Subject: [mpls] Consolidated Responses to MPLS-RT for draft-fuxh-mpls-delay-loss-te-framework

From: "Mcdysan, David E" <[email-masked]>
Date: Fri, 10 Aug 2012 06:12:38 -0400

Hi,

As mentioned in the meeting, below are the consolidated responses from the
subject draft presented on Friday, Aug 3 at Vancouver, augmented with a
few comments from the meeting for your review, comment and discussion.

Opinions were also invited in the meeting as to where the best place in
the IETF would be for the two proposed drafts (requirements, framework)
would be.

Thanks again to the MPLS Review Team (MPLS-RT) Stewart Bryant, Daniel King
and Jia He for their review and comments.

Dave
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Overall Response to MPLS-RT Review

* Split Text into two Drafts
  - Problem Statement/Requirements:
  - Perform substantial re-write and add new text focusing on problem
statement, context , use case and requirements.
* Framework draft: 
  - Summarize framework to meet requirements using current/proposed
approaches 
  - Document scalability assessment and recommendations
  -Identify any needed protocol development
  - Remove solution specific material
* Change Intended Status from Standards Track to Informational for these
drafts

Specific Responses to MPLS-RT Review

* Node latency: queuing latency
  - Don¹t prohibit solution from considering node latency, range of
problems are:
    - Large geographic separation of nodes, few nodes (e.g.,
trans-oceanic) - link latency a good approximation
    - Small geographic separation of nodes, many nodes node/device latency
very important link may be negligible
    - Medium geographic separation, few-many nodes
      - Recommend usage of both link and node latency
  - To simply things, could resurrect the following from a previous version
    - If certain customers (e.g., financial) care deeply about node
latency, solution may provide configuration knob to the user to let them
add some fixed value of a portion (e.g., one half) node latency to link
latency.

* Proof of Jitter/Delay Variation Accumulation
  - Summarize ITU-T Y.1541 delay variation models and propose simple upper
bounds
    - Additive is very loose upper bound, tighter approximations are known
 but more complex
  - Summarize operational experience with delay variation in real networks

* Measurement of Nodal Latency
  - Describe current and potential methods for measuring nodal latency

€Scalability
  - Need to state domains of applicability and requirements for scaling
    - Wide, Metro, Medium network geography/nodes
    - Number of domains, number/rate of change of inter-domain TE LSPs
  - Major topic of framework draft would be to agree on categorization,
evaluation of current approaches and assessment of applicability and
requirements
  - Requesting refferences on good scalability analyses from previous RFCs
and/or drafts (or other sources)

* Current/Proposed Potentially Applicable IETF Approaches
  - IGP flooding/ state change frequency within one area/level
  - RSVP-TE signaling across multiple domains (area/level, AS) probing,
recording status of previous attempts, retries
    - Global state not known at the origin as in a single IGP area/level.
  - (Stateful) PCE listening to each domain, communicating amongst PCEs in
other domains approximating global state to reduce probing and retries to
improve scalability

* Add requirements on performance measurement/monitoring (e.g.,
delay/loss). In framework, described how existing performance measurement
and monitoring methods could be use to meet requirements