Configuring Call Watch - HP FlexNetwork MSR Series Configuration Manual

Configuring call watch

The call watch function is only applicable to voice E1/T1 interfaces. The E1/T1 interfaces mentioned
in this document are all voice interfaces.
Overview
Call watch enables a voice device to decide whether an E1/T1 interface is available for setting up
calls for a callee by monitoring the state of the local interface or the IP connectivity to the remote
interface connected to the callee.
Figure 85 Network diagram
Voice device
Local link
VoIP network
As shown in
and through an E1 or T1 link to the PBX to which user A is attached. This provides VoIP
communication between the two users in normal cases. When the local link is detected as
unavailable, the voice device sets the E1/T1 interface to watch-out state, disabling the interface to
respond to calls from the PBX. Detecting that the E1/T1 link is unavailable, the PBX switches to the
backup link to forward calls from user A to user B. When the local link recovers, the watch-out state of
the E1/T1 interface is removed and the PBX can thus dial through the E1/T1 link. As a result, calls
from user A to user B are set up across the local link.
Call watch concepts
Call watch group
The call watch function is implemented through call watch groups, each monitoring the state of one
or multiple local links.
Monitoring rule
A call watch group is a set of monitoring rules each defining a local interface or remote IP address
monitored by the group.
A call watch group can monitor either local interfaces or remote IP addresses (that is, IP connectivity
to remote interfaces), but not both.
The state of the E1/T1 interface associated with a call watch group is set as follows:
E1/T1
Backup link
Backup
network
User B
Figure 85, a call watch-enabled voice device is connected through a local link to user B
PBX
User A
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