[lir-wg] AS Number Policy

On Thu, 11 Jul 2002 17:39:41 +0200, Kurt Erik Lindqvist <kurtis at kurtis.pp.se>
wrote:

>> We all know that it's a crappy argument, but lots of people try using it.
>> Especially those who have large legacy implementations that either don't
>> have or don't support filters on customer lines.
>
>I agree with you. Still, the common argument is that it's to complex to 
>maintain and to expensive to install. But again, I am sure the cost of 
>dealing with the effects is close to the same amount. But few people 
>realise this.

I'm not entirely convinced that everyone has this choice.  Some providers have
legacy access kit that simply doesn't support filters on a per-interface basis.
Many are starting to filter on ingress/egress to each PoP which is a good start.

Part of the problem is raw router processing power.  If you've only got enough
processing power to filter inbound *or* outbound, you're more likely to want to
filter inbound (to stop your customers being DoSed) than outbound.  Providers
are filtering outbound, but it's inbound filters that have all the effort
invested in them.  They also tend to be a lot more dynamic thus are a lot better
maintained.

C.