Troubleshooting guide

Voice Networking
161
T1/E1 Trunk Resiliency
Table 55: Troubleshooting T1/E1 Trunk Resiliency
Symptoms Possible Cause Corrective Action
Users cannot make T1/E1
calls through T1/E1 MMC
modules in the primary or
secondary controllers.
Links are connected in reverse:
You have programmed T1/E1 trunk
resiliency correctly, but the physical
connections are reversed. The Input
port on the secondary controller is
connected to the PSTN and the
Failover port on the secondary is
connected to the main port on the
primary.
Reverse the connections. See
“Configuring T1/E1 Trunk Resiliency” in
the MCD Resiliency Guidelines for a
configuration diagram.
The physical connections are
correct and the primary
controller is out of service, but
users cannot make T1/E1
calls through the T1/E1 MMC
on the secondary controller.
Secondary is not programmed as
resilient:
In the Digital Links form of the
secondary controller, the Resiliency
Link box is not checked, or you have
not programmed the “Primary
System Name” and “Secondary
System Name”.
In the Digital Links form of the secondary
controller:
• Select the T1/E1 link and click
Change. Check the “Resilient Link”
box.
• From the Resilient Link ID drop-down
menu, select a link identifier (1 to 4) for
the secondary link. This link ID must
match with the link ID that you
assigned to the primary link.
• Set the Primary System Name to the
system name of the primary controller.
• Set the “Secondary System Name” to
the name of the secondary (Local)
controller.
The physical connections are
correct. However, alarms for
the Trunk Alarm category on
the secondary controller are
exceeding the threshold limit.
In addition, if the primary
controller is out of service,
users cannot make T1/E1
calls through the T1/E1 MMC
on the secondary controller.
Both links are designated as
primary controller:
In the Digital Link Assignment forms
of both controllers, the “Primary
System Name” is set to the name of
the Local controller.
When the primary controller
is out of service, the T1/E1
trunks are not transferred to
the secondary controller. No
alarms are generated.
Both links are designated as
secondary controller:
In the Digital Link Assignment forms
of both controllers, the “Primary
System Name” is set to the name of
the other controller. Both controllers
have their own system name
selected as the “Secondary System
Name”.
Correct the T1/E1 trunk resiliency
programming in the Digital Link
Assignment forms of both systems. Refer
to.the MCD Resiliency Guidelines for
T1/E1 trunk resiliency programming.
The primary controller fails
over to the secondary but
users are unable to make
calls through the resilient
T1/E1 MMC in the secondary
controller. When the user
attempts to make an outgoing
call, the system is unable to
seize the T1/E1 trunk.
Route List Assignment form is
programmed incorrectly. The
route list programming on either the
primary or secondary controller is
reversed.
Correct the route list programming. Refer
to the MCD Resiliency Guidelines for
T1/E1 trunk resiliency programming.