How to Configure Microsoft LLDP Protocol Driver

Question

Windows 10 has activated the "MsLldp" Service on Network Adapters. This "MsLldp" Service sends LLDP Ethernet-Frames to managed Switches so that they show up in the LLDP Neighbors Table.

I like to get Information how to Configure this Service.

Default configuration is, that it only sends the MAC-Address of the Ethernet-Adapter as "LLDP Chassis Subtype". How to Configure this Service to send for example "System name" or "Port Description" Information ...?

Answer 1

Hello @Gunnar Haslinger ,

Unfortunately, using the registry to change the behaviour of Mslldp looks like a dead end.

This is what I have found: the driver always tries to read a REG_SZ value named ChassisId from the service's Parameters subkey; if this fails, the service reads the ComputerName value from the key HKLM\SYSTEM\CurrentControlSet\Control\ComputerName\ComputerName. The result of this process (i.e. either the ChassId or ComputerName value) is stored in a global variable which appears not to be used (apart from initialization and cleanup).

It is still possible that Mslldp is capable of more than we suspect (perhaps controlled via IOCTLs) but I doubt it.

Gary

Answer 2

Hi,

Based on my research, it seems that Microsoft LLDP can only send the MAC-Address to managed switch.

The similar thread has discussed before, you could have a look:

LDWin - Link Layer Discovery Client for Windows (LLDP/CDP)

Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.

Best Regards,
Candy

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Answer 3

Thanks for your pointer @Candy Luo

I already tried WinLLDPservice as alternative which works fine, but sends wrong "System Capabilities / Auto Negotiation" (which is sent correct by MSLLDP).

If the only functionality of MSLLDP Service is to send the MAC-Address, why is this Service existing? MAC-Addresses could be even identified by Checking the SourceAddressTable of a switch, therefore no LLDP would be needed.

Answer 4

Hi @Gunnar Haslinger ,

Since there are limited Microsoft documents talking about MSLLDP Service, I am not sure whether there is someplace in windows can configure this service to send for other Information.

If you want to get exact confirm, I would suggest you open a case with Microsoft where more in-depth investigation can be done so that you would get a more satisfying explanation and solution to this. Here is the link:

https://support.microsoft.com/en-us/gp/customer-service-phone-numbers

Appreciate your understanding. :）

Best Regards,
Candy

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Answer 5

Hello @Gunnar Haslinger ,

Just like Candy, I could not find any information on the web. However looking at the strings inside mslldp.sys and the debug symbols, it might be possible to send the computer name. The strings include:

ChassisId
ComputerName
Mslldp\Parameters
ComputerName\ComputerName
Mslldp\Parameters\Agents\%s-%u

The symbols include:

mslldp!lldpReadComputerName

It might take some trial and error or reverse engineering, but sending the computer name may well be possible...

Gary