06-25-2009 02:09 PM - edited 03-06-2019 06:27 AM
Hi every body!
I just want to know how one can disable the auto-negotiation on switch's port? My book says configuring speed and duplex will disable the auto-negotiation.But i read somewhere auto-negotiation is disabled by configuring duplex mode.
thanks a lot!
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06-25-2009 02:15 PM
Sarah
Auto-negotiation is primarily concerned with duplex and not speed. If you disable auto-negotiation then the switch can still detect the speed based on the incoming electrical signal.
I have always worked on the assumption that if you want to disable auto-negotiation you should configure both speed and duplex explicitly.
Jon
06-25-2009 02:56 PM
Sarah
"I also belived that auto-negotiation only help decides the duplex mode."
Sorry if i gave you the wrong impression. Auto-negotiation uses Fast link Pulses (FLP) to determine both the duplex AND the speed.
However if auto-negotiation is disabled then duplex cannot be discovered ie. it must be hardcoded, but speed can be detected using other means eg. the incoming electrical signal.
So a better way to put it -
auto-negotiation on = duplex and speed both determined using FLP.
auto-negotiation off - duplex cannot be detected but speed can using different method.
Jon
06-25-2009 02:15 PM
Sarah
Auto-negotiation is primarily concerned with duplex and not speed. If you disable auto-negotiation then the switch can still detect the speed based on the incoming electrical signal.
I have always worked on the assumption that if you want to disable auto-negotiation you should configure both speed and duplex explicitly.
Jon
06-25-2009 02:44 PM
Thanks Jon!
I also belived that auto-negotiation only help decides the duplex mode. The speed can be determined either by ftp of auto-negotiation process or by simply electrial signals received from the port.
But then i found the following link which shows both speed and duplex mode are decided by auto-ngotiation process. please see the technology ability field in the link.
http://www.iol.unh.edu/services/testing/ge/training/1000BASE-T/ANEG_brief.php
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06-25-2009 02:56 PM
Sarah
"I also belived that auto-negotiation only help decides the duplex mode."
Sorry if i gave you the wrong impression. Auto-negotiation uses Fast link Pulses (FLP) to determine both the duplex AND the speed.
However if auto-negotiation is disabled then duplex cannot be discovered ie. it must be hardcoded, but speed can be detected using other means eg. the incoming electrical signal.
So a better way to put it -
auto-negotiation on = duplex and speed both determined using FLP.
auto-negotiation off - duplex cannot be detected but speed can using different method.
Jon
06-25-2009 03:11 PM
Thanks Jon! you are very articulate as usual.
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