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.
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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
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.
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