[e2e] TCP Local Area Normal behaviour

[RJ Atkinson]

(With regards to wired Ethernet...)

	Half-duplex Ethernet is increasingly uncommon in commercial or
service-provider environments -- not so much because of any grand plan
as because most such organisations primarily buy better quality Ethernet
switches that are full-duplex (rather than buying Ethernet hubs).  Few
100 Mbps Ethernet deployments seem to be in half-duplex mode.

	I think half-duplex 10Mbps Ethernet is still quite common in 
residential
environments, where the lower price of the Ethernet hub (and the lower
bandwidth demands) are more of a factor in purchasing.

	With 1 GigE specifications, it was theoretically possible to configure
the link to half-duplex, but I do not know of any such deployments (and
not all 1 GigE implementations support that mode of operation).  With 
10 GigE,
full-duplex is the only mode supported in the specifications.

(Of course, wireless Ethernet is a current major deployment trend; its
MAC is somewhat different than these several wired Ethernet MAC 
protocols.)

Cheers,

Ran

On Jan 21, 2005, at 14:29, Matt Mathis wrote:
> But the more pragmatic solution (adopted here at PSC and may other 
> places) is
> to declare half duplex Ethernet to be broken, and eradicate it wherever
> possible.  Where not possible, tell people that the maximum theoretical
> utilization is 1/e (35%), and they should be pleased if they get any 
> better
> than that, because they are operating beyond the designed operating 
> point for
> the media.