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Cisco BTS 10200 Softswitch Troubleshooting Guide, Release 5.0.x
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Chapter 15 Diagnostic Tests
PSTN Trunk Testing
PSTN Trunk Testing
The legacy PSTN trunk network supports connection and performance appraisal testing individual
trunks or network routes. This is generally referred to as 100-type tests. The Cisco BTS 10200 provides
specific capabilities to support test call origination to selected individual trunks as well as test call
termination.
Test Overview
Trunk testing is used to ascertain the transmission quality of the shared trunks used to interconnect
switching systems. This is necessary because there is no other practical way to objectively determine
each trunk’s performance.
depicts a typical trunk test system.
Figure 15-3
Typical Trunk Test System
The test controller is located on the originating side of the trunk test system. The controller selects a
trunk group and a specific trunk within the trunk group to test. It then instructs the near end test
equipment, which is connected to the OTL and switch to select the specified trunk and the destination
number for the far end test set.
The near end switch then selects the Trunk Under Test (TUT) and, if the TUT is idle, dials the destination
number through CAS or nonassociated signaling methods common to normal signaling for the trunk
group. If the TUT is busy, an announcement is returned (usually reorder) towards the near end test set
and the test call does not proceed.
The far end switch responds to the dialed digits by connecting to the far end test set via the TTL. The far
end test set answers the call request. The near end and far end test equipment then conduct the required
tests. The results are retrieved by the Test Controller.
Near End
Switch
Far End
Switch
Trunk Group
Trunk Under Test
Test
Set
Test
Set
OTL
TTL
Test
Controller
Control
Link
Selection Link
(Optional)
Near End
Switch
Far End
Switch
Trunk Group
Trunk Under Test
Test
Set
Test
Set
OTL
TTL
Test
Controller
Control
Link
Selection Link
(Optional)
