RE: [Sipping] Congestion Header
"Malas, Daryl" <Daryl.Malas@Level3.com> Mon, 01 May 2006 23:14 UTC
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Subject: RE: [Sipping] Congestion Header
Date: Mon, 01 May 2006 17:14:06 -0600
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Thread-Topic: [Sipping] Congestion Header
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From: "Malas, Daryl" <Daryl.Malas@Level3.com>
To: Janet P Gunn <jgunn6@csc.com>
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Comments inline... Daryl M. daryl.malas@level3.com Ernest Hemingway - "Never mistake motion for action." -----Original Message----- From: Janet P Gunn [mailto:jgunn6@csc.com] Sent: Sunday, April 30, 2006 5:03 PM To: Malas, Daryl Cc: Nguyen, An P CIV NCS NC2; sipping@ietf.org Subject: RE: [Sipping] Congestion Header "Emergency" It is my understanding- based on emails and discussion at the IETF meeting- that REQ 13 " REQ 13: The mechanism must allow a proxy to prioritize requests, so that certain ones, such as call for emergency services, are still processed." was intended to allow the proxy to prioritize requests based on any criteria chosen by the network operator. Emergency calls (both ECRIT-type emergency calls and ETS-type emergency calls) are presented as an example, but such prioritization could be based on many other criteria. For instance, a plausible congestion policy would be to prioritize so that all messages associated with a session establishment "in progress" are still processed, but other messages (e.g. REGISTER, INVITE) are blocked. Trunk congestion- This may just be my lack of SIP expertise, but I am a little bit confused by the use of this congestion header to indicate a trunk group utilization level (at a TDM gateway). In 4412 it says: "If there is not enough bandwidth, or if there is an insufficient number of trunks, a 488 (Not Acceptable Here) response indicates that the RP actor is rejecting the request due to media path availability, such as insufficient gateway resources. In that case, [RFC3261] advises that a 488 response SHOULD include a 'Warning' header field with a reason for the rejection; warning code 370 (Insufficient Bandwidth) is typical." Is the congestion header intended to replace the 488 response, or is it intended to convey additional information (beyond that provided by the 370 warning code) in the 488 response. [Malas] The congestion header would preferably be provided prior to a 488 response, allowing the upstream proxy to alleviate (if possible) a traffic burden on the TDM gateway. It can do this as described in the document. Congestion levels You have specified a large number of "congestion levels" CPU 0, 1, 2, 3, 4 Application: 0, 1, 2, 3, 4 Network: 0, 1, 2, 3, 4 Memory: 0, 1, 2, 3, 4 Disk: 0, 1, 2, 3, 4 TG: 0, 1, 2, 3, 4 (General) 0, 1, 2, 3, 4 This seems more specificity than is needed. When a device is severely congested, it usually isn't a good idea to spend precious resources calculating the utilization of each aspect of the system. Most of the (proprietary) congestion notification systems that I am familiar with use a single easily computable overall level of congestion, such as the lengths of specific internal queues, or the X%ile of time in (internal) queue (both subject to hysteresis). The recipient of the congestion message only needs to know which messages to send, and which not to send. it doesn't need to know the details of which specific subsystems are causing congestion. [Malas] Only one system-descr header would be included per proxy congestion header information. It is optional, and is not required in the congestion header. The only required information is congestion and level unless additional proxy information is included...then a server ID is associated with additional information. Why is the "retry after" permitted only at level 4? Even at lower congestion levels, some messages may need to be deferred. [Malas] I suppose it's up to the working group to decide if a retry-after header is desirable at all levels. If it is, I can easily change this. [Malas] Thanks for the feedback. Janet ------------------------------------------------------------------------ ------------------------------------------------------------------------ -------------------------------- This is a PRIVATE message. If you are not the intended recipient, please delete without copying and kindly advise us by e-mail of the mistake in delivery. NOTE: Regardless of content, this e-mail shall not operate to bind CSC to any order or other contract unless pursuant to explicit written agreement or government initiative expressly permitting the use of e-mail for such purpose. ------------------------------------------------------------------------ ------------------------------------------------------------------------ -------------------------------- "Malas, Daryl" <Daryl.Malas@Level3.com> wrote on 04/26/2006 12:33:45 PM: > An, > > Yes, and any ETS labels added or modified denoting an emergency services > request should be taken into consideration in the same manner as > described. > > --Daryl M. > > -----Original Message----- > From: Nguyen, An P CIV NCS NC2 [mailto:an.p.nguyen@dhs.gov] > Sent: Wednesday, April 26, 2006 9:32 AM > To: Malas, Daryl > Cc: sipping@ietf.org > Subject: RE: [Sipping] Congestion Header > > > Daryl, > > Just a question for clarification: Section 5.3 of the draft talks about > "emergency services". Do they include Emergency Telecommunications > Services in the IEPREP WG? > > Thanks, > > An > > -----Original Message----- > From: Malas, Daryl [mailto:Daryl.Malas@Level3.com] > Sent: Tuesday, April 25, 2006 10:53 PM > To: sipping@ietf.org > Subject: RE: [Sipping] Congestion Header > > > FYI...for those who review the Congestion Header draft, I am aware some > of the quote marks were inadvertently converted to question marks during > the document conversion. I will correct those in an updated revision. > > Thanks...--Daryl > > I also noticed the link was broken, so I'll try it again. > > http://www.ietf.org/internet-drafts/draft-malas-sipping-congestion-heade > r-00.txt > > > -----Original Message----- > From: Malas, Daryl > Sent: Tuesday, April 25, 2006 7:06 PM > To: sipping@ietf.org > Subject: [Sipping] Congestion Header > > Hello, > > We wrote a draft to resolve the common overload issues as identified by > Rosenberg's work in progress "draft-rosenberg-sipping-overload-reqs-00". > > > Title : The Session Initiation Protocol (SIP) CONGESTION > Header Field > Author(s) : D. Malas, et al. > Filename : draft-malas-sipping-congestion-header-00.txt > > A URL for this Internet-Draft is: > http://www.ietf.org/internet-drafts/draft-malas-sipping-congestion-heade > r-00.txt > > We would appreciate feedback regarding the draft to see if the approach > is sound, and can be further refined providing a solid method for > alleviating this issue. > > Thanks, > > Daryl > > _______________________________________________ > Sipping mailing list https://www1.ietf.org/mailman/listinfo/sipping > This list is for NEW development of the application of SIP > Use sip-implementors@cs.columbia.edu for questions on current sip > Use sip@ietf.org for new developments of core SIP > > _______________________________________________ > Sipping mailing list https://www1.ietf.org/mailman/listinfo/sipping > This list is for NEW development of the application of SIP > Use sip-implementors@cs.columbia.edu for questions on current sip > Use sip@ietf.org for new developments of core SIP > > _______________________________________________ > Sipping mailing list https://www1.ietf.org/mailman/listinfo/sipping > This list is for NEW development of the application of SIP > Use sip-implementors@cs.columbia.edu for questions on current sip > Use sip@ietf.org for new developments of core SIP _______________________________________________ Sipping mailing list https://www1.ietf.org/mailman/listinfo/sipping This list is for NEW development of the application of SIP Use sip-implementors@cs.columbia.edu for questions on current sip Use sip@ietf.org for new developments of core SIP
- RE: [Sipping] Congestion Header Malas, Daryl
- [Sipping] Congestion Header Malas, Daryl
- RE: [Sipping] Congestion Header Malas, Daryl
- Re: [Sipping] Congestion Header Paul Kyzivat
- RE: [Sipping] Congestion Header Malas, Daryl
- RE: [Sipping] Congestion Header Janet P Gunn
- RE: [Sipping] Congestion Header Malas, Daryl