maybe lifetime of NAT table element * throughput * expected likelihood of
fragmentation ?
not sure,

Jacni

On Wed, Jun 2, 2010 at 8:36 PM, Lee, Yiu <[email protected]> wrote:

> Agreed. But the problem is the NAT device doesn't know how much buffer it
> will need to reserve for de-fragmentation because it doesn't know how many
> times a packet got fragmented. This opens hole for "Fragmentation Buffer
> Full" attack. I am curious how today most home gateway handles v4
> fragmentation from hosts?
>
>
> On 6/2/10 8:11 AM, "Alain Durand" <[email protected]> wrote:
>
> > Except that, as the AFTR needs to NAT the packet back to the tunnel, it
> needs
> > to reassemble the packet first..
> >
> >    - Alain.
> >
> >
> >
> > On May 28, 2010, at 8:49 AM, Lee, Yiu wrote:
> >
> > Hi Taurn,
> >
> > So the v4 packet is fragmented by the remote host before reaching AFTR?
> If so,
> > the AFTR shouldn¹t wait but pass the fragmented packet untouched with
> > encapsulation. That said, the fragmented v4 packet could be fragmented
> one
> > more time in the AFTR after adding the v6 header overhead. B4 must
> reassemble
> > the v6 fragmented packets before sending to the host. It is the host
> > responsible for reassembling the v4 fragmented packets.
> >
> > Regards,
> > Yiu
> >
> > On 5/28/10 2:23 AM, "Tarun Saxena"
> > <[email protected]<x-msg://766/[email protected]>> wrote:
> >
> > Hello Alain,
> >
> > DS-Lite draft mentions that for big packets, v6 fragmentation must be
> > performed after encapsulation both at the B4 and AFTR. What is the
> expected
> > behaviour in case an already fragmented IPv4 packet is received at an
> > end-point?
> >
> > 1)       Should the end-point wait for all the fragments to turn,
> reassemble
> > the packet and then encapsulate.
> > 2)       Or, it should just handle fragments as ³normal² v4 packets and
> > encapsulate them.
> > a.       What if the encapsulated fragment needs v6 fragmentation?
> >
> > Is there a take from the standards point of view, or are these details
> left
> > open for the implementation to do what it deems fit?
> >
> > Regards
> > Tarun Saxena
> > Ph +91 80 41904390
> > Juniper Networks
> >
> >
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>
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