SRST Support for Grandstream SIP phones

[pernestoquevedo]

Hello,

I need to configure CUCM with SRST on branches but we have only Grandstream phones in some of the branches. Will a router with SRST be able to pick up such phones when the CUCM WAN connection fails? I cannot find explicit support for third party phones on the Cisco Documentation.

Granstream devices use RFC 3261

http://www.grandstream.com/support/faq/common-questions/common-configuration-questions

And SIP SRST Cisco does support the same RFC 3261.

https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cusrst/admin/sccp_sip_srst/configuration/guide/SCCP_and_SIP_SRST_Admin_Guide/srst_overview.html

[Mohammed al Baqari]

I don't think this will work. SRST GW IP is provided to phones using TFTP file from CUCM. I don't think that grandstream or 3rd party phones will download tftp from CUCM. They use digest authentication for registration and getting the DN.

[pernestoquevedo]

Thank you for your answer. I do think by setting a second SIP server on the phones this might work. Assuming that they have the configuration file already. They already work with a CME as I understand so I would assume it also works with CUCM. Are these assumption incorrect?

Thank you again

[Ayodeji Okanlawon]

If you can set multiple sip registrar servers on the phones then it should work. The question is does the phone has the ability to know which server is active and which is on stand by. If it does then once the active server is unreachable then it should attempt to register to the stand by server.