4 Replies Latest reply on May 31, 2013 7:58 AM by david

    SIP over TCP - Any hope to get implemented?

    jayh Hall_of_Fame

      We have a number of cases where SIP over TCP is needed.  Busy lamp fields where UDP fragmentation is a big issue, traversing firewalls not under our control with short UDP timeouts work fine with TCP, etc.  Adtran themselves use SIP over TCP on these devices for N-Command VQM monitoring.


      It is in the CLI configuration of the TA900 and has been for some time.


      ip sip

      ip sip tcp


      It is in the SIP specification RFC 2543 dated March 1999.


      The problem?  It doesn't work, and never has. 


      Adtran TA900 devices (and Netvanta 3120) simply don't recognize TCP5060 datagrams as SIP messages for proxy or ALG.


      Adtran support doesn't consider this to be a bug or failure, but an "enhanced feature request" (despite it being in the March 1999 RFC), and punts this lack of functionality to our sales rep.  Requests there seem to fall into a black hole.  It has been over two years since we first asked. 


      Does anyone from Adtran reading this forum have the horsepower to get this fixed?  Are we alone in needing it? 

        • Re: SIP over TCP - Any hope to get implemented?



          We support SIP over TCP everywhere in AOS except for the SIP ALG and the SIP proxy’s transparent mode. Stateful mode and outbound proxy mode do support SIP over TCP.


          We did recently add full support for TCP/UDP Inter-working for SIP Trunking applications where the B2BUA is involved. If you are trying to use us an SBC/Proxy for a SIP PBX that supports TCP, then this would be the way to go. It was added in R10.3.0.




            • Re: SIP over TCP - Any hope to get implemented?
              jessiebryan New Member

              I've been waiting *years* for this as well.  It's frustrating that the feature remains on the "Things we need to do someday, but probably won't." list


              I'm also surprised Adtran hasn't removed the "ip sip tcp" command set, since it doesn't work (and is documented as such in the AOS Voice Errata).



              Frustrated AOS User

              1 of 1 people found this helpful
              • Re: SIP over TCP - Any hope to get implemented?
                jayh Hall_of_Fame

                Thanks, Rob.  The vast majority of the places it is needed are proxy environments where the phone has busy lamp field appearances requiring fragmenting the SIP datagram.  SIP UDP fragmentation is iffy at best.  I'm hoping to move it a bit higher on the radar as more and more of the modern phones requiring SIP proxy have multiple BLF appearances.  UDP through firewalls and some carrier gear is also occasionally an issue being connectionless.


                Any help on getting TCP implemented would be greatly appreciated.

              • Re: SIP over TCP - Any hope to get implemented?
                david Employee



                I went ahead and flagged the "Correct Answer" on this post to make it more visible and help other members of the community find solutions more easily. If you don't feel like the answer I marked was correct, feel free to come back to this post and unmark it and select another in its place with the applicable buttons.