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Conference noted::etherworks

Title:EtherWORKS Notes Conference
Notice:WWW server at http://ftp.digital.com/pub/DEC/adapters/
Moderator:NETCAD::STEFANI
Created:Wed Sep 01 1993
Last Modified:Thu Jun 05 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:1318
Total number of notes:5673

1265.0. "Product Manager for DE500" by NETRIX::"[email protected]" (Kernel::FREKES) Mon Feb 24 1997 09:22

Folks

I am trying to find who the product manager for the DE500 is. I have a
question
about the autosensing/auto-negotiation. 

1. What is the difference between Auto sensing and auto-negotiation?

2. What does the card do/send onto the network during autosensing?

3. Will plugging a loopback into the DE500, cause the autosensing to just 
select a speed, or will it fail.

Any info would be greatly appreciated.

Steven F
[Posted by WWW Notes gateway]
T.RTitleUserPersonal
Name		DateLines
1265.1NETCAD::FERGUSONMon Feb 24 1997 10:0125
The product manager for DE500 is George Nielsen (delni::g_nielsen).

> 1. What is the difference between Auto sensing and auto-negotiation?

Auto-sensing is an algorithm using information available (link status
and other) to determine the line speed.  It cannot figure out half
vs full duplex.

Auto-negotiation is an industry standard way of nodes advertising what
they are capable of (10-half, 10-full, 100-half, 100-full).  They then 
should operate at the highest common capability.  When auto-negotiation
is not supported by other devices you are attached to, you drop back to
using auto-sense.

> 2. What does the card do/send onto the network during autosensing?
>
> 3. Will plugging a loopback into the DE500, cause the autosensing to just 
>    select a speed, or will it fail.

I don't know the detailed answers to these next two questions, hopefully 
one of the driver developers will have a chance to respond here with more 
information.

Regards,
Janice
1265.2some more info...MAVRIC::POSTNetwork backed up? Give it more fiber.Mon Mar 03 1997 11:0743
Howdy,
    
>
>The product manager for DE500 is George Nielsen (delni::g_nielsen).
>
>> 1. What is the difference between Auto sensing and auto-negotiation?
>
>Auto-sensing is an algorithm using information available (link status
>and other) to determine the line speed.  It cannot figure out half
>vs full duplex.
>
    
    Correct..
    
>Auto-negotiation is an industry standard way of nodes advertising what
>they are capable of (10-half, 10-full, 100-half, 100-full).  They then 
>should operate at the highest common capability.  When auto-negotiation
>is not supported by other devices you are attached to, you drop back to
>using auto-sense.
>
    
    
This is is also known as NWAY...
    
>> 2. What does the card do/send onto the network during autosensing?
>>
    
Nothing appears on the network, and autosensing will not harm a 10 Mb
network.

>> 3. Will plugging a loopback into the DE500, cause the autosensing to just 
>>    select a speed, or will it fail.
>

A loopback will case a DE500-XA to negotiate 100Mb Half Duplex since it
only does autosensing. I think a DE500-AA will also operate at 100Mb half
duplex since the NWAY negoation takes place over the 10Mb channel in half
duplex mode, thus NWAY would not work and autosensing would take over. It
might however negotiate to 100Mb Full Duplex, not sure....

-Don
DE500-XA Software Project Leader.