Scenario
Device: Cisco Voice Gateway
Telecom: ISDN Line
Description: What does it mean when Voice Gateways show ISDN status as TEI_ASSIGNED or How to check the ISDN status on Voice Gateway when we have issues of inbound/outbound calling?
Many organizations use in-house voice gateway. As the name suggests is the gateway for voice. There are many Cisco routers available that can work as a voice gateway. Generally, the PRI or ISDN lines get connected to the voice gateway. Like other devices, we get issues in the Voice gateway as well. “TEI_Assigned” is one of the statuses of voice gateway which is actually an issue.
If the ISDN status on Voice Gateway is “TEI_ASSIGNED” it shows the ISDN connection is not established with the Voice gateway. This could be because of the issue at ISP/Telecom company end or the card/cable is faulty.
edledge-vg#sh isdn status
Global ISDN Switchtype = primary-net5
ISDN Serial0/0/0:15 interface
dsl 0, interface ISDN Switchtype = primary-net5
Layer 1 Status
DEACTIVATED
Layer 2 Status:
TEI = 0, Ces = 1, SAPI = 0, State = TEI_ASSIGNED
Layer 3 Status:
0 Active Layer 3 Call(s)
Active dsl 0 CCBs = 0
The Free Channel Mask: 0x80000000
Number of L2 Discards = 0, L2 Session ID = 7
Total Allocated ISDN CCBs = 0
If the ISDN line is up and connected with Voice Gateway then the status of the card will be as below.
edledge-vg#sh isdn status
Global ISDN Switchtype = primary-net5
ISDN Serial0/0/0:15 interface
dsl 0, interface ISDN Switchtype = primary-net5
Layer 1 Status:
ACTIVE
Layer 2 Status:
TEI = 0, Ces = 1, SAPI = 0, State = MULTIPLE_FRAME_ESTABLISHED
Layer 3 Status:
0 Active Layer 3 Call(s)
Active dsl 0 CCBs = 0
The Free Channel Mask: 0x800003FF
Number of L2 Discards = 0, L2 Session ID = 7
Total Allocated ISDN CCBs = 0
This is really important to understand the cause of the error so that troubleshooting or remedy will get started soon. As the error says the issue is with the ISDN line so it could be the card or may the issue is at the ISP end. Worth testing the status by rebooting the Voice Gateway.
Hope this article will be helpful to many. If you are planning to upgrade the IOS or image or software of the cisco device and you are confused with different terms of IOS available on the Cisco Software portal then have a look at Cisco IOS or Firmware Release Types it will help you to understand the different types of IOS.
Source: Cisco, Lab, Knowledge Base
EA00020