Re: TOE brain dump

Lincoln Dale
2003-08-07T02:14:47Z

At 03:01 AM 7/08/2003, Andy Isaacson wrote:
> > > Just to be clear, I am asking for an example of a Gigabit Ethernet
> > > switch that supports cut-through switching. I contend that there is no
> > > such beast commercially available today.

i concur.
"cut-through" is generally marketing these days.

there are some switches in the marketplace today which do cut-through
switching, but fall back to store-&-forward when:
- there is congestion in a port (i.e. output port is busy; queue frame)
- the sender & receiver are of mismatched speeds
- the receiver initiates gig-e flowcontrol

note that "cut-through switching" means that you lose the ability of the
switch to drop corrupted frames. i.e. how can it check the ethernet crc32
and validate it until its all been sent? in short, it cannot.

in real-world traffic scenarios, there is very little real-world scenarios
where cut-through actually occurs.

cheers,

lincoln.