RE: [Algorithms] UDP Packet Size

[Jon W. <hp...@mi...>]

> I'm not sure about the internet in general, but on Ethernet the MTU is
> around 1500 octets.  If you subtract IP header (usually 20 octets) and
> UDP header (8 octets) you're left with a 1472 octet payload.  So you'd
> definitely want your packet size to be below that.

Many modems are set at an MTU of 500 bytes or so. (And an ATM cell is 48
bytes of payload, but you don't need to worry about that much as it's all
virtual circuit AFAIK :-)

What I think is more important is that a 500 byte packet running on a 30
kbps modem takes about 170 milliseconds to transmit from the user to the
access point (or vice versa). Then you add routing and transmission for the
rest of the Internet to that, and you're in trouble. The reason is that each
hop along the way between your user and you (or his peer) waits to receive
the entire packet before it forwards it to the next hop. (Well, at least
conceptually).

Cheers,

				/ h+