With the suggestion from Adam Thompson above, I was able to figure out how to solve this.

First: use developer tools / console to identify the error e.g.

Uncaught Error: Can not create edge `...` with nonexistant target `dXXX`

Second, view page source for the traffic map and search for the failing target and pull the relevant line, in my case it was

{{

},}}

I then went into the database and did a

select device_id,port_label from ports where port_id = '19691';

This showed me that the issue was with an ignored device that had been monitored prevously but subsequently disconnected.

After deleting this device, network traffic map now works fine.

Hopefully this can help someone else!

I've only just remembered that this is still a problem for me!

Very interesting that you suggest this - because I know for a fact we DO have a self-loop on a network device!

It was a historical requirement which is thankfully nearly obsolete, so as soon as I can finally get rid of it, I'll check to see if that helped anything.

Thanks!

FYI, I've narrowed it down to a single device that Observium refuses to map.  I get this in the browser 'Console':

Uncaught Error: Can not create edge `08236114-4c78-41d0-a0c9-0797837661db` with nonexistant target `d0`

    at Ee (cytoscape.min.js?v=23.2.12520:23:11977)

    at Ps.restore (cytoscape.min.js?v=23.2.12520:29:85677)

    at new Ss (cytoscape.min.js?v=23.2.12520:29:82208)

    at ll.add (cytoscape.min.js?v=23.2.12520:29:89871)

    at cytoscape.min.js?v=23.2.12520:32:61399

    at cytoscape.min.js?v=23.2.12520:32:61651

    at cytoscape.min.js?v=23.2.12520:32:61195

    at new ll (cytoscape.min.js?v=23.2.12520:32:61200)

    at _c (cytoscape.min.js?v=23.2.12520:32:218041)

    at HTMLDocument.<anonymous> ((index):1020:26)

Ee @ cytoscape.min.js?v=23.2.12520:23

Ps.restore @ cytoscape.min.js?v=23.2.12520:29

Ss @ cytoscape.min.js?v=23.2.12520:29

add @ cytoscape.min.js?v=23.2.12520:29

(anonymous) @ cytoscape.min.js?v=23.2.12520:32

(anonymous) @ cytoscape.min.js?v=23.2.12520:32

(anonymous) @ cytoscape.min.js?v=23.2.12520:32

ll @ cytoscape.min.js?v=23.2.12520:32

_c @ cytoscape.min.js?v=23.2.12520:32

(anonymous) @ (index):1020 

looking at the source for the webpage, the link to the non-existent `d0` object references a port `Eth31`, on router `um-rtr-1` which - to work around platform limitations - is a routed port looped back into a switched port Eth32 on the same router.

I also see that the regular map (the one located at `/map`) doesn't show the loopback either:

Is there perhaps some code somewhere that assumes no-one would deliberately create a self-loop on a network device?

I also get the blank screen 99% of the time, but it's dependent on what devices I add to the map.

Discord channel hinted at possible stale LLDP neighbour data, then @adama provided this, which doesn't narrow it down much.

adama — Today at 9:08 AM

it's the logic not handling a case that i can't remember the cause of at the moment needs a bit of rewriting

The common denominator appears to be target devices in the JSON that don't actually appear anywhere in the JSON... maybe.

General questions and device support can be discussed in our Discord channel, click here to join.

Please make and attach additional information about the device:

• full snmp dump from device:

  snmpwalk -v2c -c <community> -t 3 -Cc --hexOutputLength=0 -ObentxU <hostname> .1 > myagent.snmpwalk

  snmpwalk -v2c -c <community> -t 3 -Cc --hexOutputLength=0 -ObentxU <hostname> .1.3.6.1.4.1 >> myagent.snmpwalk

  If device not support SNMP version 2c, replace -v2c with -v1.

• If you have problems with discovery or poller processes, please do and attach these debugs:

  ./discovery.php -d -h <device>

  ./poller.php -d -h <device>

• additionally attach device and/or vendor specific MIB files

This comment is added automatically.