[Sipping] Some questions and comments on draft-rosenberg-sipping-overload-reqs
"Darshan Bildikar" <dbildikar@ipunity.com> Thu, 09 November 2006 05:18 UTC
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From: Darshan Bildikar <dbildikar@ipunity.com>
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Date: Thu, 09 Nov 2006 10:39:26 +0530
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Subject: [Sipping] Some questions and comments on draft-rosenberg-sipping-overload-reqs
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Hello Jonathan, I have some questions/comments on your overload control draft. 1) Section 4.1 - "How, a single request from the client, before timing out, could generate as many as 18 requests and as many responses!" You're probably going for "However" there? Also, I would appreciate if you could clarify how the number of requests/responses could go up to 18. 2) In figure 3, why the assumption that both proxies would try the same set of servers? If P1 and P2 are being used purely for load balancing purposes then what is the likelihood that they would route requests to the same set of servers? 3) REQ 7 states, "The mechanism shall provide a way for an element to throttle the amount of traffic it receives from an upstream element. This throttling shall be graded, so that it is not all or nothing as with the current 503 mechanism. This recognizes the fact that "overload" is not a binary state, and there are degrees of overload." Reading this line I draw the conclusion that the actual throttling (load balancing) is done by the element or rather the up stream element (proxy). Wouldn't it be better rephrased-- "The mechanism shall provide a way for an element to indicate current load parameters to an upstream element such that traffic to the element can be suitably throttled. This throttling shall be graded, so that it is not all or nothing as with the current 503 mechanism. This recognizes the fact that "overload" is not a binary state, and there are degrees of overload." 4) REQ 18 states, "The overload mechanism should be unambiguous about whether a load indication applies to a specific IP address, host, or URI, so that an upstream element can determine the load of the entity to which a request is to be sent" REQ 19 talks about specific SIP method types that might be desirable to process in time of overload. There is also need for throttling based on service type. For example, a server might host Prepaid and CRBT services and might wish to indicate loads separately to proxies based on service type i.e. I cant handle prepaid calls right now but I can handle CRBT. I would however assume that each service would be invoked through a different URI. But is this a safe assumption to make? Also, throttling based on media would be useful. For example, a server might wish to indicate that it cannot handle VIDEO and can only handle AUDIO for a while. The examples above are not an exhaustive list. What I am trying to say is that we need a more EXHAUSTIVE list of parameters based on which over load control can be more "fine grained". Best regards, Darshan _______________________________________________ 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] Re: draft-rosenberg-sipping-overload-re… Jean-Francois Mule
- [Sipping] Some questions and comments on draft-ro… Darshan Bildikar
- Re: [Sipping] Re: draft-rosenberg-sipping-overloa… Volker Hilt