[vortex] Sorry to trouble you, I wonder if you could help me.
Wed Apr 17 23:34:02 2002
Thank you for your help and kindness. Now I know more about MAC
loopback and PHY loopback. :-)
Exactly how to do remote loopback control is an issue. somebody is
trying to decide. In general, a signal is sent to the other end of the
link. That signal may be carried within the preamble bits or within an
Ethernet control frame. The signal is intepreted by the far end as an
indication to go into loopback mode, where either bits or frames are
received and then echoed out the interface.
I want to know what your idear about that?
You know that the MAC loopback test occurs before the transceiver,
while the PHY loopback occurs after the transceiver.
So I have another detail questions:
How to decide the MAC loopback test and the PHY loopback test success or
From: Bogdan Costescu [mailto:firstname.lastname@example.org]
Sent: 2002?4?18? 1:57
To: biwu.xie [???]
Subject: Re: [vortex] Sorry to trouble you, I wonder if you could help me.
On Wed, 17 Apr 2002, [big5] biwu.xie [ÁÂ¥²ªZ] wrote:
> 1) what are MAC loopback and PHY loopback?
AFAIK, a loopback means that the Tx path is wired to the Rx path, so that
whatever is sent comes back immediately. The fact that you have them
integrated on the card makes easy to test both paths without the need for
an external device.
> 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" ?
> Wish you can give me some experience and documents about them.
You can always register for free as a developer on the 3Com site and have
access to the documentation in PDF format. That's all I have, anyway.
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