SIP Over TCP vs. UDP


Office Communications Server 2007 (and the coming R2) is based on a SIP stack that supports TLS (using TCP as the base transport) by default.  OCS 2007 does not support UDP.  I’ve had discussions with developers about this engineering choice.

When the subject comes up, I often mention this post on comparing TCP and UDP from the Office Communications Server team.


Comments (2)

  1. Joel Peterson says:

    Thanks again for providing this link in our post-Metro emails, at the time I had forgotten about it when my team was discussing the merits of TCP and UDP. Hopefully this will just result in the original post being the first item in a web search.

    Take care, Chris.

  2. Simon Booth says:

    Regardless of the debate, making it work is relatively easy because OCS has the media translation built into the mediation server for G711 over UDP – there are posts out there on using SER or asterisk on linux to accomplish this – in fact thats what the officially supported ITSP’s are doing on their end.

    We have a windows based product in beta right now that enables SIP registration from OCS to any ITSP (UDP or TCP) and because it uses sip registrations it also allows for flexibility in terms of firewall configurations and NAT.

    Prior to building this we used a soft pbx (PBXnSip) to achieve the same thing.