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Cisco BTS 10200 Softswitch ISDN Provisioning and Troubleshooting
OL-12436-02
Chapter 4 Maintaining and Troubleshooting the ISDN System
How to Troubleshoot When the ISDN D-Channel Fails to Restore
Step 3
D-channel states for FAS:
ISDN D-Channel restore establish fail normal or switchover
or NFAS:
ISDN
D-Channel sent Establish Request
.
This means the specific ISDN D-channel could not be restored. This is likely related to ISDN layer1 or
layer2 not being up, or related to DCHAN-SLOT and DCHAN-PORT in the ISDN D Channel table. The
media gateway and Call Agent are communicating successfully (session came up).
Things to Check:
a.
On the media gateway, enter a
show isdn status command
. Is Layer 1 shown as ACTIVE? If not,
there may be a cable problem, or the PBX is down.
b.
Does the
show isdn status
command return a
Network side configuration
? The PBX should be set
up for the user side. The gateway should be setup for the network side.
c.
Was the media gateway reloaded (rebooted) after setting up parameters? There can be problems
when this has not been done. This is usually reflected by having two TEI values for the T1.
d.
Are the DCHAN-SLOT and DCHAN-PORT provisioned correctly in the IDSN D Channel table?
e.
Does the T1 on the media gateway show an alarm (red or yellow lights)? These are more clues that
there is an ISDN layer1 or layer2 problem.
f.
Is the controller T1, or interface Serialn:23, provisioned correctly on the gateway?
g.
Look at the trace.log on the Call Agent. Search for BSM_dchan_tbl_insert or bsm_dchan_tbl_insert.
The slot-port value is the actual value retrieved from the database. For the AS5300, this value should
be 0, 1, 2, or 3. This is a decimal value. The top 16 bits are the slot and the bottom 16 bits are the port.
Step 4
D-channel states for NFAS:
ISDN D-Channel is in Wait for Service Ack
or
ISDN D-Channel is
Maintenance Busy.
This means the states at the far end are going to send a SERVICE_ACK to the Cisco BTS 10200
Softswitch service message for PRI.
Things to Check:
Make sure the far end is sending a SERVICE_ACK. There are some other D-channel states that happen
after the ISDN backhaul is successfully established.
Step 5
Trunk group states for FAS:
ISDN D-Channel down session set fail hard normal
or NFAS:
ISDN
D-Channel is Backhaul Session Down.
This is the same as
ISDN D-Channel restore session set fail normal
or
ISDN D-Channel is Backhaul
Session Down.
However, in this case, the backhaul session was already successfully established, and
then went out. This likely means that the Call Agent and media gateway have lost IP connectivity. Or,
the media gateway has lost power. This can also happen if the provisioning was changed, particularly the
session settings in the media gateway.
Step 6
D-channel states for FAS:
ISDN D-Channel down establish fail hard normal
or NFAS:
ISDN D-Channel
sent Establish Request.
This is the same as ISDN
D-Channel restore establish fail normal
or
ISDN D-Channel sent Establish
Request
. However, in this case, the D channel was already successfully established, and then went out.
Things to Check:
a.
Is, or was, the cable unplugged between the PBX and the gateway?
b.
Was the provisioning changed on the gateway?
