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Scenario 6-4 Answers 191
for BRI connections. For PRI, the TEI is 0. If the switch type is incorrect and/or the switch
type is changed, save the configuration and reload the router. The new switch type is not
activated until a reload is done.
4
Layer 3 connectivity is dependent on Layers 1 and 2. If they are not active, Layer 3 does
not activate. Table 6-8 shows only a few of the privileged EXEC commands available to
troubleshoot Layer 3.
Table 6-9
ISDN Layer 3 Troubleshooting
Command
Explanation
show isdn status
This command is useful in troubleshooting all 3 layers of the ISDN connection.
It shows (layer by layer) the status of the connection.
debug isdn q931
This command shows the real-time call setup (or lack thereof). You can monitor
the progress of the call in real time.
debug dialer
This enables the real-time dialing and negotiation between the two routers.
show interface bri0
This shows a snapshot of the current status (up/down, and so on) of the
interface.