Network topology [Solved]

John Kemp kemp at network-services.uoregon.edu
Fri Nov 15 22:42:36 UTC 2013


Ah, sorry.  Resurrected an old one there...
;-/

/jgk

On 11/15/13 2:41 PM, John Kemp wrote:
> 
> I know Carlos did a bunch of work to build this
> into Netdot, i.e. discover L2, draw usable graphs.
> 
> Here's a link to the last NANOG presentation:
> 
> http://www.nanog.org/meetings/nanog49/presentations/Tuesday/Vicente-netdot-presentation-nanog49.pdf
> 
> John Kemp
> 
> On 10/15/08 7:18 PM, Dale W. Carder wrote:
>>
>> On Oct 15, 2008, at 1:35 PM, Colin Alston wrote:
>>
>>> On 2008/10/15 06:29 PM Colin Alston wrote:
>>>> Is there any kind of cunning trick to detect standard layer2 switches
>>>> along a path without stuff like STP?
>>>
>>> Apparently there isn't. Lots of people mentioned other tools, the
>>> problem there is they have one thing in common which is polling SNMP.
>>> I think it scales badly in general.
>>
>> What is your reasoning behind this claim?  I would claim
>> quite the opposite compared to CLI or TL1.
>>
>>> Maybe there should be something (I mean like, someone should come up
>>> with a standard :P) to trace switches in a path
>>
>> I've written a cruddy script that given a seed bridge, scrapes
>> L2 information obtained via CDP (I guess it could do LLDP, too)
>> and does a breadth-first search through a network.  Then I just
>> dump that into gnuplot format.  Getting the data is easy compared
>> to visualization.
>>
>> A coworker of mine has written script to ask Rapid-STP speaking
>> switches about their current topology and builds a graph again
>> in gnuplot format.
>>
>> A more challenging approach would be to scrape the mac forwarding
>> tables and stitch things together.  This would have to be done
>> per-vlan.  I think this approach (or similar) might be done by
>> Openview's L2 featureset.
>>
>> Dale
>>
>> -- 
>> Dale W. Carder - Network Engineer
>> University of Wisconsin / WiscNet
>> http://net.doit.wisc.edu/~dwcarder
>>
>>
> 




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