[8176] in North American Network Operators' Group
Re: consistent policy != consistent announcements
daemon@ATHENA.MIT.EDU (Alan Barrett)
Fri Mar 14 12:21:23 1997
Date: Fri, 14 Mar 1997 18:57:51 +0200 (GMT+0200)
From: Alan Barrett <apb@iafrica.com>
To: Randy Bush <randy@psg.com>
cc: nanog@merit.edu
In-Reply-To: <m0w5ZNn-0007zbC@rip.psg.com>
> > M
> > / \
> > A B * Peer link
> > | * | Customer link
> > RRRRRRR
> > Point1 * * Point2
> > VVVVVVV
> How is R supposed to recognize some likely disjoint set of of what A
> announces to R as coming from M through B so as to recognize it as a
> customer prefix? Note that the paths from M to R through A and B can
> be longer than depicted and that M's address space may not be taken
> from R's, A's, or B's.
R could request A to provide it with a list of ASes for indirect
customers behind A. (R probably already does that.) That would be
sufficient information for R's router at the R/B interconnection to tag
M's routes as customer routes. Essentially, when R's router at the R/B
interconnection receives a route with path "B M", it could use the fact
"M is an indirect customer" rather than "B is a non-customer" to tag the
route appropriately.
Alternatively, R could make the decision using prefixes rather than AS
numbers, and could make it at the R/V[Point2] outbound announcement
point rather than at the B/R inbound announcement point.
--apb (Alan Barrett)
