Tài liệu Remote ISDN Site not Answering doc

1-2 Semester 8 Internetwork Troubleshooting v1.0 - Lab 9.2.4 Copyright  2001, Cisco Systems, Inc.
Lab 9.2.4: Remote ISDN Site not Answering
ISDN
Atlas 550
192.168.16.0/24
4/1
4/2
BRI0/0
51055512340001
51055512350001
BRI0/0
51055540000001
51055540010001
.3
.7
192.168.0.0/24 192.168.200.0/24
SanJose3 London
.3 .1
Fa0/0
Fa0/0

Objective:
Establish an ISDN BRI to ISDN BRI call from a branch office to a central
site.
Scenario:
The London network administrator informs you that there is no WAN
connectivity. ISDN connectivity has been lost between London and San
Jose. After some investigation you contact the San Jose administrator.
Based on logs maintained in San Jose, there has not been a successful
ISDN session since yesterday when a security audit was performed.

Though International Travel Agency (ITA) does not rely on sensitive “top-
secret” information, the database of customer information has to be kept
confidential. Also, the integrity of the reservation systems is mission-critical.
Partners and customers need access to information, but the ability to modify
information must be restricted and monitored.
Step 1
Cable the lab as shown in the diagram.
Load the Lab9-2-4-London-BrokenConfig.txt and Lab9-2-4-SanJose3-
BrokenConfig.txt configuration files.
Step 2
Start by turning on debug dialer and debug isdn events while
attempting to ping London from SanJose3.
Is the call being connected?




2-2 Semester 8 Internetwork Troubleshooting v1.0 - Lab 9.2.4 Copyright  2001, Cisco Systems, Inc.
Step 3
Gather more information by attempting an ISDN session with PPP specific
debugging turned on.
SanJose3#undebug all
All possible debugging has been turned off
SanJose3#debug ppp authentication
PPP authentication debugging is on
SanJose3#debug ppp negotiation
PPP protocol negotiation debugging is on

London#undebug all
All possible debugging has been turned off

London#debug ppp authentication
PPP authentication debugging is on
London#debug ppp negotiation
PPP protocol negotiation debugging is on
London#ping SanJose3
Step 4
Based on the output of the previous commands, what are some
possible reasons an ISDN call cannot be established between
London and SanJose3?



What is your action plan to resolve the problem and establish ISDN
connectivity between London and SanJose3?




Step 5
Implement your action plan and observe results by attempting an ISDN
session.



Step 6
Document your work with summary of problem, troubleshooting methods
and resolution.