SRST configuration

[geeta.kumari1]

Hi All,

I want to understand that below SRST configuration will work properly. I have a doubt on this -

In CUCM srst reference is given as Loopback IP address of router at port 2000. SRST Reference>>>Loopback Interface-172.29.254.8

In router under call-manager-fallback, the source-address is given as Lan interface 172.28.23.1

call-manager-fallback
secondary-dialtone 9
max-conferences 3 gain -6
timeouts interdigit 5
ip source-address 172.28.23.1 port 2000
max-ephones 73
max-dn 146
time-format 24

[Siva chinap]

The reference address and Source address should be same.

[geeta.kumari1]

Thanks Siva for prompt reply.

[Jaime Valencia]

Phones will look at 172.29.254.8 to send the registration and keepalives, if the ISR doesn't have that IP configured, or that's not the IP where you're binding the SRST process to listen to them it will not work, just as if you configure an H.323 GW and configure one IP in CUCM and bind the signaling to other one.

[geeta.kumari1]

Thanks Java :)

I will try to test this as soon as possible and share my observation.

[Jonathan Schulenberg]

Siva js correct, they should match.

CUCM Reference Address is the IPv4 address that the phone is told to fallback to in the XML config file CUCM builds for it. The IOS source-address is the IPv4 address that IOS sources packets from. Your config example is missing the "strict-match" keyword at the end of the "ip source-address" though so this behavior will be sloppy and may actually allow the phone to register.

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cusrst/command/reference/srstcr/srsa_a_m.html#wp3231109180

[geeta.kumari1]

Hi Jonathan,

Thanks for reply. Generaly I keep the srst reference IP address in cucm and ip source address same. But i have come across one config where it differs.

As u said i believe that there is possibility that it can allow phone to register. I was trying to relate with one of my experiences where in mgcp gateway the bind interface in gateway is different and in cucm the gateway ip address shows of lan interface and calls were working fine. As per cisco recommendation we change them bind interface later.

PLS correct me if im thinking wrong.