nanog mailing list archives

Re: Where is the edge of the Internet? Re: no ip forged-source-address


From: <bdragon () gweep net>
Date: Thu, 7 Nov 2002 14:55:47 -0500 (EST)


Ok, so I'll respond to one more of the messages I missed yesterday.

On Mon, 4 Nov 2002, Matt Buford wrote:
On Mon, 4 Nov 2002 sean () donelan com wrote:
The only equipment I'm heard here which has serious issues related to
feature availability is the 12000 (which was never a particularly good
aggregation device to begin with). RPF works fine on 7200, 7500, and
6500, from my experience. I've not used 12000's for customer aggregation
since they historically haven't been designed for or adequate in that
respect.

The above was actually me, not Sean, iirc.

Alot of large providers have 'all 12000' or 'alot of 12000' devices, so
this is a hint at the problem :( Most large, where large == continental,
providers  don't have very many 7200/6500 gear in their network.

Someone else just mentioned running RPF on 12000 without issue, except
for SRP rings. I can't confirm that myself, as we avoided using 12000
for customer aggregation due to their poor performance in that arena.

RPF on ubr7200, 7200vxr, 7500, and 6500 all seem to work fine.

Keep in mind that sometimes what platform you choose 12 months ago you may
get stuck with in a longer term than originally anticipated. That platform
may have been chosen because it was the only viable platform at the
initial buy time :(

Definately understandable.

As such, I can understand providers not being able to apply RPF
immediately
on 12000's, at least unless they are acquiring E3 cards for new installs.


Wow, by E3 I assume you mean: Engine 3... This is a VERY BAD PLAN, if my
experience with them is anything to judge from. Both E2 and E3 cards have
some serious limitations when it comes to access lists and uRPF. For
instance, I've been in config mode where:

int blah1/0.123
ip access<tab>

yields nothing... in other words, 'ip access-group 123 out' is not even in
the valid config for these cards :( even more depressing is the hope that
it'll work and the unfortunate reality that it'll apply to the interface
and never access list any traffic at all :(

Yes, I meant Engine 3, which are the ISE cards. I don't yet have any, but
I'ld be surprised if they don't support acls on subints. Perhaps you meant
E1 and E2? Even if they don't support acls, I'ld be surprised if they
didn't support RPF.

<snip>
From what I've heard, I haven't yet tested these, the E4+ cards are
supposed to answer alot of the existing acl issues. One thing to keep in
mind is that your FIB is limited to ~225k prefixes if you want to use PSA
acls (hardware acls)on a 12000... Supposedly, if you remove PSA acl
functionality you can punt the acl work to the linecard CPU, in reality
the punting never happens and the traffic isn't acl'd :(

Interesting, but shouldn't affect RPF, correct?

<snip>


Current thread: