I can't say what everyone else does, but we only make exact matches from route object to prefix-list
http://www.mellowd.co.uk/ccie > On 30 Jan 2014, at 21:48, "Martin T" <m4rtn...@gmail.com> wrote: > > Job, Tore: ok, I see. So "route" object in RIR routing registry database > for each announced prefix is needed only because some ISPs create filters > exactly the size of the "route" object in database? So for example if there > is a "route" object for 192.0.2.0/24 in RIR database, then ISP-A might > create a following strict prefix-filter entry: > > policy-options { > policy-statement EXAMPLE { > term prefixes { > from { > route-filter 192.0.2.0/24 exact; > } > then next policy; > } > then reject; > } > } > > On the other hand, ISP-B might create loose filter based on the same > "route" object like this: > > policy-options { > policy-statement EXAMPLE { > term prefixes { > from { > route-filter 192.0.2.0/24 upto /32; > } > then next policy; > } > then reject; > } > } > > > PS: this is a theoretical question :) I'm also for keeping the BGP table as > short as possible. > > > regards, > Martin > >> On Thu, Jan 30, 2014 at 5:13 PM, Tore Anderson <t...@fud.no> wrote: >> >> * Job Snijders >> >>>> On Thu, Jan 30, 2014 at 06:51:59PM +0200, Martin T wrote: >>>> >>>> for example there is a small company with /22 IPv4 allocation from >>>> RIPE in European region. This company is dual-homed and would like to >>>> announce 4x /24 prefixes to both ISPs. Both ISP's update their >>>> prefix-lists automatically based on records in RIPE database. For >>>> example Level3 uses this practice at least in Europe. If this small >>>> company creates a "route" object for it's /22 allocation, then is it >>>> enough? Theoretically this would cover all four /24 networks. Or in >>>> which situation it is useful/needed to have "route" object for each >>>> /24 prefix? >>> >>> You should create a route object for each route that you announce, if >>> you announce 4 x /24 you should create a route: object for each /24. >> >> +1 >> >>> ps. Can you please send 20 dollarcent per /24 to my paypal account >>> (j...@instituut.net) with the reference "deaggregation fee"? >> >> Indeed. >> >> Martin, I'd suggest announcing the 4 x /24s to each ISP tagged with the >> no-export community in order to achieve whatever you are trying to do, >> *in addition* to the covering /22. That way you're not polluting Job, >> my, and everyone else's routing tables more than necessary, only your >> own ISPs', but then again you're actually paying them for the privilege. >> >> Tore >>
