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156 Chapter 6: Using ISDN and DDR Technologies
debug ppp multilink Command
Executing the debug ppp multilink command monitors the PPP connect phase. Example 6-20
shows sample output of a ping triggered call.
debug dialer Command
There are many more commands and command outputs that are useful in troubleshooting the
dial process in general. For instance, the debug dialer command is one of the best tools to use
in figuring out what traffic is attempting to traverse the ISDN link. Example 6-21 shows the
debug dialer command output.
Example 6-20
debug ppp multilink Command Output
RouterA#debug ppp multilink
*Apr 14 03:22:10.489: %LINK-3-UPDOWN: Interface BRI0:1, changed state to up
*Apr 14 03:22:10.497:%LINEPROTO-5-UPDOWN: Line protocol on Interface BRI0:1,
changed state to up
*Apr 14 03:22:10.520%LINK-3-UPDOWN: Interface BRI0:2, changed state to up
*Apr 14 03:22:10.554: BR0:1 MLP: O seq 80000000 size 58
*Apr 14 03:22:10.558: BR0:2 MLP: O seq 40000001 size 60
*Apr 14 03:22:10.586: BR0:1 MLP: I seq 80000000 size 58
*Apr 14 03:22:10.590: BR0:2 MLP: I seq 40000001 size 60
*Apr 14 03:22:10.598: BR0:1 MLP: O seq 80000002 size 58
*Apr 14 03:22:10.598: BR0:2 MLP: O seq 40000003 size 60
*Apr 14 03:22:10.629: BR0:1 MLP: I seq 80000002 size 58
*Apr 14 03:22:10.629: BR0:2 MLP: I seq 40000003 size 60!!!
*Apr 14 03:22:10.630:Success rate is 94 percent (47/50), round-trip min/avg/max =
36/41/128 ms
*Apr 14 03:22:10.637: BR0:1 MLP: O seq 80000004 size 58
*Apr 14 03:22:10.641: BR0:2 MLP: O seq 40000005 size 60
%LINEPROTO-5-UPDOWN: Line protocol on Interface BRI0:2, changed state to up
*Apr 14 03:22:10.669: BR0:1 MLP: I seq 80000004 size 58
Apr 14 03:22:11.330:%ISDN-6-CONNECT:InterfaceBRI0:2 is now connected to 2145552223
RouterB
Example 6-21
debug dialer Command Output
RouterA#ping 10.12.1.2
%SYS-5-CONFIG_I: Configured from console by console
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.12.1.2, timeout is 2 seconds:
BRI0: Dialing cause ip (s=10.12.1.1, d=10.12.1.2)
BRI0: Attempting to dial 2145552222.
%LINK-3-UPDOWN: Interface BRI0:1, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface BRI0:1, changed state to up.!!!
Success rate is 60 percent (3/5), round-trip min/avg/max = 36/41/52 ms
%ISDN-6-CONNECT: Interface BRI0:1 is now connected to 2145552222 RouterB