[vortex] Sorry to trouble you, I wonder if you could help me.

Donald Becker becker@scyld.com
Wed Apr 17 15:55:01 2002

On Wed, 17 Apr 2002, Bogdan Costescu wrote:

> On Wed, 17 Apr 2002, [big5] biwu.xie [¥Z] wrote:

> > 1) what are MAC loopback and PHY loopback?

[[ I answered this one privately earlier today. ]]

> > 2) I know that remote loopback can check PHY/MAC level loop back for each
> > layer health. But how to do remote loopback?
> Uh, what is a "remote loopback" ?

Loopback past the PHY (transceiver).  It used to be implemented with a
relay or a physical plug.  Picture a RJ45 with a 2" loop of wire feeding
the Tx back to the Rx pair.

Donald Becker				becker@scyld.com
Scyld Computing Corporation		http://www.scyld.com
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