Re: [MEDIACTRL] [sip-overload] WGLC: draft-ietf-soc-overload-design

"Parthasarathi R (partr)" <> Mon, 30 August 2010 05:43 UTC

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Date: Mon, 30 Aug 2010 11:12:42 +0530
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From: "Parthasarathi R (partr)" <>
To: "Janet P Gunn" <>, "Volker Hilt" <>
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Cc: "Paul Jones \(paulej\)" <>,,
Subject: Re: [MEDIACTRL] [sip-overload] WGLC: draft-ietf-soc-overload-design
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My point is same as Janet's. I wish that SIP overload design document
has to explicitly indicate about congestion collapse in SIP server due
to other loads (like RTP message) is outside the scope of the document.
Without this text in the document, the implementers of SIP servers with
other load handling may be mislead.


From: Janet P Gunn [] 
Sent: Monday, August 30, 2010 2:04 AM
To: Volker Hilt
Cc:; Parthasarathi R (partr); Paul Jones (paulej);;
Subject: Re: [sip-overload] WGLC: draft-ietf-soc-overload-design

I guess the points are: 
1- If a SIP actor is experiencing overload (regardless of whether the
overload is due to "too many SIP messages" or something else entirely)
it needs to reduce the rate at which SIP messages arrive at the SIP
actor (the focus of this document). 
2- If the overload is largely due to something other than SIP messages,
then ONLY reducing the arrival of SIP messages may not significantly
reduce the overload, and you may still have congestion collapse. 
3- For devices which are SIP actors, and also  serve other loads (e.g.
RTP, database lookup, ISUP gateway), it is to be hoped that there is an
overload control mechanism  for each type of traffic, and that the
mechanisms are coordinated in a sensible way (so that no one type of
traffic is starved out by the others).  But, other than a passing
comment, that is out of scope for a document on SIP Overload Control. 


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From: 	Volker Hilt <> 
To: 	"Parthasarathi R (partr)" <> 
Cc: 	"" <>,
"" <>, "Paul Jones \(paulej\)"
Date: 	08/29/2010 04:16 PM 
Subject: 	Re: [sip-overload] WGLC: draft-ietf-soc-overload-design



the CPU load of a SIP server can increase for many reasons, not only the

processing of RTP packets. For example, the system might start the daily

backup of a database, apply patches, run a virus scan or launch another 

If any of these events leads to a shortage of CPU cycles in which the 
SIP server may not be able to process all incoming SIP messages, it 
should use overload control to reduce the number of SIP messages.



On 8/29/2010 4:06 PM, Parthasarathi R (partr) wrote:
> Volker,
> I doubt whether the current draft will serve for all SIP servers. I'm
> taking the example of B2BUA with media (RTP)topology hiding
> functionality and there is no DSP, DS0 or DISK resource involved.
> Server experiences an overload of SIP message not just because of
> incoming SIP messages but also due to the incoming RTP messages and
> messages flow varies depend upon the dialog (call) hold time whereas
> there may not any SIP message when the dialog is established. SIP
> processor mentioned in the system model of this draft may be shared
> physical processor with RTP messages or other protocols messages. We
> have the problem in incorporating the current SIP overload design in
> media handling SIP devices.
> I'm including mediactrl to hear their experience with SIP overload
> design and mediactrl combined SIP implementation.
> Thanks
> Partha
> *From:* Volker Hilt [
<> ]
> *Sent:* Sun 8/29/2010 11:43 PM
> *To:* Parthasarathi R (partr)
> *Cc:* Salvatore Loreto;
> *Subject:* Re: [sip-overload] WGLC: draft-ietf-soc-overload-design
> Partha,
> the design document discusses problems related to the overload of SIP
> messages. Any server that processes SIP messages can experience an
> overload of SIP messages. Therefore, the discussions in the draft
> to all servers that are involved in SIP message processing.
> SIP servers that also provide media handling services may need
> mechanisms to signal that they are out of trunk lines, DSP processors,
> storage capacity for voicmails, etc. These mechanisms will often be
> needed at times when the servers can still process SIP messages. These
> mechanisms are out of scope for the working group as discussed.
> Thanks,
> Volker
> On 8/29/2010 1:21 PM, Parthasarathi R (partr) wrote:
>  > Sal/Volker,
>  > The design document is designed for dedicated SIP signaling servers
>  > experiments are done based on the dedicated servers. The same
design may
>  > not scale for SIP server with media handling. As per IETF-78
>  > SIP servers with media handling
>  > (draft-partha-soc-overload-resource-availability-00,
>  > draft-jones-sip-overload-sce-00) is outside the scope of this
>  > group. I think that it is better to indicate the scope of this
>  > design is for "dedicated SIP servers" only and does not include
>  > servers with SIP. Please let me know your opinion on the same.
>  > Thanks
>  > Partha
>  >
>  > *From:* on behalf of Salvatore Loreto
>  > *Sent:* Mon 8/23/2010 4:54 AM
>  > *To:*
>  > *Cc:* Volker Hilt
>  > *Subject:* [sip-overload] WGLC: draft-ietf-soc-overload-design
>  >
>  > [as chair]
>  >
>  > the draft has been update to address all the concerns/suggestions
>  > have been raised during
>  > the F2F meeting in Maastricht:
>  >
>  >
>  >
>  >
>  > the chairs believe the document has no remaining open issues, and
>  > ready for WG last call evaluation.
>  >
>  > Today we are starting a two-weeks working group last call.
>  > This call end on September 5th.
>  >
>  > comments and especially full and deep reviews of the draft are
>  > appreciate.
>  >
>  >
>  > cheers
>  > Sal
>  >
>  > --
>  > Salvatore Loreto
>  >
>  >
>  > _______________________________________________
>  > sip-overload mailing list
>  >
>  >
>  >
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