[Xorp-users] route flap damping triggers on eBGP duplicate updates?

Bruce Simpson bms at incunabulum.net
Sat May 9 11:50:51 PDT 2009


Hi Jonathan,

Have you actually observed this happening, or is this purely an 
observation based on code inspection?

Jonathan Park wrote:
> Hi Xorp users,
>
> I was looking at XORP code and found that route flap damping can be
> triggered by eBGP duplicate updates (i.e. all attributes are the same),
> giving them the same penalty value of 1000.
>
> Is that true?  If so, is it done intentionally?
>   

It would be really helpful, when reporting this sort of problem on the 
list, if you could illustrate the call graph(s) involved.
I find KScope is an excellent tool for doing this sort of work; it can 
export call graphs via GraphViz, I believe there may be text export for 
call trees in 1 direction also.

So, 1000 is the FIXED value in damping.cc. Other than that, I haven't 
had time to read into this further. Can you elaborate further on how you 
believe this condition is being triggered?

thanks,
BMS



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