North American Network Operators Group

Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical

Re: Packets from net 10 (no, not the lyrics)

  • From: Kenneth E. Gray
  • Date: Tue Sep 23 14:03:20 1997

And that would be process switching to Null0, I believe.

At 08:22 AM 9/23/97 -0700, Kevin Oberman wrote:
>> Date: Tue, 23 Sep 1997 10:45:19 -0400
>> From: "Randall S. Benn" <[email protected]>
>> I think you'll find that your router's CPU will be happier if you just dump
>> the 1918 networks to the bit bucket on your border routers with a static
>> route via interface Null0:
>>    ip route null0
>>    ip route null0
>>    etc.
>> Considering resource utilization on the router, it is cheaper to do a
>> routing table look-up than it is to do ACLs.  Also, when you're doing
>> outbound filtering on the router, you have to do a routing table lookup
>> first before you can do outbound filtering.  Save a step and just do the
>> routing table lookup.
>I don't think so. The static routes will require processing every
>packet destined for the and nets, but you will
>still have the bad route. The CPU will have to deal with any traffic
>for and any interior routers will forward packets since you
>have a route.
>On the other hand, a filter on the BGP session will block the route
>from being accepted and only require CPU action once...when it is
>announced. You have no route to these nets and can't propagate the
>routes since you don't have them.
>Andrew clearly has the correct approach.
>R. Kevin Oberman, Network Engineer
>Energy Sciences Network (ESnet)
>Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
>E-mail: [email protected]			Phone: +1 510 486-8634
Ken Gray                                                 ||        ||
ISP Systems Engineer                                     ||        ||
Reston, Virginia   USA                                  ||||      ||||
tel: +1.703.397.5942                             ..:||||||:..:||||||:..
e-mail: [email protected]                           c i s c o S y s t e m s
fax: +1.703.397.5999