Nortel Networks NN43001-563 - Manual (Page 420)

420 Maintenance
Remove the card for two to three seconds and then re-seat it in the IPE
shelf. If the failure continues, replace the card.
DCH failure
There are three types of DCH failure which can affect the IP trunk card:
1. DCH link failure (DCH releases)
2. PC Card failure
3. DCH card failure
When the DCH fails (with no backup DCH), the following occurs:
• Established calls are maintained.
• Transient calls are dropped.
• No new incoming calls are assigned to trunks associated with that DCH.
• Outgoing calls are blocked from occurring by the associated Follower
cards forcing their trunks to a busy state.
• When the far-end user releases an established call, the system uses
SSD messaging to the system to inform the core the call is released.
• When the near-end user releases an established call, the system
informs the Follower through SSD messages.
• ISDN features across the IP network do not work.
DCH link failure
The DCH link can change to the RLS (Release) state due to technician
action in LD 96, MSDL or SDI/DCH card failure, or cable failure. This
condition is detected on the DCHIP card by the PC Card signaling that
the L2 connection has failed.
PC Card failure
The PC Card failure can be detected in various ways, such as the following:
• missing heartbeat transmission
• a hardware interrupt
When the software does not send "an activity test message" (heartbeat
message) to the Card Services of the PC Card Device Driver during a period
greater than n seconds, Card Services consider it a breakdown detection.
Card Services tries to reset the PC Card. Card Services are responsible
to ensure the conformance of the reset timing. Card Services also check
and wait for the card to reach the READY state.
Nortel Communication Server 1000
IP Trunk Fundamentals
NN43001-563 01.01 Standard
Release 5.0 30 May 2007
Copyright © 2007, Nortel Networks
.