Re: [rohc] Path MTU discovery when having varying MTU

On 19 mei 2009, at 23:14, Joe Touch wrote:

>> Didn't you just suggest to just send enough of the original packet to
>> make ROHC do its thing? That piece of the packet should be small  
>> enough
>> to always fit.

> Yes, except that I also suggested sending the packet without any  
> ROHC on
> it too.

Yes, but then you would still almost never have full-size packets so  
the ROHC only saves bandwidth, not packets. Basically this will buy  
you a 1 byte larger MTU, not worth the trouble because the IPsec  
header already exposes you to PMTUD blackholes anyway.

Ideally, the decapsulator can tell the encapsulator what to do because  
the decapsulator knows about whether it's behind a NAT with  
fragmentation issues. But then there would have to be signaling that  
carries this information.