1. Daniel King, Old Dog Consulting Adrian Farrel, Old Dog Consulting
The Application of the Path Computation Element Architecture to the Determination of a Sequence of Domains in MPLS & GMPLS draft-king-pce-hierarchy-fwk-02.txt
Daniel King, Old Dog Consulting
Adrian Farrel, Old Dog Consulting
76th IETF Hiroshima

2. Motivation
Using a PCE to compute a path between nodes within a single domain is relatively straightforward
Using a PCE to compute paths across multiple domains requires an additional technique
This document examines techniques to:
Establish the optimum path when the sequence of domains is not known in advance, whilst providing:
Path Diversity
Domain diversity, allowing the selection of paths that share ingress and egress domains, but do not share transit domains
Domain path selection should provide the capability to include or exclude specific border nodes
Utilize typical traffic engineering constraints (hop count, bandwidth, lambda continuity, path cost, etc.)
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3. Hierarchical PCE (recap)
The Parent PCE maintains a topology map
The nodes are the Child domains
The map contains the inter-domain links
The TE capabilities of the links are also known
Parent PCE knows the identify and location of the child PCEs responsible for the Child domains
Statically configured
Domain confidentiality
A Parent PCE is aware of the topology and connections between domains, but is not aware of the contents of the domains
Child domains are completely confidential
One child cannot know the topology of another Child.
Child domains do not know the general domain mesh connectivity
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4. Applicability Inter-domain Path Computation
When the Domain Path is Not Known
ASON architecture (G )
H-PCE mechanism fits well within the ASON routing architecture
Multiple Routing Areas
Multi-level
IGP Areas
Path computation across multi-area networks consisting of a backbone area and various peripheral areas
P2MP and Inter-layer
For future study.
All applications will require further study and the document will be updated accordingly

5. Manageability Control of Function and Policy Parent PCE Child PCE
Policy Control
Need to manage authorization between Parent and Child PCEs
Information and Data Models
Monitoring of parent/child relationships, the use of PCEP between the parent and child
Verifying Correct Operation
Number of Child PCE requests
Number of successful hierarchical PCE procedures completions on a per-PCE-peer basis
Number of hierarchical PCE procedure completion failures on a per- PCE-peer basis
Number of hierarchical PCE procedure requests from unauthorized Child PCEs

6. Summary & Next Steps
Good feedback from IETF 75 and OIF Lannion (October)
The authors intend this work to be scoped within the current charter.
The initial will focus on the application of this model within a small group of domains
The authors believe that this work is now stable
We would like to move the work into the working group
76th IETF Hiroshima