Cisco 7821 SIP over TCP only?

[andrew011]

Does the Cisco 7821 only support SIP over TCP? 

[Terry Cheema]

No it supports SIP over both TCP and UDP. You can choose TCP/UDP/TCP+UDP in non-secure mode.

There are two components here: Connection + Actual RTP payload. We are talking about the connection here to CUCM. For this you can use SIP over either TCP or UDP but actual RTP audio will always be run over the UDP.

The Cisco SCCP only runs over TCP.

I hope its clear.

-Terry

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[andrew011]

Thank you Terry. I'm only concerned about the SIP signaling not the RTP audio. Do you know the XML parameter that controls the transport type in the configuration file?

Actually I found the parameter <transportLayerProtocol> it was set to 4 which is to prefer the default transport protocol which in the case of the 7921 is TCP. I've switched the value to 2 in order to prefer UDP.

[Terry Cheema · Accepted solution]

Are you using Astresik? Anyways check the below parameter:

<transportLayerProtocol>2</transportLayerProtocol>

The number highlighted in blue represents the protocol you want to use:

1 = TCP

2 = UDP

4 = TCP+UDP (This is the default setting)

Hope that helps.

-Terry

Please rate all helpful posts and mark the thread as answered if you have no other queries.

[Terry Cheema]

Yeah that's correct. I confirmed this with the wireshark pcap, when set to 2 it changes to UDP.

Anyways please mark the thread as answered if you have no other queries.

-Terry