do not filter your customers

Christopher Morrow morrowc.lists at gmail.com
Fri Feb 24 20:39:37 CST 2012


On Fri, Feb 24, 2012 at 9:12 PM, Dobbins, Roland <rdobbins at arbor.net> wrote:
>
> On Feb 25, 2012, at 8:59 AM, Christopher Morrow wrote:
>
>> max-prefix already exists... sometimes it works, sometimes it's a burden.
>
> Some sort of throttle - i.e., allow only X number of routing updates within Y number of [seconds?  milliseconds? BGP packets?] would be more useful, IMHO.  If the configured rate is exceeded, maintain the session but stop accepting further updates until either manually reset or the rate of updates falls back within acceptable parameters.

it seems to me that most of the options discussed for this are .. bad,
in one dimension or another :(

typical max-prefix today will dump a session, if you exceed the number
of prefixes on the session... good? maybe? bad? maybe? did the peer
fire up a full table to you? or did you just not pay attention to the
log messages saying: "Hey, joe's going to need an update shortly..."

X prefixes/packets in Y seconds/milliseconds doesn't keep the peer
from blowing up your RIB, it does slow down convergence :(

If you have 200 peers on an edge device, dropping the whole device's
routing capabilities because of one AS7007/AS1221/AS9121 .. isn't cool
to your network nor the other customers on that device :( max-prefix
as it exists today at least caps the damage at one customer.

The knobs available are sort of harsh all the way around though today :(

-chris



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