SRST in Remote & CCME Main

[jvelasquez]

Hello everybody,

I have this topology:

REMOTE: (01) C2801 + 2FXO -10users

MAIN : (01) CCME V.7.1 for 100 Users

Is it possible to configure SRST in the remote site as contingence if the CCME fails or the WAN is down?

I know it isn't common this situation , but i want to know if SRST works in that case.

Thanks for any comment.

José Luis

[jcaro]

Hello Jose,

CCME basically evolved from SRST. When Cisco realized that a single router could run a SRST office, they developed CCME based on the same technology with many additional features.

CCME and SRST do the same thing; just that CCME is doing it all the time, whereas SRST is a backup for CCM.

If the WAN failed, and it was sending calls out to a call manager via voip dialpeer, then those calls would get fast busy. The CME would then use

dial-peers to find an alternate route out the PSTN via FXO or PRI.

If CCME is down hard then you are out of luck.

The Cisco SRS Telephony Software operates by taking advantage of the keepalive packets emanating from the centralized Cisco CallManager cluster and local Cisco IP Phones.

CCME has not ability to send the keepalives.

[jvelasquez]

Hi Jaime,

Thanks for your comment. I tried to mean this scenario:

REMOTE: IP Phones + C2801( WAN)

MAIN: CCME (WAN)

Where, C2801 only allows access to WAN and the remote IP Phones are registered into CCME. There is not any Cisco CallManger(like CUCM v6,7)

In this scenario, is it possible to configure SRST in C2801 as a backup for CCME?

According your last comment: "CCME has not ability to send the keepalives", SRST doesn't work here. Can you confirm this.

Thanks.

José Luis

[paolo bevilacqua]

If CCME is down hard then you are out of luck.

The Cisco SRS Telephony Software operates by taking advantage of the keepalive packets emanating from the centralized Cisco CallManager cluster and local Cisco IP Phones.

CCME has not ability to send the keepalives.

That is not correct. Since quite some time already, CCME support redundancy to a secondary router, based exactly on SCCP keepalives.