[c-nsp] Best way to filter local traffic from Internet traffic

Justin M. Streiner streiner at cluebyfour.org
Mon Jun 9 17:26:47 EDT 2008


On Mon, 9 Jun 2008, root net wrote:

> I have a customer that wants a 100/1000 Mb/s pipe into our network for our
> local customers.  This customer is also a customer but he has a dedicated 10
> Mb/s circuit to the Internet and is maxing out on bandwidth.  Wishes to buy
> the 100/1000 Mb/s pipe for our local network access only not Internet.  What
> is the best way to filter this?

If you're running BGP with this customer, or can do so, you can feed them
your local and customer routes and you can have them announce their blocks 
to you over that pipe.  Use the knobs that BGP provides, such as local 
preference or MED to make the prefixes sent and received over the 100/1000 
Mb/s pipe preferred over their normal transit pipe.  This will push 
traffic between your network and theirs over the higher bandwidth link, 
and only use the 10 Mb/s pipe if the larger one is down.

That's a pretty simplistic view of it and doesn't take into account any 
other connectivity the customer might have.

jms


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