Re: [netext] draft-ietf-netext-logical-interface-support -- multiple incompatible MTU advertisements?

<Basavaraj.Patil@nokia.com> Wed, 16 November 2011 05:34 UTC

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From: <Basavaraj.Patil@nokia.com>
To: <charliep@computer.org>
Thread-Topic: [netext] draft-ietf-netext-logical-interface-support -- multiple incompatible MTU advertisements?
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Date: Wed, 16 Nov 2011 05:34:27 +0000
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Subject: Re: [netext] draft-ietf-netext-logical-interface-support -- multiple incompatible MTU advertisements?
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Hi Charlie,

Using the minimum MTU as the value for the logical IF is probably the right thing to do.
However you can also consider this as a sort of a DoS attack in the sense that you are forcing the MN to use an MTU to a smaller value thereby causing less efficient use of an air IF. 
As an example a wifi network may advertise an MTU of 1280 and if the MN uses this as the default even on the cellular IF, the cellular IF is being used sub optimally.

-Basavaraj

On Nov 16, 2011, at 10:23 AM, ext Charles E. Perkins wrote:

> 
> Hello folks,
> 
> At the meeting this morning, a question was raised
> about the proper behavior on a logical interface if
> more than one value of MTU were advertised on any of
> the links of the interface.  This was discussed in
> the IPv6 working group.  IIRC, the sense of the
> discussion was that this was simply an error.
> See section 6.2.7 of RFC 4861.
> 
> In the case for logical interfaces, it seems to
> me that (a) a device can pick the MTU for whatever
> router advertisement it is using and (b) for the
> purposes of multicast across all links the source
> should pick the minimum of all advertised values.
> 
> Regards,
> Charlie P.
> 
> 
> Regards,
> Charlie P.
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