Fibre into a switch

[Sonic007]

I have a fibre connection coming into a server cabinet that goes into a media Convertor and back to etherrnet.

Instread of upgrading the 10/100 Media converter to Gigabit, I have a gigabit switch with two SFP ports.

 

What do I need to connect up and do I just go directly into the switch and all should be fine?

 

 

Thanks all.

[caffrey]

Look for a SFP Module that is compatible with your switch. Do you have a fibre patch panel ?

[3s-gtech]

Once you have the SFP installed, you then need a patch lead that will connect the fibre to that SFP. This will depend on what ends have been put on the fibre, but the SFP will usually be LC and the patch panel often SC (but can differ). You'll also need to make sure it has the same optical spec (e.g. OM5) - usually 50/125 with newer runs.

[Davit2005]

As long as the SFP is compatible with the switch, fibre is compatible with the sfp and you have not set specific duplex/speed settings on the port then yes (check to see if other end is matched). Just make sure any vlans are copied from the copper port to the sfp port on the switch should be fine.

 

I've seen switches before which lose their vlan settings on removal of SFPs so one to look out for.

[Norphy]

Yes, you just need an SFP or SFP+ module, depending on the speed of your uplink. Depending on the type of termination your fibre has, you may also need a new patch lead as SFP modules use LC connections and ST and SC terminations on patch panels aren't that unusual.

 

https://www.cablemonkey.co.uk/366-lc-fibre-connectors-adapters

[Michael]

Chances are your fibre patch lead has an ST or SC connection going into the Media Converter.

 

You'll need to identify the fibre type, as it varies a lot. As a rough guide -

 

OM1 = Grey 62.5/125

OM2 = Orange 50/125 or 62.5/125

OM3 = Green 50/125

OM4 = Green 50/125

 

The SFP or SFP+ module will need an LC end patch lead, so it could either be ST > LC or SC > LC as common examples. You of course need to do this both ends to operate at 1Gbps and beyond.

[Norphy]

Chances are your fibre patch lead has an ST or SC connection going into the Media Converter.

 

You'll need to identify the fibre type, as it varies a lot. As a rough guide -

 

OM1 = Grey 62.5/125

OM2 = Orange 50/125 or 62.5/125

OM3 = Green 50/125

OM4 = Green 50/125

 

The SFP or SFP+ module will need an LC end patch lead, so it could either be ST > LC or SC > LC as common examples. You of course need to do this both ends to operate at 1Gbps and beyond.

 

In my experience, the colour guides are unhelpful at best when it comes to identifying fibre. Guides like that are accurate until they aren't, if you see what I mean. I have OM3 patch leads which are orange and a sort of blue/cyan colour but I've never seen a green one before. The only real way to be sure is to look at the covering on the fibre and see if the fibre type is printed on it.

[Michael]

In my experience, the colour guides are unhelpful at best when it comes to identifying fibre. Guides like that are accurate until they aren't, if you see what I mean. I have OM3 patch leads which are orange and a sort of blue/cyan colour but I've never seen a green one before. The only real way to be sure is to look at the covering on the fibre and see if the fibre type is printed on it.

 

I agree, hence why I definitely said rough It can be an indication, but isn't guaranteed.

 

Hopefully in future it'll be less of an issue, as at least all new multi-mode fibre is 50/125; more so the equipment either end being the limitation rather than the fibre itself.

[Sonic007]

Thanks all for your replies.

 

Here is a picture of the switch and then the current 10/100 Media Convertor with the Fibre plugged in.

[localzuk]

Thanks all for your replies.

 

Here is a picture of the switch and then the current 10/100 Media Convertor with the Fibre plugged in.

[ATTACH=CONFIG]62070[/ATTACH][ATTACH=CONFIG]62071[/ATTACH]

 

Do you have a photo of the other end of the yellow fibre lead at the fibre-patch panel end?

[3s-gtech]

Your fibre has SC ends on it, and the switch should take an SFP (called mini GBIC in the past).

 

EDIT: your patch lead has SC ends, your patch panel has ST. ST was more often used with OM1 and pre-OM1 but I've seen it used with OM3.

Edited June 8, 2021 by 3s-gtech

[localzuk]

So, this is what you'd want for the SFP - https://www.amazon.co.uk/NETGEAR-ProSAFE-1000BASE-SX-Module-AGM731F/dp/B0000BVYTW (you could likely use a compatible one like this https://www.amazon.co.uk/10Gtek-Multimode-Transceiver-1000Base-SX-Connector/dp/B01C6P0KX8/ but YMMV).

 

Without seeing the other end of the fibre patch lead we can't assume what connectors it has either. I had SC to ST leads when I arrived at one school. Now running ST to LC. The other thing to do is look on the cable itself and look for any markings regarding cable type - an OM number or 50/125 etc...

[Sonic007]

This is the other end.

[Norphy]

Those are ST connections - to use an SFP module in a switch you will need an ST to LC patch cable.

 

Yellow sometimes means it's single mode fibre but I doubt that's the case there. Look on the cable and see if there's any printing - something like "50/125 OM3" or similar

[localzuk]

OK, so you'll need an ST to LC cable. The last thing to figure out is cable type. Is there anything printed on the yellow cable, or if not, can you see the main fibre cable anywhere and see if anything is written on that? My guess is it may be OM1 based on the age, but I wouldn't like to guess really.

[Oaktech]

My favourite store for this is fs.com cheap, good stuff, delivery times acceptable for being in china and good sales support (I ordered 3 of one type SFP and 1 of another by accident and they paused my order and called me within an hour to check that I had meant to do it!)

[Michael]

SC to ST then and looking at the age of the patch panels, I'd hesitate and guess it's OM1 or OM2.

[Sonic007]

Thankyou everyone.

 

The school is indeed running old patch panels. When I inherited this place 2 years ago I have been progressively removing random 10/100 switches stuffed in ceilings, old redundant hardware, and trying to get the whole network on gigabit hardware.

Patch panels are only CAT5E but will have to do for the time being.

 

I had a look at the yellow fibre cables. Not much info really. Only thing printed on them is "SCST50DYE2 fibre optic cable".

 

Again, thanks to all for your help. Much appreciated.

[localzuk]

I'd guess from that model name, its probably a 50/125 type cable (going by the 50), so probably OM2?

[Norphy]

I wouldn't worry too much about the Cat5e cable you've got. Cat5e is still good for gigabit speeds up to distances of 100m so unless you've got areas which are particularly electrically noisy or are looking to use 10GbaseT over longer distances, it's fine.

[localzuk]

Indeed. Cat5e is fine. We've got it in all of our schools and nurseries and cannot see any benefit to replacing it when it works.

[Michael]

I wouldn't worry too much about the Cat5e cable you've got. Cat5e is still good for gigabit speeds up to distances of 100m so unless you've got areas which are particularly electrically noisy or are looking to use 10GbaseT over longer distances, it's fine.

 

Apparently CAT5e 'can' do 2.5Gbps with a supporting switch up to 100m and CAT6 5Gbps up to 100m. Whether or not these standards will be adopted by enterprise IT remains to be seen!

 

Multi-Gig ports on high end routers will soon start becoming the norm, labelled as 5G/2.5G/1G.