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Polycom phone not playing Music On Hold in a HA scenario

Occasional Advisor

Polycom phone not playing Music On Hold in a HA scenario


We are trying to find a fix for the following problem;maybe you could help us with some information.

We have a high availability setup made up of 3 SIP servers.

The high availability design is based on the DNS service running on each server.

One of the servers is primary,and the other two are secondary.
We have two Polycom VVX600 initially registered to the primary server.
We want to test what happens when the primary server is lost,and one of the other servers has to provide the needed services,for example music on hold (MOH).
We shut down the primary server,and after a while the Polycom phones will re-register with one of the secondary servers.
After registering,the Polycom phones can place/receive calls successfully.
The problem we found,is with MOH.
When ,in a call, let's say Polycom 1 will place Polycom 2 on hold.
When this happens,the respective secondary server will query the DNS service to find out available MOH servers.
Possible servers are found by DNS,and then the list/answer is sent to the secondary server.
The secondary server starts contacting the MOH servers in the order received.
If the first server contacted is down,he will try the next one.
While this process takes place,the Polycom phone will timeout and Cancel the INVITE  - as a result music on hold will not play.

So the question is : can we tweak the Polycom phone config in such a way that it will allow more time before timing out?

I attached a capture for the above issue.

Here are the capture details:

1. Primary
2. Secondary
3. 3rd Server
Shutdown Primary server.
Steps :
1.200 call 201 and 201 answers. Result : there is voice path.
2.200 places 201 on hold. Result : 201 hears moh.
3.200 resumes the call. Result : there is voice path
3.201 places 200 on hold
Reported problem : 200 will not hear moh.

Additional steps :
4.201 unholds call. Result : there is voice path
5.201 ends call.