RE: Partial vs Full tables

[Drew Weaver <drew.weaver () thenap com>]

This is just my experience so do whatever you want with that.

The only time we have ever noticed any sort of operational downside of using uRPF loose was when NTTs router in NYC 
thought a full table was only 500,000 routes a few years back.

That is a fairly real consideration though. =)

-----Original Message-----
From: NANOG <nanog-bounces () nanog org> On Behalf Of William Herrin
Sent: Thursday, June 11, 2020 12:18 PM
To: brad dreisbach <bradd () us ntt net>
Cc: nanog () nanog org
Subject: Re: Partial vs Full tables

On Thu, Jun 11, 2020 at 9:08 AM brad dreisbach <bradd () us ntt net> wrote:
> uRPF absolutely kills the pps performance or your hardware due to the 
> packet having to be recirculated to do the check(at least this is the 
> case on every platform that ive ever tested it on). use acl's to protect your edge.

Hi Brad,

Don't the ACLs generally live in a partition of the TCAM too? So you're going from two constant-time TCAM lookups per 
packet (route,
acls) to three (route, urpf, acls)? Not rhetorical; getting close to the edge of my knowledge here.

Regards,
Bill Herrin


--
William Herrin
bill () herrin us
https://bill.herrin.us/