From: "Gregg N" 

Geo wrote:
> "Gregg N"  wrote in message
> news:Xns965BF11E63FA4gregginvalidinvalid{at}216.144.1.254...
>
>> The IP protocol allows for up to 64k datagrams, but the RFC only
>> requires hosts to handle up to 576 octets, and says not to use
>> larger datagrams unless you know that all the intermediate systems
>> support it. If you control all the hops between the source and
>> destiniation, then this is not an issue. I don't think this
>> limitation occurs too much in practice even when you don't control
>> the intermediate systems.
>
> Ok so I take it you can be pretty sure this isn't what's causing the
> slowness being discussed?

Yes, because I don't care whether the receiver accepts my packets or not. I
am just measuring how fast I can send them. The sender isn't even aware of
what happens to the packets once they leave the computer. UDP does not have
ACKs.

> Maybe fragmentation requires some sort of a response from the other
> end that smaller non fragged UDP packets don't require (a function of
> routers or something)?

IP fragmentation does not require a response. The sender just splits the
packet up into multiple ethernet frames with a fragmentation flag and
offset set in each fragment. The recipient reassembles the fragments. If a
fragment gets corrupted or lost in transit, the sender is none the wiser.

Gregg

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