follow up on gigabit either

Dorian Kim dorian at
Thu Dec 24 04:15:50 UTC 1998

On Wed, Dec 23, 1998 at 08:00:29PM -0800, George Herbert wrote:
> K wrote:
> [useful summary of gigabit ether situation]
> >Steve also made exclnt point that the ATM vs 'promiscuous' medium
> >	have other inherent distinction of potential interest 
> >	to ISPs with policy/privacy/security concerns
> I'm not quite sure I understand this bit; isn't switched ether
> (of any speed) equally secure as an ATM switch would be?

One aspect of this has more to do with on by default vs off by default
nature of traffic in the mesh. In an multiaccess broadcast medium, port A 
can send traffic to port B. In a (virtual)circuit switched environment, 
this can't be done w/o setting up explicit connections between the two 

Given the occasional creative uses of multiaccess broadcast media exchange 
points, this can be seen as a major operational win, although some ATM 
exchange operators set up full mesh of PVCs by default, negating this 

Port filtering on multiaccess broadcast media can provide this feature
if the switches can do this w/o melting.


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