SPF / SPF+ connections can be finicky, hyper-sensitive to settings or physical connection issues. If you don’t have the ports on both devices set to the same settings, you’re probably dropping down to the “lowest common denominator” speed that they can negotiate. It can be a painful trial-and-error experience to get them working correctly.
It’s incredibly irritating, because you expect them to behave like an Ethernet connection and “just work”, but SPF is unfortunately not as mature or common as Ethernet, and so it’s just something where you have to deal with the pain, hopefully only once during setup.
Given that you’re able to get correct speeds with the Ubiquiti cable, but not the generic cable, it does suggest the issue is the cable. But it might just be that the cable’s active components aren’t set to the right settings, or need a slightly different config in the Unifi interface. If you don’t mind more trial-and-error, you might eventually get it to work. Whether that’s worth the effort…
Maybe I am just an old man, but I don’t endorse cables with actual, user configurable “Settings”. The endpoints should come to an agreement between themselves.
We certainly don’t need additional points of failure in our toolchains.
Ironically enough, I had a download that was going slow on a computer (in reality it was not my system, but their servers), so did some speeds tests across a couple of different computers. My upload speed is always rock solid, but download speeds not so much from that switch connected using SPF+/DAC. Download speed really varies from minute to minute (still good, but not the full 2gb). I would say that could be because of security settings, or the network being busy, but the speed tests directly form the gateway are always a full 2 Gb up/down.
After doing some reading, anything over 5-7 meters on a DAC cable might cause some issues. My original cable, that is just a bit short, is 5 meters. My new cables are 10 meters. So it might be a cable length thing.
Looking at port settings, I don’t see a lot I change, but it’s all Greek to me. I need to do some reading on that.
I think I need to find another way of wiring my network, which is going to cost me money. I could get SPF+ injectors so I could use ethernet cables (I am still not sure what the drawback of them is). Or I could get another switch with 2.5 GbE ports to connect directly below the Dream Machine, and then run an ethernet cable out to my office switch. Or I could try to find a 6 meter DAC cable.
As fiber gains popularity, it’s a bit surprising to me how difficult/expensive it is to build a network that can support it. The all in one home routers are lucky to get more than two 2.5 GbE ports, and Ubiquiti doesn’t really have a lot either in their prosumer equipment.
Well, it’s more that the ports have configurable settings, for speed, etc., rather than the cables. And in theory SPF/SPF+ should auto-negotiate.
An SPF[+] port is a port designed to install a media adapter into, and then you put (standard?) cables between the adapter ports. For example, you can install optical media adapters into your SPF ports, and string an optical cable between them. Or you can install Ethernet media adapters, and use an Ethernet cable. Etc.
It’s very flexible, but it’s not a consumer-oriented connection. Very much the opposite, they originated in the world of data centers for high-speed optical connections between server racks, etc. When they were designed, they were designed for devices that would only be used by professionals in commercial settings. They are not Ethernet.
The “all in one” adapters with attached cables are a nod to consumer-style usage, like Ethernet, making it easier, where by “easier” we mean no longer requires advanced network device management training. But you can still get into trouble.
It’s definitely possible to make SPF[+] connections “just work”, but you should probably stick with one vendor for everything, unless you know what you’re doing, or have done the research to verify that your chosen solution is verified by someone else who does.
Quick update for folks who might be intrigued by UniFi, but want to start without, uh, breaking the bank. Chris Sherwood over at Crosstalk Solutions published the perfect video for you earlier this month: UniFi Basics: Start the Right Way Without Breaking the Bank!
Really good explanation of two possible “starting points”, including a strong recommendation for the “best” starter system for UniFi beginners.
EDIT: A second video in this “UniFi Basics 2024” series just dropped, covering actually setting up a new UniFi system, using the starter system described in the earlier video.
I’m not sure I’d use it as my step-by-step script directly; the video shows all the required steps, some optional ones, and also tours some features “to be set up later”. That might be overwhelming as a to-do list. But it’s a great tour of the process, plus some additional capabilities of a UniFi-based network. You can create a customized run list of configuration tasks from it, and work from that. (Keeping a detailed log of how you configured your network, or any complex technical system, is a great idea. You’re helping Future You, when you need to go back later and make changes, or do it again, etc.)
I love me Unifi system. I broke the bank, and continue to do so (need more 2.5 GbE switches!), but the control and power of the system is game changing for me. VLANs, geoblocking, DNS blocking, and just being able to see what is going on is great.
I geoblocked a bunch of countries that have more questionable internet trustworthiness, such as China. Turns out my cat’s auto-feeder needs to call China once ever 2 weeks or its camera stops working (thankfully it will still function otherwise). I can also see what all these little IoT devices are doing.
