Comments inline... Thanks & Regards, Nataraju A.B. > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:sip-implementors- > [EMAIL PROTECTED] On Behalf Of Suresh Rangaswamy > Sent: Saturday, June 17, 2006 2:18 AM > To: sip-implementors > Subject: [Sip-implementors] Question regarding Maximum size of SIP message > > Hi All > > According to RFC 3261 section 18.1.1, SIP over UDP implementation should > be able to send /receive 65535 bytes of packet size. Is this applicable > for all SIP networks or is there any other limits on the size of SIP > message. Basically, If SIP message with large content and content > -length (say 8K or 32K ) is sent, is it guaranteed to reach the > endpoint across the network? > > [ABN] in general SIP stack can try to send any message up to 65535 bytes. But it would finally be limited by the lower layer path MTU. In most of GPRS networks supports MTU of 1300. if the SIP message size goes beyond this number, then the lower layer fragmentation/re-assembly happens and if some of the fragments are lost then effectively whole message would be lost (since the next node can't re-assemble the whole message), hence its recommended to limit the application message to within the path MTU limit.
If this messaging happens "over the air", its better to limit the message size to within 1300 (i.e., path MTU of the particular GPRS network). > > Appreciate any suggestion or thoughts on this from SIP Gurus. > > > > Thanks > > Suresh > > > > 18.1.1 Sending Requests > > The client side of the transport layer is responsible for sending the > > request and receiving responses. The user of the transport layer > > passes the client transport the request, an IP address, port, > > transport, and possibly TTL for multicast destinations. > > I > > f 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. > > > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
