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Windows 7: A unique observation with Link Layer mapping.

16 Jun 2016   #1

Win 7 SP1 Professional 64 bit
A unique observation with Link Layer mapping.

The conditions:
(2) Lenovo L512 computers with identical hardware running Win 7 Pro. Both are connected to the modem using CAT 5 cables.

Centurylink modem setup for IPv6.

All necessary Win 7 Services for computer discovery and for the mapping function selected and started.

What I have discovered.

In the case of my home network, if I have the Link Layer Topology Discovery Responder ("LLTDR") checked "yes" on both machines Realtek PCIe GBE Family Controller (ethernet adapter) I get NO map of my network. Instead, I get the message, "An error happened during the mapping process" on both machines.

If, I uncheck the LLTDR box on one machine, I get a map on both machines. The maps are different, and display as follows.

On the computer where I have checked the LLTDR box, I get a map that shows the proper connection of this machine to the hub and then to the router. There is NO "discovered" picture of the other computer, either in the top section or in the section at the bottom ("discovered devices that can not be placed in the map.")

On the computer with the LLTDR box unchecked, I get a map that shows the proper connection for the other computer to the hub and then to the router. As for this computer, the map shows the machine connected to the hub with an intermediate ? for this connection.

I have researched the problems others have had in getting the mapping function to work correctly, and I have found nothing that gives me an understanding of why unchecking one computer's LLTDR program allows for maps to be displayed on BOTH machines, albeit incomplete on the "unchecked" LLTDR machine.

It seems I am quite close to getting the mapping function to work correctly on both machines. Perhaps there is some sort of collision problem taking place. I would appreciate any insights into my situation.

My System SpecsSystem Spec

 A unique observation with Link Layer mapping.

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