North American Network Operators Group|
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why /8 announments are bad...
> > In return, would Covad please consider performing some meaningful form of > route > aggregation or other measures to reduce the amount of noise that is being > passed across the global routing tables that originates from Covad? > > http://www.cidr-report.org/cgi-bin/as-report?as=AS18566&view=4637 > > suggests that Covad could withdraw some 483 BGP routing table entries, > reducing the total number of entires originated by Covad from 490 > to an equivalent set of 8 aggregate routes. perhaps this is not the time/place to raise the point, but I'm coming to the conclusion that there is increasing pushback to -NOT- announce space that is not in active use. So-called "dark" space, i.e. the unused interstitial gaps in delegated space that is the the product of sparse delegation techniques, is perhaps more of a hazzard, esp. wrt. spam/traffic generation than might have been considered in the past. think forged source addresses... if this is a rational line of argument, then two tactics present themselves: 1) announce the individual, more specifics. this has the effect of further bloating the routing table, incuring the rath of the self-appointed routing table police (so watch out Covad, don't do what Telstra did... :) 2) keep my number of routing table entries consistant by "grooming" back my sparse delegations into more homogenous groups, e.g. renumber folks in the four /28s spread across the /19 into a single /26 - then withdraw the /19 and announce the /26 in its place. the number of routing table entries remains consistant and the number of possible entries for forged source addresses is dramatically reduced. Of course this will require a major rethink/ rewrite of most ISPs engineering practice/operating procedures, as it will be much more common to see legitimate, long prefixs in the routing system. as usual, YMMV. --bill