Doubt about how SFP/SFP+ works

[KLMR]

I'm guilty to be trapped in ubiquiti world.
In an attempt to improve a segment of my network I bought USW-Enterprise-8-PoE-EU and three SFP+ UACC-CM-RJ45-MG which are 10/5/2.5/1 copper modules.

I've been told by the technical service of ubiquiti that those "enterprise" switches don't allow 5/2.5 speeds, only 10/1.
So USW-Enterprise-8-PoE-EU and UACC-CM-RJ45-MG will only work at 10 or 1 Gbit. Is that possible? Has anyone been able to run it at 5 gbit on those switches?

I've read your article comparing different SFP+ modules, and, AFAIK, those capabilities are module-wise not switch-wise. On the other side I know the world of SFP is a little messy but MSA exists. The modules are from the same brand as the switch. The brand has few "enterprise" switches in his catalogue
On the other hand...
There is no compatibility chart of accesories for the switch nor a list of compatible switches for the SFP module.
Their documentation in the specifications and compatibility area is scarse and mostly outdated.

 

[tinfoil3d]

Datasheet is very scarce, and while it feels "normal" for SFP+ to be either 1 or 10 gbe, there's gotta be a compatible ubiquiti product that takes these. According to common sense.
Interesting. Why don't you ask the said tech person for which switches are compatible then? And return the modules if you can't use them.

 

[KLMR]

The fun part of ubiquiti shop in Europe is customer pays for return costs. Which would be fine IF there wasn't one address for the whole European Union (up North), they also ask for a tracking number.
In my case, if I use a trusty courier, returning something usually costs more than the object.

That SFP module is specifical for 10/5/2.5/1, they have another model limited to 10/1.

 

[sko]

IIRC there are modules that will report a 10G link to the switch but can negotiate the actual link at lower speeds.
Maybe have a look at fs.com for such transceivers or just ask their support - they are very helpful and fast to respond.


And yes, the ubiquity support is absolute crap just as their products (which are "prosumer" grade at best but far from enterprise...). I also had to deal with them a few times over the years and there's nothing worse except maybe the Deutsche Telekom...

 

[tinfoil3d]

Yeah, it may actually just work, because, hey, sfp+ will happily downclock to sfp speed of 1gbit. don't see any reason it not being able to downclock to 2.5 or 5g. while still reporting 10gbe to host.

 

[Railgun]

The PHY needs to support it. If not, the module doesn't matter. You can use a module that will do all rates, but it will only operate at 1 or 10.

 

[KLMR]

I've been in contact with unifi because of this in the past month. About 8 mails from each side. Escalated twice. No clear answer yet. They aren't signing the mails anymore (with names).

As soon as I have a clear official answer I'll publish it here for the record.

 

[Railgun]

It won’t.

 

[CyklonDX]

each sfp module has its own set of signal clock; (in your case it may only allow 1Gig or 10Gig) and i don't see any issue - there's no clock-gen on those modules, as it would be more expensive, and another chip on sfp itself that would be required.
*(you could potentially reprogram the sfp modules, with some wizardly - but it may no longer be valid by cert installed for your ubiquiti cert on the sfp module)

most of those sfp modules were made no1 has thought anyone would use 2.5-5Gbit - those "standards" came out much later down the road.

The switch has likely outdated firmware that does not understand standards of 2.5-5Gbit - it still needs proper clock-rate for the sfp module (in fact you will find that almost none of enterprise 10Gig+ have support for those.)