RE: "Deprecate"

["Templin, Fred L" <[e-mail]>]

Hi Ran,

> -----Original Message-----
> From: [e-mail] [mailto:[e-mail]] On Behalf Of
> RJ Atkinson
> Sent: Friday, August 02, 2013 5:06 AM
> To: [e-mail]
> Subject: Re: "Deprecate"
> 
> 
> On 01  Aug 2013, at 18:40 , Templin, Fred L wrote:
> >> If the physical MTU is 1280, then the tunnel MTU will be smaller.
> >
> > Not allowed; the tunnel MUST be able to do a minimum 1280.
> 
> A number of nested tunnel deployments that I'm aware of
> simply do not support that 1280 MTU inside the innermost
> tunnel -- because of accumulated tunnel encapsulation
> overhead.

If you mean an innermost IPv4 tunnel, I have certainly seen that
with IPv4 GRE within IPsec. If you mean an innermost IPv6 tunnel,
that is broken as far as the specs are concerned. The innermost
tunnel is not allowed to send a PTB reporting an MTU size smaller
than 1280.

Thanks - Fred
[e-mail]

> Those nested tunnel deployments are just as real as the PMTUD
> operational issues.  Each is applicable to some environments,
> but not necessarily to all paths and all deployments.
> 
> If this document is to be reality-based, we need to acknowledge
> all of the operational realities that have an impact on this topic,
> not just acknowledge some of the operational realities.
> 
> Yours,
> 
> Ran
> 
> 
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