> Joe seems to want to be able ot specify the size of the packets transmitted
> to the user. Which isn't what PPP is desinged to do - each end tells the
> other end the max size it can *receive*. So when you dial into a PM the
> PM tells the client it's MTU - and the client tells us the max size to
> send to it.
I think this is what Joe's getting at. Our Linux term servers running
pppd have options for:
mru <n>
Set the MRU [Maximum Receive Unit] value to <n> for
negotiation. pppd will ask the peer to send pack-
ets of no more than <n> bytes. The minimum MRU
value is 128. The default MRU value is 1500. A
value of 296 is recommended for slow links (40
bytes for TCP/IP header + 256 bytes of data).
mtu <n>
Set the MTU [Maximum Transmit Unit] value to <n>.
Unless the peer requests a smaller value via MRU
negotiation, pppd will request that the kernel net-
working code send data packets of no more than n
bytes through the PPP network interface.
> 1500 has always worked fine for me, as long as the stack wasn't buggy
> (like Trumpet 2.0b).
Trouble is, Trumpet 2.0b is pretty darn popular...or at least was until
win95 started taking over. I still remember the day our systems suddenly
became incompatible with Trumpet when using a MTU of 1500. Apparently it
was due to some fix in the linux networking code in 1.3.x. We talked a
lot of people through resetting their MTU. Now I have both set a bit
lower than 1500...so it will ask client stacks not to send > n bytes per
packet and will not send them > n bytes per packet. Nobody's complained.
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