Specifications

Setting Up the Network
How to Set Up the Network
42
Cisco IOS Survivable Remote Site Telephony Version 3.4 System Administrator Guide
Verifying That Cisco SRST Is Enabled
To verify that the Cisco SRST feature is enabled, perform the following steps:
Step 1 Enter the show running-config command to verify the configuration.
Step 2 Enter the show call-manager-fallback all command to verify that the Cisco SRST feature is enabled.
Step 3 Use the Settings display on the Cisco IP phones in your network to verify that the default router IP
address on the phones matches the IP address of the Cisco SRST router.
Step 4 To temporarily block the TCP port 2000 Skinny Client Control Protocol (SCCP) connection for one of
the Cisco IP phones in order to force the Cisco IP phone to lose its connection to the Cisco CallManager
and register with the Cisco SRST router, perform the following steps:
a. Use the appropriate IP access-list command to temporarily disconnect a Cisco IP phone from the
Cisco CallManager.
During a WAN connection failure, when Cisco SRST is enabled, Cisco IP phones display a message
informing you that they are operating in Cisco CallManager fallback mode. The Cisco IP
Phone 7960 and Cisco IP Phone 7940 display a “CM Fallback Service Operating” message, and the
Cisco IP Phone 7910 displays a “CM Fallback Service” message when operating in
Cisco CallManager fallback mode. When the Cisco CallManager is restored, the message goes away
and full Cisco IP phone functionality is restored.
Step 4
max-ephones max-phones
Example:
Router(config-cm-fallback)# max-ephones 24
Configures the maximum number of Cisco IP phones
that can be supported by the router. The default is 0. The
maximum number is platform dependent. See the
“Platform and Memory Support” section on page 24 for
further details.
Note You must reboot the router in order to reduce the
limit of Cisco IP phones after the maximum
allowable number is configured.
Step 5
limit-dn {7910 | 7935 | 7940 | 7960} max-lines
Example:
Router(config-cm-fallback)# limit-dn 7910 2
Limits the directory number lines on Cisco IP phones
during Cisco CallManager fallback.
Note You must configure this command during initial
Cisco SRST router configuration, before any
phone actually registers with the Cisco SRST
router. However, you can modify the number of
lines at a later time.
The setting for maximum lines is from 1 to 6. The default
number of maximum directory lines is set to 6. If there is
any active phone with the last line number greater than
this limit, warning information is displayed for phone
reset.
Step 6
exit
Example:
Router(config-cm-fallback)# exit
Exits call-manager-fallback configuration mode.
Command or Action Purpose