Cable Trace (frontport to frontport) not available

Environment

• Python version: 3.9.1
• NetBox version: v2.10.4

Steps to Reproduce

To create two devices, do the following:

1. Create a device Role: “Role”
2. Create a manufactorer: “Cisco”
3. Create a Device type: manufactorer: Cisco, Model: TestModel, Height: 2
4. Create two sites: Name: TestSite1/TestSite2
5. Create one device on each site. Name: TestDevice1/TestDevice2 Site: TestSite1/TestSite2 Device type: Cisco TestModel Role: Role
6. Create one rear port on each of the two devices: Device: TestDevice1/TestDevice2 Name: rear1/rear2 Type: SC Positions: 1
7. Create one front port on each of the two devices, connected to the rear ports created in step 6. Device: TestDevice1/TestDevice2 Name: front1/front2 Type: SC Rear Port: rear1/rear2
8. Finally, connect the two front ports by clicking “connect – Front Port – connect”, then creating the cable between the two. Image to illustrate:

Expected Behavior

Showing a trace between TestDevice1 and TestDevice2 with a cable in between.

Observed Behavior

When trace is clicked, nothing appears. Here is the trace view:

Additional Infromation

• I have developed some plugins, but they are disabled.
• Initially, I observed that most of the trace where broken. The majority where fixed by running the command: python manage.py trace_paths.

Thank you for your time!

[jeremystretch]

This behavior is expected as front and rear ports are pass-through ports. Cable traces are created only when there is at least one non-pass-through endpoint, as all traces must define an origin point. Once you connect an endpoint (interface, console port, etc.) you’ll be able to trace the path.

[dreng]

I can confirm this issue and just want to add that the trace will be successful if “end devices” are connected (via interface). I’m not sure since when it is broken but I’m pretty sure that it has been functional before. My guess is that it’s broken since v2.10. Maybe related to #4900 ?