Chapter 6 Conversions And Transparency; Q.931/Dpnss Conversion Configuration; Q.931 Port 1 Configuration; Basic Configuration - Cisco VG30D User Manual

Conversions and Transparency

Q.931/DPNSS Conversion Configuration

Q.931 Port 1 Configuration

Basic Configuration

The default setting of the Q.931 port at Layer 2 (Q.921) specifies USER End. You must configure this
with inverse orientation to the attached equipment/network.
As the default, the Cisco VG30D Voice Gateway causes a Layer 2 RESET on recovery after physical
layer failures. This causes all calls to be cleared when a Channel 0 fault is notified. Alternatively, you
can configure the Cisco VG30D Voice Gateway to ignore Layer 1 fault indications and rely on periodic
Layer 2 status polling to detect link problems.
Protocol Orientation
The Layer 3 orientation gets set automatically according to the profile and Layer 2 orientation.
Action on Link Layer RESET
As the default, the Cisco VG30D Voice Gateway takes action to validate Q.931 call status for all fully
active calls on notification of a Link Layer RESET. Calls only get cleared if they are not fully set up or
a discrepancy exists in call state.
You can configure this to cause all calls to be cleared when a Layer 2 fault is notified, regardless of their
state. If the glitch sensitivity has been reduced in Channel 0 configuration, you may want to clear calls
after a fault is finally notified. Status validation should be adequate in most cases.
Overlap Signalling Support
If the Q.931 network/equipment supports overlap signalling, enable it by selecting Incoming for overlap
from Q.931, Outgoing for overlap towards Q.931, or Both Ways.
For transparent signalling, set overlap signalling to Both Ways.
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