Internet Backbone Index

Mon Jul 14 00:27:30 UTC 1997

On Sun, 13 Jul 1997, Stephen Balbach wrote:

> > What's an IP switch? If you can define what this is other than a marketing
> > stunt, I'd appreciate it.
> 
> Routes the first packets and switches the rest based on "flows". It 
> is not dependent on layer 2 or PVC's to determain the correct 
> route? This is what Ive read from the mfg's who claim higher pps via this 
> method then straight routing. 

Not really. Given the nature of traffic in Internet, the "cost" of flow set up
and maintenance pretty much outweigh whatever gain you get from from
cut-through switching.

This is actually quite similiar to why forwarding caches in routers aren't
very useful in the current Internet.

Now, if the device had specific functions that requires it to perform actions
on per-flow bases on a traffic that was deterministically long flow oriented,
it would be a gain, but this sort of thing is not very useful for the Internet
as we have it.

> > Since people seem to think that switch has some magically theraputic quality
> > to network performance I wonder why Bay marketing hasn't started making a big
> > deal about the fact that their BCNs function as frame relay switches. 
> 
> I assume at some level it makes sense to do switching for topology 
> reasons. But for performance, it is not a benefit?

Depends.

-dorian