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" <m4rtntns@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 <tore@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 (job@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