Problem in SRST configurations

[dsobrinho]

Hi

First of all, sorry for my English.

We have the following situation. Our customer had a site with a predefined network for IP phones and a survival setting (SRST). We had ve a cluster of CUCM version 11.5 in datacenter (hostlocation company) and VPN to connect the Branchs sites.

Currently, them office in São Paulo city,  has grown since joining other company, which in turn also has its own voice network and SRST gateway.

The networks were divided and segmented by floor. Both are connected in the same CUCM Cluster but, with different Extensions number and PSTN, as well as SRST Gateways. 

We noticed that some phones were no longer entering SRST mode when have fail connection with Cluster of CUCM in Datacenter. There are few phones have this anomaly.

And we realized that the ip phones they were on another floor, in another network. We would like to know if this logs prove this problem and we appreciate if you can point out some solution to the problem.

Configuration in SRST Gateway:

voice register pool  1

 id network 10.4.196.0 mask 255.255.252.0----> This is the local Voice Network for IP Phones

 proxy 10.y.196.90 preference 2 monitor probe icmp-ping ----> This is PUB CUCM in the Cluster

 presence call-list

 voice-class codec 1

Logs of error:

Aug 13 19:03:58.444: VOICE_REG_POOL: Register request for (4364) from (10.7.4.163) <<<  Endereço IP do SIP Phone Mac Address: 2C3E.CF87.D0A0

Aug 13 19:03:58.444: VOICE_REG_POOL: Contact doesn't match any pools

Aug 13 19:03:58.444: VOICE_REG_POOL: No entry for (4364) found in contact table

Aug 13 19:04:05.976: voice_reg_get_reg_expires_timer: no voice register pool found

Note that IP Phone with extension 4363 is in the network 10.7.4.0/24 although the device belongs to the device pool that points to the SRST Gateway from network  10.4.196.0. I belive that is the problem.

The device is located in another network, when connection to cluster of CUCM fails the device did not found register in SRST Gateway because is in different network.

[Sreekanth Narayanan]

Daniel, the register requests should come in from the same network as configured in the voice register pool. The register request in the above log snippet is arriving from 10.7.4.163 while the voice register pool network is configured for 10.4.196.0 mask 255.255.252.0. So this registration will fail.
You need to change the phones' device pools to point to the SRST router that's located in the corresponding network as the phones.

[dsobrinho]

Hi @Sreekanth Narayanan,

Can we use a secound voice register pool to match the phones that is in different network?

[Sreekanth Narayanan]

Yes, you can do this. voice register pool 2 can be created for the other network of phones.

[R0g22]

First thing, no need for the proxy under the pool. Second, the id network would be actual subnet where your phones reside. It might be a subset of your actual voice network though. Third, ensure that your SIP bindings are correct. Fourth, if this router is a CUBE, SIP SRST is not supported on ISR-G2 and only support starting XE code Fuji on ISR-4k.