Re: [v6ops] new draft: draft-ietf-v6ops-cidr-prefix

Nick Hilliard <nick@foobar.org> Wed, 11 February 2015 13:36 UTC

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Date: Wed, 11 Feb 2015 13:35:54 +0000
From: Nick Hilliard <nick@foobar.org>
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Subject: Re: [v6ops] new draft: draft-ietf-v6ops-cidr-prefix
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On 11/02/2015 12:47, fred@cisco.com wrote:
> A new draft has been posted, at http://tools.ietf.org/html/draft-ietf-v6ops-cidr-prefix. Please take a look at it and comment.

I agree with the sentiment of this document but as an observation,
unrestricted longest-prefix-match lookup tends to be circumvented by
vendors in order to provide increased forwarding table capacity.  There's a
curious practical example in the "Cisco Nexus 5000 Series Configuration
Limits" document:

Dynamic routes		16,384 (includes IPv4 and IPv6 routes)
V6 LPM routes		128 entries

It would be interesting to see why the difference between v4 and v6 lpm
lookup entries is greater than 4x.

Otherwise, I support this doc.


Nick