[c-nsp] BGP question : What's the best way for filtering outgoingprefixes?

[Jon Lewis]

On Thu, 18 Aug 2011, Scott Granados wrote:

> Go with option A, community tags are your friend.  It also removes the need 
> for any network statements in your config thus reducing the work in the long 
> term.

You'll probably still need some network statements in your config at least 
for all your own routes.

The best part about using community tags for BGP filtering are, you only 
have to setup an appropriate route-map/prefix-list on the router servicing 
the BGP customer.  Once you receive/accept their route and tag it on that 
router, the rest of your network knows what to do with it based on the 
community tag.

I was absolutely shocked the last time I helped a customer turn up BGP 
with a (primarily cable) transit provider, and was told that the turnup 
was being held up because it required updating prefix filters on their 
core routers, and they could only do that during a maintenance window and 
they weren't allowed to schedule any maintenance windows because a 
tropical storm was threatening to impact the SE US.

----------------------------------------------------------------------
  Jon Lewis, MCP :)           |  I route
  Senior Network Engineer     |  therefore you are
  Atlantic Net                |
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