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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Dampening considered harmful? (Was: Re: verizon.net and other email grief)
On 17-dec-04, at 0:21, Jerry Pasker wrote: ie: does dampening cause more problems than it tries to solve/avoid these days. I don't know what takes more router resources; dampening enabled doing the dampening calculations, or no dampening and constantly churning the BGP table. I would assume dampening generally saves router resources, or operators wouldn't chose to enable it.I generally don't use dampening in most setups, and continuous churning is rare these days, as far as I can tell. I seem to remember that it was mostly caused by bad implementations in the days that it was a big issue. The trouble with dampening is that it only works on stuff that happens beyond the routers your AS talks to. When your neighbors or your own stuff flap you don't get to dampen that. So I guess it's still useful for large networks that have a significant number of views on the same stuff, but it's not really worth the trouble for smaller networks. One reason to be careful with dampening is that flaps can be multiplied. (Connect to routeviews and see the different flap counts under different peers for the same flap at your end to observe this.)
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