Troubleshoot any network problem.

[jai.s401]

How to troubleshoot any network problem.

what is the SOP in a pressured situation (Total Network Down).

what are some simple and powerful tools.

How to solve problem step by step and find the Root cause.

[balaji.bandi]

Troubleshoot any network problem.

This is big term, it all depends on how big the network, may take 1 minute to several days based on the issue.

the first step, need to have a clear network diagram up to date.

what is the issue?

then you need to choose the plan, top to down, down to top diagnosis or from the middle of the network where the issue is nearer.

Most people use NMS to discover the issue along with Netflow, Again based on the "definition of network problem ?"

is it the reachability issue

or performance issue ?

or routing issue?

so on the problem are infinitive

[Martin L]

I agree with BB, it is too big of a topic to describe step by step and depends on your organization network size and type, devices and software used.  One of good books on this topic is older book for retired now CCNP Routing and switching certification and for 3rd exam called troubleshooting.  If I remember correctly, typical steps or standard to TS network is using OSI model approach.  you can start your troubleshooting from layer 7 going down to 1 or start at layer 1 and go up.  Alternatively, you can jump into TS right away with so called spot-check based on common issues and/or history and your experience.   

Regards, ML
**Please Rate All Helpful Responses **

[Giuseppe Larosa]

Hello @Martin L ,

yes I agree

>> One of good books on this topic is older book for retired now CCNP Routing and switching certification and for 3rd exam called troubleshooting.

The book provides a methodology and then explores various technologies providing also useful show and debug commands to use.

One of the most important aspect of the method is :

do a single change and then observe the results

making multiple changes at once and then checking the network can lead to a fix, but then  you don't know which of the change has provided a fix.

Troubleshooting requires experience , hands on work on real devices and you should explore and learn as much as possible your network in normal conditions to create the network baseline.

Just to make an example being able to answer to questions like:

who is the root bridge for VLAN 100 in normal conditions ?

what are the OSPF neighbors of a router in normal conditions ?

what are the routes that I see in show ip route ospf in normal conditions ?

Who is injecting a default route in OSPF in normal conditions ?  ( multiple devices can do it)

This is just to mention a few examples-

Hope to help

Giuseppe

[jai.s401]

That's a really helpful in-sight.!

[jai.s401]

@Martin L can you name the book, please ?

[Martin L]

this one from foundation library which gives more info from cert guide; (you could read 2 of them)

Troubleshooting and Maintaining Cisco IP Networks (TSHOOT) Foundation Learning Guide: (CCNP TSHOOT 300-135)

https://www.ciscopress.com/store/troubleshooting-and-maintaining-cisco-ip-networks-tshoot-9781587204555

also, regular CCNA books by W. Odom have TS sections in them; in every chapter and 1 summary chapter I think.

Regards, ML
**Please Rate All Helpful Responses **