Troubleshooting ISDN Connections - Internetworking Troubleshooting - page 514

LCP failure example:
Jun 10 19:57:59.768: As5 PPP: Phase is ESTABLISHING, Active Open
Jun 10 19:57:59.768: As5 LCP: O CONFREQ [Closed] id 64 len 25
Jun 10 19:57:59.768: As5 LCP: ACCM 0x000A0000 (0x0206000A0000)
Jun 10 19:57:59.768: As5 LCP: AuthProto CHAP (0x0305C22305)
Jun 10 19:57:59.768: As5 LCP: MagicNumber 0x5779D9D2 (0x05065779D9D2)
Jun 10 19:57:59.768: As5 LCP: PFC (0x0702)
Jun 10 19:57:59.768: As5 LCP: ACFC (0x0802)
Jun 10 19:58:01.768: As5 LCP: TIMEout: State REQsent
Jun 10 19:58:01.768: As5 LCP: O CONFREQ [REQsent] id 65 len 25
Jun 10 19:58:01.768: As5 LCP: ACCM 0x000A0000 (0x0206000A0000)
Jun 10 19:58:01.768: As5 LCP: AuthProto CHAP (0x0305C22305)
Jun 10 19:58:01.768: As5 LCP: MagicNumber 0x5779D9D2 (0x05065779D9D2)
Jun 10 19:58:01.768: As5 LCP: PFC (0x0702)
Jun 10 19:58:01.768: As5 LCP: ACFC (0x0802).
Jun 10 19:58:03.768: As5 LCP: TIMEout: State REQsent
Jun 10 19:58:03.768: As5 LCP: O CONFREQ [REQsent] id 66 len 25
Jun 10 19:58:03.768: As5 LCP: ACCM 0x000A0000 (0x0206000A0000)
Jun 10 19:58:03.768: As5 LCP: AuthProto CHAP (0x0305C22305)
Jun 10 19:58:03.768: As5 LCP: MagicNumber 0x5779D9D2 (0x05065779D9D2)
Jun 10 19:58:03.768: As5 LCP: PFC (0x0702)
Jun 10 19:58:03.768: As5 LCP: ACF.C (0x0802)
Jun 10 19:58:05.768: As5 LCP: TIMEout: State REQsent
Jun 10 19:58:05.768: As5 LCP: O CONFREQ [REQsent] id 67 len 25
This repeats every 2 seconds until this occurs:
Jun 10 19:58:19.768: As5 LCP: O CONFREQ [REQsent] id 74 len 25
Jun 10 19:58:19.768: As5 LCP: ACCM 0x000A0000 (0x0206000A0000)
Jun 10 19:58:19.768: As5 LCP: AuthProto CHAP (0x0305C22305)
Jun 10 19:58:19.768: As5 LCP: MagicNumber 0x5779D9D2 (0x05065779D9D2)
Jun 10 19:58:19.768: As5 LCP: PFC (0x0702)
Jun 10 19:58:19.768: As5 LCP: ACFC (0x0802)
Jun 10 19:58:21.768: As5 LCP: TIMEout: State REQsent
Jun 10 19:58:21.768: TTY5: Async Int reset: Dropping DTR
If the connection is asynchronous, the probable cause is a speed mismatch between the router and its
modem, usually as a result of having failed to lock the DTE speed of the modem to the configured speed
of the TTY line. The problem may be found on either or both of the peers; both should be checked. (See
Table 17-1.)
If the symptoms are seen when the connection is over ISDN, the problem likely is that one peer is
connecting at 56K, while the other is at 64K. Although this condition is rare, it does happen; the problem
could be one or both peers, or possibly the telco itself. Use debug isdn q931 and examine the SETUP
messages on each of the peers. The bearer capability sent from one peer should match the bearer
capability seen in the SETUP message received on the other peer. As a possible remedy, you can
configure the dialing speed, 56K or 64K, in either the interface-level command dialer map or in the
command dialer isdn speed configured under a map class.
*Mar 20 21:07:45.033: ISDN BR0: TX -> SETUP pd = 8 callref = 0x2C
*Mar 20 21:07:45.037: Bearer Capability i = 0x8890
*Mar 20 21:07:45.041: Channel ID i = 0x83
*Mar 20 21:07:45.041: Keypad Facility i = 0x35353533373539
This situation is one that may warrant a call to the Cisco TAC. Collect the following outputs from both
peers before calling the TAC:
show running-config
show version
debug isdn q931