RE: UDP+Fragmentation (was: "Deprecate")

["C. M. Heard" <[e-mail]>]

On Tue, 6 Aug 2013, Templin, Fred L wrote:
> One other thing for now is that Mike's proposal doesn't even
> address the attack vector that 'draft-bonica-6man-frag-deprecate'
> is concerned about. To address the tiny fragment concern, the
> protocol must ensure that tiny fragments cannot ever be created.

That is incorrect, or at least a red herring.

As draft-bonica-6man-frag-deprecate Section 2.3 points out, tiny 
IP-layer fragments are a problem because thsy can be crafted so that 
the L4 header, or a significant part thereof, does not appear in the 
initial IP fragment.

In the proposal I floated (or variants thereof, like a UDP 
replacement with a new protocol number) where L4 segments are used 
_instead_ of IP fragments that cannot happen, because the L4 header 
appears in front of _each_ segment -- just as with TCP.  Tiny 
transport layer _segments_ have not been identified as a problem.

//cmh