RE: [lwip-devel] IP fragmentation

[Goldschmidt Simon]

> > What also disturbs me is that, 
> > because there is only one reassembly-buffer, you can only receive 
> > fragmented IP-packets from one host at a time. That's because I
didn't 
> > enable IP_REASSEMBLY...
> > Or am I wrong and this would never happen??
> 
> This is correct and intentional - more frags to reassemble 
> means more memory, it's as simple as that.

If fragmented packets would be temporarily stored in their corresponding
pbuf instead of copying them into reassbuf, you would waste less memory
since you don't have to provide the maximum memory all the time using
only pbuf memory if you really have something to reassemble. And the
amount of pbufs being in the reassembly buffer could easily be
configured.
(see task #6861 for my ideas about that)

> You should try and 
> avoid getting fragmented packets in the first place!
> Of course if lwIP could implement path MTU discovery, it 
> could keep up its side of the bargain.

Agree, but isn't reassembly the wrong side for that?


Simon