Comments inline... Thanks, Nataraju A B
> -----Original Message----- > From: [EMAIL PROTECTED] [mailto:sip-implementors- > [EMAIL PROTECTED] On Behalf Of Mehul Jain > Sent: Saturday, August 12, 2006 1:13 AM > To: Romel Khan; sip-implementors@cs.columbia.edu > Subject: Re: [Sip-implementors] Max Size of an INVITE message using UDP > > Thanks for the info, but that's the ideal case. In the real network with > gateways, routers and proxies in between, the situation changes. I > wanted to know if there is a known max value in such a real network > scenario. > [ABN] in many cases, the path MTU is about 1400. Your SIP message could be around 1300 bytes. But finally it depends on the path MTU size. > -----Original Message----- > From: Romel Khan [mailto:[EMAIL PROTECTED] > Sent: Friday, August 11, 2006 12:35 PM > To: Mehul Jain; sip-implementors@cs.columbia.edu > Subject: RE: [Sip-implementors] Max Size of an INVITE message using UDP > > Based on the RFC quote, implementation must be able to accept sip > message up to the maximum size allowed per UDP. > UDP header can consume 8 bytes, IP header 20 bytes typically. So SIP > messages could theoretically use 65,535-28 = 65,507 bytes in a > hypothetical environment where there is no MTU constraint. > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Mehul > Jain > Sent: Friday, August 11, 2006 1:41 PM > To: sip-implementors@cs.columbia.edu > Subject: [Sip-implementors] Max Size of an INVITE message using UDP > > Am not clear what is the max supported size of SIP Request (INVITE) sent > using UDP. > Went through the RFC 3261 (18.1.1 Sending Requests ). MTU (1500 Bytes > for Windows) looks to be the limiting factor for UDP, while later its > written that implementations must support messages of the max datagram > size (65,535 bytes). > > Any pointers as to what is the accepted max length in the proxies, > servers etc. > Mehul. > > If a request is within 200 bytes of the path MTU, or if it is larger > than 1300 bytes and the path MTU is unknown, the request MUST be sent > using an RFC 2914 [43] congestion controlled transport protocol, such > as TCP. If this causes a change in the transport protocol from the > one indicated in the top Via, the value in the top Via MUST be > changed. This prevents fragmentation of messages over UDP and > provides congestion control for larger messages. However, > implementations MUST be able to handle messages up to the maximum > datagram packet size. For UDP, this size is 65,535 bytes, including > IP and UDP headers. > > The 200 byte "buffer" between the message size and the MTU accommodates > the fact that the response in SIP can be larger than the request. This > happens due to the addition of Record-Route header field values to the > responses to INVITE, for example. With the extra buffer, the response > can be about 170 bytes larger than the request, and still not be > fragmented on IPv4 (about 30 bytes is consumed by IP/UDP, assuming no > IPSec). 1300 is chosen when path MTU is not known, based on the > assumption of a 1500 byte Ethernet MTU. > _______________________________________________ > Sip-implementors mailing list > Sip-implementors@cs.columbia.edu > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > > _______________________________________________ > Sip-implementors mailing list > Sip-implementors@cs.columbia.edu > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list Sip-implementors@cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
