I agree with you. Michael Procter wrote: > Proxy E should forward the request. This has been explained numerous > times already in this thread, but I'll summarise the key points again. > > 1. A Proxy checks for Max-Forwards:0 when it receives a message. > 2. A Proxy does not check for Max-Forwards:0 when it sends a message. > 3. A User Agent does not check Max-Forwards at all. > > Your argument that Proxy E should reject the message because it has > already visited 5 nodes is incorrect. It should only be rejected if it > was received with Max-Forwards:0. Note also that the header is called > 'Max-Forwards' and not 'Max-Hops' or 'Max-Nodes'. Proxies engage in > forwarding, but UAs do not. > > Michael > > >> -----Original Message----- >> From: [EMAIL PROTECTED] >> > [mailto:sip-implementors- > >> [EMAIL PROTECTED] On Behalf Of Subramanya >> Sent: 15 November 2006 14:30 >> To: Kasturi Narayanan >> Cc: ysong; sip-implementors >> Subject: Re: [Sip-implementors] FW: Query on max-forwards counts >> >> When a request reaches the proxy, if mf becomes 0 once proxy >> > decrements > >> the mf,then it means it has already hopped n number of times right, >> > then > >> why proxy should send to next hop. >> >> i mean, see this example where mf is 5 >> mf=5 mf =4 mf =3 mf =2 mf =1 mf >> > =0 > >> UA1--> Proxy A--> Proxy B--> Proxy C-->Proxy D--> Proxy E-->UA2 >> >> Now at Proxy E mf is 0, means it has already visited 5 nodes, so it >> shdn't be forwarded anymore,so proxy E shd return with 483 response. >> >> Please correct me if i am wrong. >> >> -Subramanya >> >> >> Kasturi Narayanan wrote: >> >>> The approach suggested by Robert Sparks solves the problem but >>> > creates > >> an un-necessary hop when the sender knows for sure that it going to be >> dropped by the Receiver (since it is sending with mf=0). >> >>> Kasturi >>> >>> -----Original Message----- >>> From: Song, Youngsun [mailto:[EMAIL PROTECTED] >>> Sent: Monday, November 13, 2006 9:22 AM >>> To: [email protected] >>> Subject: [Sip-implementors] FW: Query on max-forwards counts >>> >>> Hi, >>> >>> Please see the attached response from Robert Sparks regarding this >>> query. (FYI, I had also sent him a separate email...) >>> Per his response, Proxy-B should forward the request to UA-B. >>> >>> Thanks to all who has taken the time to respond to my query, >>> YoungSun >>> >>> >>> >>> >>>> -----Original Message----- >>>> From: Robert Sparks [mailto:[EMAIL PROTECTED] >>>> Sent: Monday, November 13, 2006 9:12 AM >>>> To: Song, Youngsun >>>> Subject: Re: [Sip-implementors] Query on max-forwards counts >>>> >>>> See page 95, item 3. >>>> >>>> You reject when you receive, not before you send. >>>> You reject when you receive a max-forwards of 0, not when you >>>> receive a max-forwards of 1. >>>> >>>> RjS >>>> >>>> >>>> >>>>>>> -----Original Message----- >>>>>>> >>>>>>> >>>>>> From: [EMAIL PROTECTED] >>>>>> [mailto:[EMAIL PROTECTED] On >>>>>> >>>>>> >>>> Behalf Of Song, >>>> >>>> >>>>>> Youngsun >>>>>> Sent: Friday, November 10, 2006 11:19 AM >>>>>> To: [email protected] >>>>>> Subject: [Sip-implementors] Query on max-forwards counts >>>>>> >>>>>> Hi, >>>>>> >>>>>> I have a clarification question on the following statement >>>>>> >>>>>> >>>> in Section >>>> >>>> >>>>>> 8.1.1.6 of RFC3261 regarding when a proxy should send a 483 and >>>>>> whether the number of hops includes the destination hop. >>>>>> >>>>>> "The Max-Forwards header field serves to limit the number >>>>>> >>>>>> >>>> of hops a >>>> >>>> >>>>>> request can transit on the way to its destination. It >>>>>> >>>>>> >>>> consists of an >>>> >>>> >>>>>> integer that is decremented by one at each hop. If the >>>>>> >>>>>> >>>> Max-Forwards >>>> >>>> >>>>>> value reaches 0 before the request reaches its >>>>>> >>>>>> >>>> destination, it will >>>> >>>> >>>>>> be rejected with a 483(Too Many Hops) error response." >>>>>> >>>>>> >>>>>> Consider the following flow: (mf=max-forwards) >>>>>> >>>>>> >>>>>> UA-A --- INVITE (mf=2) ---> Proxy-A ---- INVITE (mf=1) >>>>>> >>>>>> >>>> ---> Proxy-B >>>> >>>> >>>>>> ---- INVITE (mf=0) ---> UA-B >>>>>> >>>>>> >>>>>> In the flow above, should Proxy-B forward the INVITE with >>>>>> max-forwards=0 to UA-B or should it reject the request with 483? >>>>>> >>>>>> Thanks for your help in advance, >>>>>> YoungSun >>>>>> >>>>>> _______________________________________________ >>>>>> Sip-implementors mailing list >>>>>> [email protected] >>>>>> https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors >>>>>> >>>>>> >>>>>> >>> _______________________________________________ >>> Sip-implementors mailing list >>> [email protected] >>> https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors >>> >>> >>> _______________________________________________ >>> Sip-implementors mailing list >>> [email protected] >>> https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors >>> >>> >>> >>> >> _______________________________________________ >> Sip-implementors mailing list >> [email protected] >> https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors >> > > _______________________________________________ > Sip-implementors mailing list > [email protected] > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > > >
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