James Carlson wrote:
> That's true, except that this isn't so simple.  The "optimal" MTU to
> use also has to take into account the attached hardware and the peers.
> At least for Ethernet, the MTU must be set the same on all systems on
> a given subnetwork.  That's inescapable.

You're saying that the MTU must be the same for everythin on the subnet?  I'm 
not a network guru, but it seems to me that there's some wiggle room in there.

All listeners on the network must accept a packet up to the MTU of the system 
sending them data.  They don't care about anything else happening on the 
network.

For example, if the 1st-hop router can accept packets up to 9000 bytes, but the 
Solaris system never sends anything bigger than 1500B (or 8150B), everything's 
happy.

The reverse of that traffic (the router sends 9000B packets to Solaris) would 
be dropped as too long.

If there is a driver- and hardware- optimized "Max Transmit TU" and the 
subnetwork has a different (but bigger) MTU, wouldn't it make sense to split 
out those two tunables?  Default MTTU == MTU, but can be tweaked at the driver 
layer (for example in driver.conf)

Or would that be too many network tunables?

--Joe
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