User manual

Figure 13: Show isdn status output immediately after setting the switch type
Router#show isdn status
The current ISDN Switchtype = basic-ni1
ISDN BRI0 interface
Layer 1 Status:
ACTIVE
Layer 2 Status:
TEI = 64, SAPI = 0, State = TEI_ASSIGNED
Layer 3 Status:
0 Active Layer 3 calls
Activated dsl 0 CCBs = 0
Total Allocated ISDN CCBs = 0
Try the following troubleshooting steps:
1. Verify the switch types are set and consistent. If you change from the current settings, reboot the
simulator and preferably the router.
2. Issue a “shutdown” followed by a “no shutdown” command
3. Issue a “clear interface bri number” command.
4. Reboot the router.
5. Check that the BRI interface does not have a “backup interface” subcommand; remove it if
present.
6. Be sure that the physical interface (i.e., S/T or U) on the device under test matches the Simulator
jack to which it is connected. On a Cisco router, use “show version” or “show controllers” to
conrm the interface type.
Layer 2 Troubleshooting with Cisco routers
Once you have conrmed layer 2 is working but layer 2 either is down or cannot stay up, you need to debug
Q.921, the layer 2 protocol used for ISDN signaling on the D channel.
Figure 14: Example of Layer 2 Debugging
router#debug isdn q921
ISDN Q921 packets debugging is on
router#conf t
r2(cong)#
r2(cong)#int bri 0
r2(cong-if)# no shut
%LINK-3-UPDOWN: Interface BRI0, changed state to up
ISDN BR0: TX -> IDREQ ri = 33114 ai = 127
ISDN BR0: RX <- IDDENY ri = 33114 ai = 127
ISDN BR0: RX <- IDCKRQ ri = 0 ai = 127
ISDN BR0: RX <- IDCKRQ ri = 0 ai = 127
ISDN BR0: TX -> IDREQ ri = 38651 ai = 127
ISDN BR0: RX <- IDREM ri = 0 ai = 82
ISDN BR0: RX <- IDREM ri = 0 ai = 83
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User Manual
2 Port ISDN Simulator