Allow a cable to be connected to multiple devices

[cpmills1975]

NetBox version

v3.6.3

Feature type

Change to existing functionality

Proposed functionality

I can see that it is possible to connect a cable from the A end to multiple components on a single B end device, but it does not appear to be possible to model a cable that is connected to a single component on multiple B end devices.

Use case

Break-out cables are frequently used to 'break out' a multi-channeled interface in to separate channels, sometimes across several devices. e.g. there is no reason why a 40G QSFP interface cannot be connected to a single 10G SFP interface on four different downstream devices.

I've managed to model this by traversing a patch panel with four front ports and four rear ports such that the four downstream devices have one-to-one cables going in to the rear port and the QSFP is connected to the four front ports on the patch panel, but I cannot connect the QSFP port directly to the four SFP ports.

Database changes

Presumably none - the cable end point references a single component, the fact those components can't be on different devices feels like a UI issue.

External dependencies

None

[craized]

If I'm understanding correctly, I second this. I've been waiting for quite a while for the fixes that came with #13337 and am excited to see them released.

The above fix CAN cover this use case, however it was determined that it wasn't part of the bug fix, but rather a feature request (as stated here: https://github.com/netbox-community/netbox/pull/13337/files#r1295124404).

On my own instance, I've resolved this to test by commenting out the following lines https://github.com/netbox-community/netbox/blob/develop/netbox/dcim/models/cables.py#L521-L525. I assume this is a naive implementation and it may break something else.

I'm including the trace from my modeled span both as a PoC and to clarify the use case. Note that this is only half of the cable trace, and the other side would be the exact mirror.

[PieterL75]

Isn't his already possible ??
I tried it on the demo instance, and there you can connect one port to multiple devices.

Steps

• create a new connection
• select a device, and an interface
• the interface becomes a 'label'
• select another device, and an interface
• a second interface is show in the list

I do agree that the EDIT UI is not very intuitive nor showing enough details for these kind of cables.
The cable view does show all the devices and interfaces :

[craized]

Interfaces connected to multiple devices are fine (and have been since multi termination was introduced iirc). The failure mode comes from connecting to front ports on a device that map to more than one rear port, which in turn connect to multiple devices.

…

On Wed, Oct 4, 2023, 1:56 AM PieterL75 ***@***.***> wrote: Isn't his already possible ?? I tried it on the demo instance, and there you can connect one port to multiple devices. [image: image] <https://user-images.githubusercontent.com/74899468/272518176-6bf1b31b-07c9-465c-9139-b1c98e90f2f4.png> Steps - create a new connection - select a device, and an interface - the interface becomes a 'label' - select another device, and an interface - a second interface is show in the list [image: image] <https://user-images.githubusercontent.com/74899468/272518614-bb346fdf-8d65-48dc-8c92-a8fe9a391ddd.png> I do agree that the EDIT UI is not very intuitive nor showing enough details for these kind of cables. The cable view does show all the devices and interfaces : [image: image] <https://user-images.githubusercontent.com/74899468/272518917-7d9f980d-12e0-4327-9c5f-ce95c9f658b5.png> — Reply to this email directly, view it on GitHub <#13923 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAD2A2RHZMDIQS3Z6KA7Z3DX5UQE7AVCNFSM6AAAAAA5KCISSCVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTONBWGQZTKMJQGQ> . You are receiving this because you commented.Message ID: ***@***.***>

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[jeremystretch]

Closing this out as the requested functionality already exists, per @PieterL75's comment above. If there's some other requirement not surfaced here, please submit a new FR detailing it.