection of attributes relevant to the computation of paths, the 
discovery by LSRs of available path computation elements, the communication 
with LSRs for the request of path computation, the collaboration between 
path computation elements within the network, and analysis of path 
computation algorithms with a view to ensuring consistency between computed 
paths. The working group will work closely with many working groups in the 
Routing Area including the OSPF, IS-IS, IDR, MPLS and CCAMP working groups.

Working Group Scope
The PCE working group scope includes:
- Definition  of Generalized Traffic Engineered LSP paths computation 
  techniques involving Path Computation Element(s). This includes the intra 
  IGP area, inter IGP area, inter-AS and inter-provider TE LSPs path 
  computation for Point-to-Point, Point-to-Multipoint and 
  Multipoint-to-Multipoint TE LSPs.
- Definition of protocol-independent metrics and constraints defining path 
  quality measurement criteria, algorithm complexity and scalability criteria 
  related to path computation techniques.
- Definition of requirements for communication between LSRs and PCEs 
  including routing extensions in support of PCE discovery techniques within 
  an IGP area and across multiple IGP areas, ASes and Provider networks, and 
  including the development of new protocols or protocol extensions for 
  requesting path computation and supplying responses. Any protocol 
  extensions will developed in conjunction with the working groups in charge 
  of the specific protocols.
- Specification of routing (OSPF, ISIS, BGP) and signalling extensions 
  (RSVP-TE) required by PCE-based path computation techniques. The extensions 
  will developed in conjunction with the working groups in charge of the 
  specific protocols.
- Specification of requirements and protocol extensions related to the 
  policy, security and confidentiality aspects of PCE-based path computation 
  techniques involving PCEs of multiple Providers.
- Definition of MIBs, management procedures related to the protocol 
  extensions defined by the WG

In doing this work, the WG will closely work with at least the following 
other WGs: CCAMP, MPLS, ISIS, OSPF, IDR. The WG will also cooperate with 
the ITU-T and OIF.

Goals and Milestones

Dates for milestones to be decided later.

  Post strawman WG goals and charter.

  Submit WG document defining the framework and applicability of the 
  PCE model.

  Select a single candidate protocol from communication between LSRs 
  and PCEs.

  Submit document(s) that define various path computation models
 
  Submit an analysis document examining the requirements for coherent
  computation techniques and the implication of cooperation between 
  PCEs.

  Submit a document defining the protocol for communication between 
  LSRs and PCEs.

  Submit document(s) defining extensions to routing and signalling 
  protocols necessary to support the use of a PCE model within MPLS
  networks.
 
  Submit a document defining MIB modules for modeling and management 
  of PCE systems.
_______________________________________________
routing-discussion mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/routing-discussion

---

From: "Ash, Gerald R \(Jerry\), ALABS" <[email-masked]>
Date: Fri, 25 Jun 2004 14:01:23 -0500

All,

Please review and comment on "Path Computation Element (PCE) Problem
Statement"
http://www.ietf.org/internet-drafts/draft-ash-pce-problem-statement-00.t
xt.  The PCE is an approach to MPLS traffic engineering that is
applicable to inter-area and inter-AS path computation.  A problem
statement and overview of solution alternatives is provided.  This will
be discussed during the PCE BOF outlined below.

Thanks,
Jerry 

________________________________

From: [email-masked] [mailto:[email-masked]] On
Behalf Of Adrian Farrel
Sent: Thursday, June 17, 2004 5:01 PM
To: [email-masked]; [email-masked]'; [email-masked];
[email-masked]; TEWG
Cc: 'Jean Philippe Vasseur'
Subject: Path Computation Element (PCE) BOF

Hi,
 
We will be holding a BOF in San Diego under the care of the Routing
Area.

We'd welcome any thoughts for additions to the agenda, and any pointers
to existing drafts that you consider already fit within this scope.
 
If you have views for or against, please bring them to the BOF where we
will hopefully have time to air them fully.
 
Thanks,
Adrian and JP
 
====
 
Routing Area Ads: Alex Zinin ([email-masked] <mailto:[email-masked]> ),
                  Bill Fenner ([email-masked]
<mailto:[email-masked]> )

BOF Chairs: JP Vasseur ([email-masked] <mailto:[email-masked]>
),
            Adrian Farrel ([email-masked]
<mailto:[email-masked]> )

Description:
In certain MPLS TE networks it may be beneficial or desirable to have
path 
computation performed by a distinct node (termed the Path Computation 
Element  PCE) that is not the LSR that needs to know the path. This BOF 
examines the scope of such function, what extensions to existing
protocols 
might required, what additional protocols may need to be developed, and 
whether there is cuase and support for this work within the IETF.

---

Proposed BOF agenda
4) Functional requirements of a PCE-based path computation system  (10
minutes)
         - Policy/Security/Confidentiality in the context of
inter-providers
         - Is this work limited to MPLS-TE? What about BGP route
servers?

---

Proposed WG Charter
 
Organizational Overview
The PCE working group coordinates the work within the IETF of defining
the 
operation of path computation elements within the Internet. Path 
computation elements are responsible for computing paths through IP 
networks for uses such as traffic engineering so that a prime consumer
of 
such paths might be an MPLS-TE LSR. Areas of responsibility will include

the collection of attributes relevant to the computation of paths, the 
discovery by LSRs of available path computation elements, the
communication 
with LSRs for the request of path computation, the collaboration between

path computation elements within the network, and analysis of path 
computation algorithms with a view to ensuring consistency between
computed 
paths. The working group will work closely with many working groups in
the 
Routing Area including the OSPF, IS-IS, IDR, MPLS and CCAMP working
groups.

Working Group Scope
The PCE working group scope includes:
- Definition  of Generalized Traffic Engineered LSP paths computation 
  techniques involving Path Computation Element(s). This includes the
intra 
  IGP area, inter IGP area, inter-AS and inter-provider TE LSPs path 
  computation for Point-to-Point, Point-to-Multipoint and 
  Multipoint-to-Multipoint TE LSPs.
- Definition of protocol-independent metrics and constraints defining
path 
  quality measurement criteria, algorithm complexity and scalability
criteria 
  related to path computation techniques.
- Definition of requirements for communication between LSRs and PCEs 
  including routing extensions in support of PCE discovery techniques
within 
  an IGP area and across multiple IGP areas, ASes and Provider networks,
and 
  including the development of new protocols or protocol extensions for 
  requesting path computation and supplying responses. Any protocol 
  extensions will developed in conjunction with the working groups in
charge 
  of the specific protocols.
- Specification of routing (OSPF, ISIS, BGP) and signalling extensions 
  (RSVP-TE) required by PCE-based path computation techniques. The
extensions 
  will developed in conjunction with the working groups in charge of the

  specific protocols.
  policy, security and confidentiality aspects of PCE-based path
computation 

the ITU-T and OIF.

Goals and Milestones