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SIP dialling URI Issues

Hi All,

I have a question on SIP dialling URI

When dialling a URI to external SIP address , why it takes a long time to connect ? and Sometimes it doesn't even connect.

But it works fine with internal SIP dial.

1)Please can you tell me all the reaasons which causing this delay in addressing.?

2)Reasons for not able to connect to external SIP address?

3)How it can be resolved or what are the steps to reslove the same?any settings in VCS?




SIP dialling URI Issues

1) It takes a "long" time because you have UDP enabled - disable this and you'll find connection time gets radically shortened.

2) Incorrect address, no SRV records in place at external site, client/end-point not registered with a SIP registrar, system not configured for auto-answer. The VCS log should give you an idea.

3) Disable UDP on VCS-E (VCS Configuration/Protocols/SIP/Configuration).

Have you got a DNS zone configured on VCS-E and an appropriate search rule pointing to it?

To bypass DNS you can try replacing domain with IP address in the external address, i.e. instead of try Alias@IP_address_of_external_SIP_registrar.


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SIP dialling URI Issues

What Jens mentioned is correct.

It can also be caused by firewall trouble and sure issues at the remote site as well or some other


If asking such questions it is always handy to tell us a little bit more about your setup,

which components are involved, which version numbers are used, what is exactly dialed,

whats the call flow, what do you see in the logs.

In most cases disabling sip/udp on the vcs-e is the answer and its even disabled in

newer default configurations of the vcs. Anyhow, you should check if you need sip/udp

for any kind of external integration or call scenarios first, especially telephony integrations

might use udp.

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