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

[Bruce Simpson]

Jonathan Park wrote:
> Route flap damping RFC specifies that there should be a penalty for each
> flap. 
>
> From my observation, different implementations interpret "flap" in different
> ways.  Some implementations penalize all updates (like XORP), and some
> implementation (Quagga) penalize an announcement following a withdrawal.
> Cisco penalizes withdrawals and updates with attribute changes but not
> duplicates.  Juniper penalizes all updates but not duplicates.
>
> I was wondering whether this is a bug or it is by design.
>   

I haven't read that RFC, but it does sound like there is ambiguity and 
room for interpretation. To my mind, BGP has become something of a 
'kitchen sink' protocol, I was relieved when the community finally came 
up with a single RFC as a normative reference.

I believe route flap dampening was introduced between XORP releases 1.5 
and 1.6. Off the top of my head, I believe Mark Handley wrote the code, 
he may know more (Cc'd).

thanks,
BMS