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Some points to remember with regards to speed and duplex negotiation and mismatches duplex and speed

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mismatches occur when auto negotiation fails or way manual configurations are mismatched.

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So for example one side is configured to use full duplex and the other side is configured to use half

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duplex or negotiation may fail because of physical problems in the network such as cabling problems

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or a hub somewhere in the network duplex mismatches do cause performance problems.

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Your pings may succeed but the movement of large files may be negatively affected and GDP may especially

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have problems with recovering from duplex mismatch issues so a quick bit of history.

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Originally ethernet was half duplex because devices were connected to hubs.

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So a decision was made that when you can't negotiate with the other side you would revert back to 10

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meg half duplex older devices weren't designed to or to negotiate.

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So the Orta negotiating device would revert back to half duplex mode if it wasn't able to negotiate

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with the other side because it assumed that that device must only support half duplex or negotiation

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of speed and duplex didn't work well in the old days and often caused problems with the speed and duplex

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mismatch.

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If one side is using half duplex on the other side is using full duplex the full duplex side thinks

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that it can transmit it any time even when it's receiving traffic.

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The half duplex side however because it uses carea since multiple access collision detection or CCMA

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slash CD will want the line to be clear before transmitting.

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And when it does transmit and the packet is transmitted by the other side running at full duplex a collision

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occurs.

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So the half duplex side will back off because of the collision and then try and transmit again when

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the line is clear and we'll have the constant issue of late collisions with the full duplex side is

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transmitting data and can start with a half duplex side.

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In other words it can use up all the bandwidth causing a lot of collisions and retransmissions on the

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half duplex side that would cause the frames on the half duplex side to queue up and eventually be dropped

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when looking for problems.

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Have a look at the areas which I'll demonstrate in a moment on the full duplex side you will see errors

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such as CRC errors or runs on the half duplex side you typically see late collisions and Prep's and

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buffer overloading management systems from companies such as solar winds and others allow you to see

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where you've got Duplaix problems on your network and help you resolve these issues more easily.