Hi Martin, I'm not sure, but I think IP fragmentation and TCP segmentation are two different things. In most cases you only get TCP segmentation and it doesn't use the "more-fragments" flag.
IP fragmentation happens if the sender doesn't know the MTU and it sends a packet that is too big, and then the network layer must divide the packet into fragments. I think it should not happen on typical ethernet-only network. It would mean that your packets are correct and the problem is at your gateway. TCP is a "stream" protocol by nature. It means that the data sent over network is logically treated as a continuous stream of bytes, not as a sequence of packets. So, there is no information on TCP level telling you if there will be more segments. To detect if you received whole message, you must use information from higher layer protocol (in this case SIP). In SIP, the end of message should be detected as follows: - first, receive until end of header (empty line) - then, if content-length was > 0, receive message body, which as many bytes as content-length. The end of message is after receiving the whole body (whose length is specified by Content-Length header). That's why the Content-Length header is necessary - it's purpose is to tell where the message ends. Best regards Tomasz Radziszewski > hi all, > > I do not know if in this thread is allowed to talk about openser, but in my > work we're facing a problem that I'd like to share with you and maybe you > can help me. > > We are having some problems with long SIP IP packets that are being > fragmented. > > We are using TCP as transport and packets bigger than ethernet MTU (1500) > are being fragmented, but the "more-fragments" bit in IP flags is not being > set. > > This is causing the remote gateway to timeout and close TCP session. > > Have somebody come across this issue before? Any suggestions? > > Thanks ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://sourceforge.net/services/buy/index.php _______________________________________________ Sipp-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/sipp-users
