Path Insight - No Layer2 Information Available / Incomplete path

[BES-SWO]

Hi Community,

when using in Path Insight "Mapping from one IP address to another IP address" we see in often see the notice "Incomplete path" and "No Layer2 Information Available". Can anybody explain what to do to avoid these notices / messages?

BR
Bernd

[LindaYu]

Hi  BES-SWO, 

Thank you for your posts. 

If the mapping is unable to complete, it may be due to the fact that all switches and routers along the path may not be monitored. Add these devices to monitoring for complete visibility of the entire path.

If a switch or router is unable to be monitored (For example: A WAN service provider does not allow SNMP access to the device), then a static route mapping can be made through the device to the far end. 

I've alsp attach PathInsight user guide, and please refer to Pappendix K on how to add a static route to the configuration.

HTH

[BES-SWO]

Hi Linda,
thanks a lot for your hints. I tried some configurations on my own, but I did not succeed with my changes.

In my trace path I just get SNMP data from the first two and the last two network  devices. The other device are maintained by a network provider which did not allow SNMP access to his network devices.

Can you help me with the static route? Which route do I have to enter in the configuration file?

tracert 10.87.19.126

Tracing route to 10.87.19.126 over a maximum of 30 hops

1 1 ms <1 ms <1 ms 10.90.172.221
2 <1 ms <1 ms <1 ms 10.90.172.252
3 31 ms 13 ms 34 ms 10.216.184.61
4 267 ms 260 ms 260 ms 10.216.184.5
5 258 ms 258 ms 258 ms 10.216.184.6
6 258 ms 257 ms 258 ms 10.87.247.106
7 260 ms 260 ms 260 ms 10.87.248.41
8 261 ms 260 ms 261 ms 10.87.248.5
9 259 ms 258 ms 259 ms 10.87.19.126

Trace complete.

BR
Bernd

[GeraldC1]

Hi There,

If it displays "No layer-2 information available", it means that there are no layer-2 switches being monitored for that segment, or we are not getting ARP cache information from routers on that subnet to determine the MAC to IP translation for that segment.

HTH