Dear Support Team,
I'm writing to seek technical support for two issues with the network topology functions.
When I right-click a node, select Topology maps, and choose Layer 2 topology or other topology types, the displayed topology coverage is far too large. It appears that the discovery scope is not restricted by the parameter Topology.DefaultDiscoveryRadius, which is currently set to 5.
Regarding the Network Map feature: when using MSTP links with ISP communication devices deployed between two end nodes, the system sometimes fails to recognize the connection relationship between the two terminal nodes. We presume this issue results from improper configuration of the intermediate ISP-side devices.
We sincerely hope you can offer relevant solutions and troubleshooting suggestions. Thank you very much for your help!
Best regards！

Which exactly is your NetXMS version?

V6.1.2

But this topology issue seems to persist. I'm not sure if it's due to my wrong configuration. Could you please give me some guidance? Thanks a lot!

1. Topology.DefaultDiscoveryRadius

After checking the code, the ad-hoc Topology maps → Layer 2 topology action does send the "use server default" sentinel from the client, and the server is supposed to substitute Topology.DefaultDiscoveryRadius for it. However, we have found a likely bug in how that sentinel survives the trip from client to server (signed/unsigned conversion of the radius field) that can cause the server to use a huge depth instead of the configured one — which matches what you are seeing.

We are opening an internal ticket for the developers to verify and fix. To confirm whether your installation is affected, could you share:

• Server build number and desktop client build number (full version strings).
• A short server log captured during one click on the menu, with these debug tags enabled:
  
  Code Select Expand
  DebugTags = topo.*:7,poll.topology:7,topology.*:7We are interested in the nDepth= value the topology builder receives. If it is something like 4294967295 (or any value other than 5), that is the bug confirmed for your environment.

2. MSTP links via ISP-side intermediate devices

This part is expected behavior, not a bug. NetXMS builds L2 topology by reading FDB, LLDP, CDP and STP tables from each managed device. If the intermediate ISP devices are not managed in NetXMS, there are no neighbor records on the path between your two end nodes, so the server cannot infer the connection. The requirement that all network equipment be registered in the system is documented here: Network topology.

Two ways forward:

• Add the ISP intermediate devices as managed nodes (needs SNMP access from your monitoring zone). Once they participate, LLDP/CDP/STP from each side will let NetXMS stitch the path.
• If you cannot manage them, automatic end-to-end discovery across them will not work — you can add the link manually as a connection on a Network Map.

Useful diagnostic regardless: on each end node's Interfaces tab, the Peer Discovery Protocol column shows how (or whether) each neighbor was discovered — that confirms which protocol is or isn't reaching across the ISP segment.

We will update this thread once the developers confirm the fix for #1.

Thank you very much. The nDepth attribute was not found in the logs. Could you please help check the log files. Thanks a lot!

I just checked on my system, and topology map definitely takes Topology.DefaultDiscoveryRadius into consideration. Are you sure your map has more than 5 hops from seed node? It is hard to understand from screenshot, too many objects. You can try to set zoom level to 50% or 25% and then do refresh - map will be re-layout to fit screen but at new zoom level.
You can also try to set discovery radius to lower value, like 1 or 2 to check that it is working.

We suspect it might be a switch configuration problem, yet it functions normally occasionally. We'll keep an eye on it. Thanks for your help.