Subject: Re: [PCN] O+M section

From: Bob Briscoe <[email-masked]>
Date: Tue, 20 Nov 2007 18:08:55 +0000

Tina,

I just helped Phil re-write the OAM section of
draft-ietf-pcn-architecture-02.txt just posted.

We included most of the suggestions in your text sent back in Jul below,
but in a more discursive and less normative form, given this is an
architecture doc, rather than an OAM stds track doc (taking general
advice from a w-g co-chairs on what the charter wanted on OAM). We also
added a fair bit of new material as you will see.

We'd appreciate a review of the new text (if not the whole draft), given
people interested in OAM are hard to come by.

-----------

I also wanted to explain the reason for omitting two whole chunks of
ideas:

1) Address configuration details

This needs adding to 5.7 on Addressing as we've been discussing offlist.
It would be too complex to record all the configuration permutations in
the OAM section of this overall architecture draft - that will need doing
separately for each different scenario.

2) Per-aggregate stats collected by boundary nodes

These fell into two categories:

- flow-level

- packet-level

Instead, we covered these all under the catch-all paragraph
below:

"Monitoring of performance factors measurable from /outside/ the PCN
domain will be no different with PCN than with any other packet-based
flow admission control system, both at the flow level (blocking
probability etc) and the  packet level (jitter [RFC3393][Y.1541],
loss rate [RFC4656], mean opinion score [P.800], etc)."

Essentially, we figured that if a domain wasn't collecting any specific
stats across the domain without PCN, there would be no need to start
collecting them with PCN.

Thus we omitted mention of the specific flow-level per-aggregate and
packet-level per-aggregate stats you had in there (flows offered,
admitted, terminated, no of packets sent, no of packets received at each
marking level, number of reports sent etc).

Essentially the reasoning was that an operator /might/ want to collect
any combination of stats, but we couldn't think what they would use these
particular ones for. So we confined the discussion to stuff:

- that will be different with PCN

- and that we could describe a reasonable motivation for collecting.

We figured an operator could specify if they wanted all these other
possible stats in an invitation to tender, rather than an IETF
doc.

------------

I have just noticed that I omitted the useful ideas on recording
cumulative durations of faults. These would naturally fit where we talk
of recording near-misses and faults in the Fault OAM section. We should
add this to the next draft. Sorry about that.

If you feel strongly that anything else we omitted should have been in
there, just shout.

Bob

At 15:29 25/07/2007, Tina TSOU wrote:

Hi
all,

As promised, attached please find the O+M
section which was discussed in the arch designing team.

Hope it can be a basis or starting point as the
O+M part in the ML.

B. R.

Tina

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Bob Briscoe, <[email-masked]>
Networks Research Centre, BT Research

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