Subject: Re: Minutes

From: Masataka Ohta <[email-masked]>
Date: Fri, 25 Apr 97 23:25:29 JST

> Attached are the minutes I planned to forward to the ietf tomorrow
> 
> Regards,
> 
> Hal

Thank you.

> Masataka's presentation was on "Stable QoS Aggregation".  Masataka pointed
> out that there is a problem when aggregating QoS metric information from
> smaller links in a domain with links of larger capacity.  Outside the domain,
> the information about the smaller links could be lost.  There was some dis-
> cussion about whether to advertise optimistic or pessimistic capacities but
> the differences could be significant.	 Masataka proposed using RSVP PATH mes-
> sages to help ameliorate this problem.

As Eric asked me to provide summary of my presentation within a week or
two, here is a little more detailed ones.

							Masataka Ohta

Masataka's presentation was on "Stable and Scalable QoS Aggregation".

Masataka pointed out that, aggregated link QoS can be stable, if
an aggregated area has several parallel links with comparable
resources and the advertised aggregated value is lower than
actual resource of several links. He also presented that QoS LSA
of WDMxed 100 parallel OC-192 (9.6Gbps) can be super-stable,
as it can be almost always advertised that the link can support
2.4Gbps of flow.

Finally, he presented a concept of FAQ (First Aggregated QoS). While
an area or a domain have various internal bandwidth (and other types of
resources), it is impossible to advertise such source specific information
that only bandwidthes for transit traffic can be scalably flooded. But, for
a specific flow, it is important for accurate QoS routing to know the
first (viewed from the sender) hop QoS to the exit router of the area or
domain. The QoS information arounde receivers is not a problem with receiver
initiated join, where receiver-local information is available to related
parties. The FAQ is a proposal to carry such informatin in RSVP PATH messages,
which is the scalable transport for flow/sender specific information.

     Sender1  Sender2  Sender3
	\	|	/
	 \	|10Mbps/
	  \	|     /
    100Mbps\	|    / 64Kbps
	    \	|   /
	     \	|  /
	      \ | /
	       \|/	     10Gbps
	     Transit Router------------> Other area B
		|
		|
		| 10Gbps
		|
		V
	Other area A

	Unaggregated Link QoS

			     10Gbps
	     Transit Router------------> Other area B
		|
		|
		| 10Gbps
		|
		V
	Other area A

	Aggregated Link QoS

The discussion on FAQ was whether we should be pessimistic or
optimistic when there are multiple parallel transit links with
poor intra-area or -domain connectivity between the links and
Masataka thinks pessimistic advertisement is OK, because intra
-area or -domain connectivity is expected to be good enough.