[168318] in North American Network Operators' Group
Re: Experiences with IPv6 and Routing Efficiency
daemon@ATHENA.MIT.EDU (Nick Hilliard)
Sun Jan 19 11:47:22 2014
X-Envelope-To: nanog@nanog.org
Date: Sun, 19 Jan 2014 16:11:07 +0000
From: Nick Hilliard <nick@foobar.org>
To: "Mukom Akong T." <mukom.tamon@gmail.com>
In-Reply-To: <CAHDzDLAvCUu1+MJLWpF8M66OnZHkudZ1HXVk5cZOT09Zm3Jdnw@mail.gmail.com>
Cc: NANOG list <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On 19/01/2014 04:00, Mukom Akong T. wrote:
> Have you found them to be more troublesome to process than IPv4 options
> are/were?
The problem is that you can have long EH chains, with one after another.
Generally speaking, most hardware forwarding engines will perform a lookup
based on the first N bytes of a packet.
If arbitrary length EHs are not supported by the hardware, then you have 3
options: forward the packets unilaterally, drop the packets unilaterally or
punt to a cpu/npu. Punting and forwarding both open up denial of service
attacks for hardware-forwarded routers, so generally the only sensible
option is to drop packets with long EH chains.
Nick
