Troubleshoot BGP

Troubleshooting BGP

Philip Smith
PacNOG 2 Workshop
Apia, Samoa
18-24 June 2006

PacNOG 2 Workshop

© 2006 Cisco Systems, Inc. All rights reserved.

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Agenda
• Fundamentals of Troubleshooting
• Local Configuration Problems
• Internet Reachability Problems

PacNOG 2 Workshop

© 2006 Cisco Systems, Inc. All rights reserved.

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Fundamentals:
Problem Areas

• First step is to recognise what usually causes problems • Possible Problem Areas:
Misconfiguration
Configuration errors caused by bad documentation, misunderstanding of concepts, poor communication between colleagues or departments

Human error
Typos, using wrong commands, accidents, poorly planned maintenance activities

PacNOG 2 Workshop

© 2006 Cisco Systems, Inc. All rights reserved.

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Fundamentals:
Problem Areas

• More Possible Problem Areas:
“feature behaviour”
Or – “it used to do this with Release X.Y(a) but Release
X.Y(b) does that”

Interoperability issues
Differences in interpretation of RFC1771 and its developments Those beyond your control
Upstream ISP or peers make a change which has an unforeseen impact on your network

PacNOG 2 Workshop

© 2006 Cisco Systems, Inc. All rights reserved.

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Fundamentals:
Working on Solutions
• Next step is to try and fix the problem
And this is not about diving into network and trying random commands on random routers, just to “see what difference this makes”

• The best procedure for “unfamiliar problems” is to
Start at one place,
Deal with one symptom, and learn more about it

PacNOG 2 Workshop

© 2006 Cisco Systems, Inc. All rights reserved.

5

Fundamentals:
Working on Solutions
• Remember! Troubleshooting is about:
Not panicking
Creating a checklist
Working to that checklist
Starting at the bottom and working up

PacNOG 2 Workshop

© 2006 Cisco Systems, Inc. All rights reserved.

6

Fundamentals:
Checklists
• This presentation will have references in