ciscofreak1241
MIS
I have a strange issue here that I believe could be a Service Provider problem. This could be an ISDN question, but any input and help on this will be great. This is in regards to a branch router with SRST and MGCP with H.323 fallback enabled.
When there is a WAN failure at the branch office I can make and recieve calls from all IP Phones in the remote office. Great, so everything works.
When the WAN is restored everything returns to normal. However, if the WAN fails again in time the remote site will go back to SRST mode, which we know. But this time if I try to place a call or recieve a call I get a fast busy right away. Heck, I have enabled "debug voice dialpeer" and "debug isdn q921" to see what is going on. I see nothing as if it never reached the gateway rtr. I have to shutdown the T1 PRI interface and bring it backup. At that point I can place calls again. ;(
This happens for every other failover ... every time. Looking at the logs I think I have determined the issue.
Under normal operation I do a "show isdn status":
Layer 2 Status:
TEI = 0, Ces = 1, SAPI = 0, State = MULTIPLE_FRAME_ESTABLISHED
However, when I the issue occurs and recieve the fast busy, I see the following under "show isdn status":
Layer 2 Status:
TEI = 0, Ces = 1, SAPI = 0, State = TEI_ASSIGNED
Apparently the ISDN PRI Layer 2 is not coming up when it says TEI_ASSIGNED (TEI 0 is down).
What are some of the common problems for something like this? Is this a possible problem with the PSTN switch with our provider? Maybe there is some additional configuration I can do to force Layer-2 to be established.
Any help on this would be great or advice on what configuration is needed or that it could be a problem with the PSTN provider (in regards to the communication between our voice gateway and the PSTN switch in the cloud).
Thanks in advanvced!
ciscofreak
When there is a WAN failure at the branch office I can make and recieve calls from all IP Phones in the remote office. Great, so everything works.
When the WAN is restored everything returns to normal. However, if the WAN fails again in time the remote site will go back to SRST mode, which we know. But this time if I try to place a call or recieve a call I get a fast busy right away. Heck, I have enabled "debug voice dialpeer" and "debug isdn q921" to see what is going on. I see nothing as if it never reached the gateway rtr. I have to shutdown the T1 PRI interface and bring it backup. At that point I can place calls again. ;(
This happens for every other failover ... every time. Looking at the logs I think I have determined the issue.
Under normal operation I do a "show isdn status":
Layer 2 Status:
TEI = 0, Ces = 1, SAPI = 0, State = MULTIPLE_FRAME_ESTABLISHED
However, when I the issue occurs and recieve the fast busy, I see the following under "show isdn status":
Layer 2 Status:
TEI = 0, Ces = 1, SAPI = 0, State = TEI_ASSIGNED
Apparently the ISDN PRI Layer 2 is not coming up when it says TEI_ASSIGNED (TEI 0 is down).
What are some of the common problems for something like this? Is this a possible problem with the PSTN switch with our provider? Maybe there is some additional configuration I can do to force Layer-2 to be established.
Any help on this would be great or advice on what configuration is needed or that it could be a problem with the PSTN provider (in regards to the communication between our voice gateway and the PSTN switch in the cloud).
Thanks in advanvced!
ciscofreak
