From: James (james@towardex.com)
Date: Sat Aug 07 2004 - 21:32:24 GMT-3
Hi Nikolai,
> BTW, what's "YMMV"?
YMMV stands for "Your Mileage May Vary" :)
But like I said, this is one of those situations where your preference level,
experience level and business requirement level come to play in terms of
deciding where you want to go.
IMHO, when doing BGP, especially on a large scale backbone level, like Howard
previously suggested, I'd look after begin looking at RPSL (Routing Protocol
Specification Language; http://www.irr.net/docs/rpsl.html) to build your
policy requirements. The language is not very hard, they are simple and straight
forward pretty much[1] to learn as you pick them up.
Either way, using RPSL in the long run gives you scalability to manage policy
requirements on any BGP network whether its meshed formation or confederation
formation, or whether you want to maintain policies with peers/transits and
customers. Some people even go as far as making their AS totally autonomous
in management fassion, where simple click of button generates all relevant
configurations. To add to the whole topic detail, communities are extremely
powerful tool in any AS doing BGP. You can write communities to do things such
as: a) identify the source of the prefixes, b) cause the prefix to get announced
to one peer/transit but not the other, etc, c) cause the prefix to get
blackholed in an automated fassion during DoS attack to a downstream POP or
site, d) enable reverse-cold potato for geographically diverse transit circuits
where you want specific prefixes localized to a region to stay as long as
possible on your transit provider's network to come back to you, hence saving
you money on transport to pull the traffic back, e) in addition to prefix list,
distribute list, etc filtering, create autonomous filtering using communities,
f) automatically cause more specific prefixes to get tagged no-export upon
prefix announcement, as an automated method to deter deaggregation issues, etc
and many many more :) Communities just allow the admin to get creative :)
*[1]: Some relevant links to get started on RPSL language:
o http://www.irr.net/docs/rpsl.html
o ftp://ftp.merit.edu/internet/documents/rfc/rfc2622.txt
o http://www.isi.edu/ra/rps/training/tutorial/
o http://www.occaid.org/tutorial-irrd.html
-J
-- James Jun TowardEX Technologies, Inc. Technical Lead Network Design, Consulting, IT Outsourcing james@towardex.com Boston-based Colocation & Bandwidth Services cell: 1(978)-394-2867 web: http://www.towardex.com , noc: www.twdx.net
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