From: Gregg N 

"Geo"  wrote in news:428d5367$3{at}w3.nls.net:

> "Gregg N"  wrote in message
> news:428cc122$1{at}w3.nls.net...
>
>> The limiting factor will not be the maximum length allowed by the IP
> header,
>> but the maximum length allowed by the Ethernet frame into which it is
>> inserted.
>
> Then what is this discussing?
>
> http://www-
> mice.cs.ucl.ac.uk/multimedia/misc/tcp_ip/8810.mm.www/0098.html

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.

Higher level protocols such as TCP allow the two sides to negotiate the
maximum size of datagram that will be used. The article you cited refers to
the negotiation used in TCP that allows the two sides to agree on a maximum
segment size. The term "segment" is the name TCP gives to the
data it stuffs in an IP datagram.

Gregg

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