Subject: RE: [Sipping] Updated overload requirements draft

From: "Widjaja, Indra \(Indra\)" <[email-masked]>
Date: Fri, 3 Nov 2006 14:41:48 -0600

Hi:

I have the following questions in the simulation model section.

1) A sentence on page 14 states: "Similarly, messages sent from the home
proxy to the edge proxies are distributed uniformly amongst them." 
Does this imply that we're not using the destination of a message to
explicitly route the message to the edge proxy? Also, are we restricting
the simulation model to uniform traffic pattern only?

2) Section 6.2 adopts a model where different transactions are assumed
to be independent, which on one hand seems desirable because of its
simplicity. On the other hand, it's not clear what the precise effect of
this assumption is on the actual performance.

3) Should the metrics for comparison purposes be added?

Regards,
Indra

-----Original Message-----
From: Jonathan Rosenberg [mailto:[email-masked]] 
Sent: Sunday, October 22, 2006 10:45 AM
To: IETF Sipping List
Subject: [Sipping] Updated overload requirements draft

I've submitted an update to the overload requirements document. Until it

appears in the archives, you can pick it up here:

http://www.jdrosen.net/papers/draft-rosenberg-sipping-overload-reqs-02.t
xt

The main change is that I've added a network simulation model, including

  a network model, proxy processing model, and traffic and simulation 
parameters. This model has been requested at the last few meetings. It 
serves several purposes:

1. to allow experts from the congestion control community to understand 
the problem and help recommend and model solutions

2. to allow for a baseline model to use in comparing proposed solutions

Thanks,
Jonathan R.
-- 
Jonathan D. Rosenberg, Ph.D.                   600 Lanidex Plaza
Cisco Fellow                                   Parsippany, NJ 07054-2711
Cisco Systems
[email-masked]                              FAX:   (973) 952-5050
http://www.jdrosen.net                         PHONE: (973) 952-5000
http://www.cisco.com

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_______________________________________________
Sipping mailing list  https://www1.ietf.org/mailman/listinfo/sipping
This list is for NEW development of the application of SIP
Use [email-masked] for questions on current sip
Use [email-masked] for new developments of core SIP

---

From: Jonathan Rosenberg <[email-masked]>
Date: Mon, 06 Nov 2006 17:33:59 -0500

> the simulation model to uniform traffic pattern only?

Yes. I don't think that it adds much in terms of understanding this 
problem. Typically calls would be uniformly distributed amongst the edge 
proxies anyway, in a real network where proper registration processing 
was being used.

> this assumption is on the actual performance.

I didn't see any reason why it impacts the overall model.

> 3) Should the metrics for comparison purposes be added?

Thats a good idea; the main metrics are the goodput (the number of 
successfully completed transactions - ones not rejected for reasons of 
overload) vs the offered load, and the throuput (total number of 
transactions that generated any response, including ones due to overload).

-Jonathan R.