[Ns-developers] Csma, ethernet length field, NSC and the linkmtu...

[craigdo@ee.washington.edu]

[ ... ]

> SetMtu is expected to fail and return false if the value given is not
> compatible with the configuration of the underlying device. 
> Now, if you
> make the Mtu an attribute, you will need to make sure that 
> setting that
> value through the attribute system conforms to the device's 
> bounds and,
> if these bounds are not static (as is the case for the csma netdevice
> which can be dynamically configured to behave in different ways), you
> will have to provide your own implementation of AttributeChecker which
> performs bounds checking based on the device's configuration.

I think this means we agree.  Let me reiterate:

o No notion of separate PHY and MAC MTU numbers exist in either p2p or CSMA
devices;
o There should be an internal PHY MTU which corresponds to the 1500 byte
enet number;
o There should be a mac level MTU attribute checked against the Phy MTU;
o SetMtu should attempt to set the Mac MTU and return error if it can't;
o GetMtu should return the MAC MTU which is the payload;
o What we're talking about should be explicitly stated in the dox.

-- Craig