Aggressive route flap dampening
Can aggressive route flap dampening replace the need for /19 prefix filtering? For instance, could the old Class C space be filtered on the /24 boundary if this sort of flap dampening was put in place? Here is Paul Ferguson's comments from the pagan mailing list:
Again, I mention the fact that aggressive route-flap dampening could be used in the place of prefix length traffic filters, but someone/something needs to educate the latter group to implement a less draconian method of protecting themselves from misbehaving announcements. If I am not remiss, the predominate reasoning for filtering on /19's and longer was an assumption that smaller announcements were responsible for the majority of the routing instability, and that simply blocking these announcements at an arbitrary prefix length would be the simplest way to 'fix' the problem. This may be true, but an alternate method of approach for this problem could solve all of this squabbling once and for all, at least in regard to this issue.
******************************************************** Michael Dillon voice: +1-415-482-2840 Senior Systems Architect fax: +1-415-482-2844 PRIORI NETWORKS, INC. http://www.priori.net "The People You Know. The People You Trust." ********************************************************
Michael, I believe the primary purpose of the /19 filtering was to reduce the size of the route table. The increased stability this caused was just a happy side affect.
Can aggressive route flap dampening replace the need for /19 prefix filtering? For instance, could the old Class C space be filtered on the /24 boundary if this sort of flap dampening was put in place? Here is Paul Ferguson's comments from the pagan mailing list:
Again, I mention the fact that aggressive route-flap dampening could be used in the place of prefix length traffic filters, but someone/something needs to educate the latter group to implement a less draconian method of protecting themselves from misbehaving announcements. If I am not remiss, the predominate reasoning for filtering on /19's and longer was an assumption that smaller announcements were responsible for the majority of the routing instability, and that simply blocking these announcements at an arbitrary prefix length would be the simplest way to 'fix' the problem. This may be true, but an alternate method of approach for this problem could solve all of this squabbling once and for all, at least in regard to this issue.
******************************************************** Michael Dillon voice: +1-415-482-2840 Senior Systems Architect fax: +1-415-482-2844 PRIORI NETWORKS, INC. http://www.priori.net
"The People You Know. The People You Trust." ********************************************************
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