My SFP is not working with GigaBlox SFP?

– Copied from customer query –

I am using two of the 6 port GigaBlox SFP to make a gigabit connection using single Mode fiber. I had a couple of olycom SFP transceivers laying around and am trying to use those.

I assume those are not compatible but i cannot find anything saying if they are 1000 BaseX or not. for power on the subsea unit I am using 48vdc. Both GigaBlox SFP work fine for devices plugged into them on the normal ports.

I just cannot get them to talk over the single mode fiber. Is there an SFP that you recommend vs the olycom? Right now, I am just bench testing with a 30m fiber to get everything talking but I will be using a 300m, 600m or 5km fiber tether once its working.

https://olycom.cn/products/1-25gbps-sfp-transceiver-single-mode-10km-reach-1310nm-tx-1550nm-rx-osbl1g20d-35-%E7%9A%84%E5%89%AF%E6%9C%AC

Thanks for the information. In theory, those should work, but I need to check.

Just to iron out some basics, can you tell me if you’ve tried these SFPs in another device, along with the fiber? Just to be sure that there isn’t an issue with the modules or fibers or anything else? Have you got other modules you’ve tried it with? And finally, what type fiber are you using?

yes, I have and they work. I think these may be Bidi SFP’s which is what I need. from what I interpret from the manual bidi may not be compatible. I really need to send and receive over a single, single mode fiber.

fiber is single singlemode LC to LC connector. the vehicle uses the fiber for comms right now and works using two of the olycom trancievers. the issue is the board in it is 4 wire. I was planning to use the botblox board for gigabit and run the vehicle board/comms through it. I have tried it on both my new 30m cable and the 600m vehicle fiber tether. neither work with the botblox board.

port 1 - 4 wire ethernet (vehicle)

port 2-5 @ 8 wire ethernet (sensors)

there is no port 6 even though its listed as a 6 port (assuming sfp is port 1 or 6)

basically, switching the sfp from the vehicle to the gigabit board.

I finally got it to work. had to turn off energy efficient ethernet on my network port and it takes it about 10 minutes to negotiate the 4 wire connection. until it does that it just connects and disconnects from the computer.

I was just about to do a full check on the SFP format and place an order for those SFPs so we could replicate in our lab.

So just to clarify, it takes 10 minutes to negotiate to a 4 wire (10/100MBASE-T) link when EEE is turned off? That doesn’t seem great either to be honest.

Yeah that seemed like a long time to me also. Im wondering if it’s a combination of the board and the laptop both trying to negotiate the connection. Im going to try to disable auto negotiation on the laptop. If it’s an 8 wire connection on the sfp chip it’s instantly connected. The 4 wire takes a long time.

Ah so the 8 wire works immediately?

So when you connect the SFP to a 1GBASE-T (8 wire) port on the computer, it’s no issue? This issue only happens when you connect the SFP to a 10/100BASE-T (4 wire) port on a computer? And you only see this when GigaBlox SFP is connected to the SFP.

Definitely seems there’s like some strange interactions going on here.

Autionegotiation in or out doesn’t seem to matter. 8 wire is instant connection. 4 wire takes a while to negotiate. Even longer if an 8 wire and 4 wire are to the same board.

Hmm. I’m wondering if this is a “switch specific” issue. Like the issue occurs when using any switch. When you tested the SFPs, what do you plug the SFPs in to?

“Even longer if an 8 wire and 4 wire are to the same board.”

Like, an 8 wire on one GigaBlox SFP port and a 4 wire on the SFP?

I noticed the same thing with the small gigabit switches I ordered last month but it wasn’t nearly this long

Super strange. I guess 100BASE-T is non-negotiable on your PC (you can’t use 1000BASE-T)?

And just to make sure I’m following… The issue doesn’t happen when…

PC (1000BASE-T, 8 wires) ↔ GigaBlox SFP copper port ↔ GigaBlox SFP SFP port ↔ SFP Module ↔ Fiber ↔ SFP Module ↔ GigaBlox SFP SFP port ↔ GigaBlox SFP copper port ↔ PC (1000BASE-T, 8 wires)

But it does happen when…

PC (100BASE-T, 4 wires) ↔ GigaBlox SFP copper port ↔ GigaBlox SFP SFP port ↔ SFP Module ↔ Fiber ↔ SFP Module ↔ GigaBlox SFP SFP port ↔ GigaBlox SFP copper port ↔ PC (1000BASE-T, 8 wires)

Right?

Yes. The issue is the rov I’m installing it in is 100base-t.

It also seems to happen

PC (100BASE-T, 4wires) ↔ GigaBlox SFP copper port ↔ GigaBlox SFP copper port ↔ PC (1000BASE-T, 8 wires)

Eventually it resolves itself and works. I just had to leave it on and walk across the shop to our bathroom and back before it worked.

Maybe this won’t happen with the rov. I was just bench testing with laptops to make sure it functioned before draining the oil from the subsea electronics bottle and installing it.

I just spoke with my CTO about this. Seems that GigaBlox SFP’s firmware does not disable EEE on the switch. This may explain some of the issue, though I can’t be sure. It feels more like this is an autonegotiation issue between the SGMII link on the SFP port and the other ports on GigaBlox SFP.

In any case, I think we’ll aim to release a firmware update to disable this. In the mean time I think we should try to replicate this issue.

Could I ask you to share the PCs you are using, if they have network cards, which network cards you use. Could you also tell me what cable you use in the 4 wire and the 8 wire cases?