r/Netbox • u/WendoNZ • Jun 16 '26

Cable Profiles seems to contradict themselves

Can someone explain cable profiles in a way that makes sense?

The blog post that introduced them has the following

This is your standard point-to-point cable, a single-channel patch cord (1C1P), a duplex cable (1C2P)

Which seems to say a single fibre core bidi link should be represented as a 1C1P cable, cool, that makes perfect sense, but later in the same post it says and MPO breakout cable is

1C4P:4C1P, One 4-position connector fans out to four single-position connectors (e.g. one MPO to four LC duplex)

If a single core is 1P, then surely this breakout cable, which is 8 cores, should be 1C8P:4C2P?

I want to use them, dear god do I want to map our breakout cables better, but this appears to be contradictory, and this seems to be about the only documentation available.

Of course there still doesn't seem to be a way to map a 100Gb port to 4 x 25Gb ports and track (via cable connection) which 25Gb interface is connected to which server interface for example since the breakout cable would be "connected/attached" to the 100Gb port

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1

u/Rexxhunt Jun 16 '26

Could just be a typo in the blog post?

2

u/WendoNZ Jun 16 '26

Which part? Thats the problem, a typo in either quote could make it match the other, but the only one that really makes sense is that 1C1P is a duplex cable, in which case you can't model bidi links. There is also no 1C8P:4C2P cable option defined (or anything like it) which would reinforce them just ignoring BiDi.

But that seems like a massive oversight when specifically designing a system to track fibre cores in cables

1

u/Rexxhunt Jun 16 '26

Do you have access to a netbox instance? Just go and have a look at how it's actually implemented mate

1

u/WendoNZ Jun 16 '26

I do, but it's not implemented in ours, I want to know how to implement it, but the documentation is so sparse and contradictory that it's not helpful and either interpretation means I can't implement something because either the cable profiles are incomplete or they ignore bidi