Split port on qfsp-lc cable on supported interface

[Valantin]

NetBox version

v4.4.5

Feature type

Other

Proposed functionality

permit to create a non virtual child port to connect device using switch functionality to crate 4 splitted port on a qsfp port.

Use case

We have a Huwei CE16816 ith a cel36lqsfd-g anc cel36cqsfd-g port card.
We use 1 40GE port to create 4 10GE port using a mpo split cable. in this way we use 8 fiber to connect 4 different LC duplex port, same use of a 100GE port ot create 4 25GE port.

Database changes

No response

External dependencies

No response

[pheus]

Thanks for opening this!

If I’m understanding your request correctly, I think the cabling/tracing side of this may already be covered in NetBox v4.5 via Cable Profiles (see #20788). Could you take a quick look on v4.5+ and let us know if it solves your use case?

[Valantin]

ASAP try with the suggested feature but after a fast read I think is a different situation.

I've a single qsfp+ port on the switch, physical port 40GE0/0/0 with a mpo split cable.

So I can create 4 splitted sub interface 40GE0/0/0:[1-4] to use eatch one couple to manage a 10GE dedicated interface.

I've created a patchpanel with rearport for the mpo side and frontport for the LC side.

But if I connect the interface 40GE to the rear port how I can manage the 10GE interface?

Probably I can create two type of transceiver device, one with 1 40GE and one with 4 10GE interface, but I think was better add a way to create splitted interface in the same way I can create virtual interface and permit to map the mpo correct wire automatically to the splitted interface.

[Valantin]

I've reread the linked feature, for what I'm understud it is related to the cable, but no effect on the interface side.

As I said in my configuration I've create 4 splitted interface in my switch, parenting the physica interface, and each of thes splitted interface use a couple of a MPO-8 cable
so I want to connecto LC-1:12 to 40GE0/0/0:1, LC-2:11 to 40GE0/0/0:2, LC-3:10 to 40GE0/0/0:3 and LC-4:9 to 40GE0/0/0:4
than connect LC-2:11 to server1 eth0, LC-4:9 to server2 eth0 and follow the connection from server1->eth0->patchpanel LCtoMPO->40GE0/0/0->40GE0/0/0:2

[Valantin]

@jeremystretch I’m not sure why this was moved to a discussion. I’d appreciate some guidance on how to properly submit this feature request.

Proposed functionality

Native support for split (breakout) interfaces.

Use Case

40GBASE-SR4 and 100GBASE-SR4 (see IEEE 802.3bm) are based on four physical lanes and are commonly deployed in breakout mode:
• 40G → 4×10G
• 100G → 4×25G

Using MPO-8/MPO-12 breakout cables, a single QSFP+/QSFP28 port is split into four independent duplex LC connections. Each lane operates as an independent interface with its own configuration and remote device.

This is a very common deployment model in modern data centers.

NetBox allows modeling breakout cables (ref. #20788), but there is no native way to:
• Represent a single physical interface as split into multiple logical interfaces
• Maintain a parent/child relationship between the original port and the split interfaces
• Prevent using the parent interface when it is split
• Independently cable each split interface

Currently this requires workarounds and manual modeling, which breaks the structural relationship between the physical port and its breakout lanes.

Database changes

Expected Behavior
• A physical interface (e.g., QSFP+-SR4 / QSFP28-SR4) can be marked as “split”.
• When split, it generates 4 child interfaces.
• Each child can be independently cabled and configured.
• The parent interface becomes non-usable while in split mode.

We use breakout extensively across 600+ devices in our data center environment. Native modeling support would significantly improve accuracy and reduce manual inconsistencies.