Subject: CPL's timeouts

From: Kenny Hom <[email-masked]>
Date: Wed, 09 Feb 2000 13:34:39 -0800

Regarding the Call Processing Language (CPL) draft, are there default
timeout values for the elements that accept timeout as an argument if
the user does not specify a value?

-- 
Kenny Hom 
Senior Software Engineer
Vovida Networks, 2150 Trade Zone Blvd. 105, San Jose, CA 95131
[W] (408) 941-1790 / [F] (408) 941-1791

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From: Jonathan Rosenberg <[email-masked]>
Date: Fri, 11 Feb 2000 01:09:51 -0500

None defined right now as I recall. I'm not sure there needs to be a
standard default. It might be OK for the proxy to set the default
administratively.

-Jonathan R.

-- 
Jonathan D. Rosenberg                       200 Executive Drive
Chief Scientist                             Suite 120 
dynamicsoft                                 West Orange, NJ 07052
[email-masked]                     FAX:   (732) 741-4778
http://www.cs.columbia.edu/~jdrosen         PHONE: (732) 741-7244
http://www.dynamicsoft.com

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From: Henning Schulzrinne <[email-masked]>
Date: Fri, 11 Feb 2000 07:51:47 -0500

Since CPL scripts can explicitly provide timeouts, server-based defaults
don't offer significant policy control to the server. However, they do
open up weird interoperability issues ("my script worked fine yesterday,
you upgraded the server and suddenly all my calls go to voice mail").
Given that we specify default for parameters in SIP, I would argue that
defaults in the spec aid interoperability and portability of scripts.
Too many tunable server parameters aren't in anybody's interest. Having
default parameters also allows "script testers" to reason about overall
script behavior, e.g., with several proxy attempts, how long will it
take overall until the call gets sent to voicemail.

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From: Jonathan Rosenberg <[email-masked]>
Date: Fri, 11 Feb 2000 11:38:41 -0500

OK; I'll buy this argument. Which tags need timeouts? Isn't it only
proxy? I think perhaps a reasonable default is 30 seconds?

-Jonathan R.

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From: Jonathan Lennox <[email-masked]>
Date: Fri, 11 Feb 2000 11:49:14 -0500 (EST)

> proxy? I think perhaps a reasonable default is 30 seconds?

Proxy's the only case where lack of response (noanswer) and failure are
different.  I don't think we need to worry about setting default timeouts
for location lookup or the like.

-- 
Jonathan Lennox
[email-masked]

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From: Henning Schulzrinne <[email-masked]>
Date: Fri, 11 Feb 2000 13:22:10 -0500

Jonathan Lennox wrote:
> different. 

A wholly unscientific check of call forward no answer seems to put the
detault at 15-20 seconds or three-four rings (18-24 seconds). Not that
it much matters, but 20 s seems to be about right.

> I don't think we need to worry about setting default timeouts

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