Subject: Re: [trill] Fwd: Mail regarding draft-ietf-trill-over-ip

From: Tom Herbert <[email-masked]>
Date: Mon, 4 May 2015 08:25:54 -0700

On Mon, May 4, 2015 at 8:06 AM, Tom Herbert <[email-masked]> wrote:
>  On Fri, May 1, 2015 at 3:48 PM, Joe Touch <touch at isi.edu> wrote:
>> Hi, all,
>>
>> Have you considered GUE as an encapsulation layer?
>
> What would be the best document to look at if someone wanted to learn about GUE?
>

https://tools.ietf.org/html/draft-ietf-nvo3-gue-00 is the starting
point. There are other drafts for extensions (virtualization,
fragmentation, security, etc.). The work of the Encapsulation design
team might also be helpful
(https://tools.ietf.org/html/draft-rtg-dt-encap-01).

>> Encapsulating anything in UDP directly has a number of hazards,
>> including support for at-rate fragmentation, IPv4 ID generation, etc.,
>> that GUE is intended to address.
>
Another difficult area in tunneling over UDP is checksum handling,
particularly for using zero UDP checksums with IPv6 (allowed by
RFC6935, RFC6936). The TRILL-in-IP draft doesn't seem to address this,
but this has been a big concern in other tunneling over UDP proposals
(MPLS/UDP, GRE/UDP) since switches don't typically support checksum.
There is an extension to GUE to address this in
draft-herbert-guecsum-00.

Thanks,
Tom