Nortel Networks NN43001-563 DCH failure, DCH link failure, PC Card failure

422 Maintenance
Remove the card fortwo 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.
•Transientcalls are dropped.
•No new incoming calls are assigned to trunks associated with that DCH.
•Outgoing calls are blocked from occurring bythe 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 callis 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 cablefailure. This
condition is detected on the DCHIP card by the PC Cardsignaling 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 Driverdur ing a period
greater than n seconds, Card Services consider it a breakdown detection.
Card Services tries to reset the PC Card. Card Ser vices are responsible
to ensure the conformance of the reset timing. Card Services also check
and wait for the card to reach the READYstate.
Nortel Communication Server 1000
IP TrunkFundamentals
NN43001-563 02.01 Standard
Release 5.5 21 December 2007
Copyright© 2007, Nor tel Networks
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