Information Technology Reference
In-Depth Information
The
call-manager-fallback
command is used to enable SRST and enter call-manager-fallback configuration mode.
The
ip source-address
ip-address
port
port
[
any-match
] [
strict-match
] command configures the router to receive (SCCP) messages
on the specified IP address, using the specified port. In the example, the router is configured to receive messages on IP address
10.1.1.1 using the default port of 2000. The
any-match
keyword (the default) disables strict IP address checking for registration, and
the
strict-match
keyword enables strict IP address checking.
Next,
max-ephones
max-phones
is used to specify the maximum number of Cisco IP phones (ephones) that can be supported by the
router.
The
max-dn
max-directory-numbers
command is used to configure the maximum number of directory numbers (DN) supported by
the router.
Another command that is optional but can be useful is
limit-dn
{
7910
|
7935
|
7940
|
7960
}
max-lines
. This command can limit the
number of directory number lines on Cisco IP phones during SRST fallback. This can be useful if an SRST router cannot support all
the multiline phones at a remote location, and you instead want to limit each phone to a certain (smaller than usual) number of lines.
An SRST reference must also be configured on CUCM for SRST to operate correctly. If the SRST router is the default gateway for
remote site phones, it is possible to specify the default gateway as the SRST reference in the device pool (
System, Device Pool
).
If the SRST router is not the default gateway, the SRST reference must be configured by navigating to
System
,
SRST
under Cisco
CUCM Administration.
Note that if you are configuring SRST on an MGCP gateway, the
call-manager fallback-mgcp
and
service
[
alternate
|
default
]
commands are necessary to enable the fallback feature and ensure that the MGCP gateway can provide call processing with SRST or
other configured applications, and to load and configure a specific standalone application on a dial peer.
It is also possible to configure DHCP on the SRST router using the
ip dhcp pool
,
network
,
option 150 ip
, and
default-router
commands to configure the DHCP pool name, pool address, DHCP option 150 (TFTP server address for phone image download), and
the default router address, respectively.
Some useful commands to verify the correct operation of SRST are as follows:
■
debug ephone register:
Displays the Cisco IP phone registration process in operation.
■
debug ephone keepalive:
Displays keepalive debugging for Cisco IP phones.
