How do I connect two HP switches via fiber optic using the SFP ports.

Posted on 2012-04-13
Last Modified: 2012-04-13
Hello Experts,

I have two projects where I am linking two buildings for data. I will be using pre-terminated 62.5 multimode fiber. I was thinking of going with SC connectors because this seems to be the standard lately but I can use another type if needed.

I will be using HP Layer2 switches. Most likely I will be using model HP 2520-24G-POE. I can use different models if needed but would like to keep my cost around $1,500/switch.

I've always seen SFP links on my switches and know there for connecting gig fiber or copper but I have no clue how to accomplish this. Is there just a  cable I need to purchase?

So something like this:
(MDF Switch) SFP port ---> fiber patch cord ---> wall mount termination box to adapter panel ---> preterm fiber ---> wall mount termination box to adapter panel ---> fiber patch cord ---> (IDF Switch) SFP port.

What do I need and how do I connect my fiber to the switch. Would I want to use a certain connector for the fiber such as SC or LC?

In the past I've used media converters but if possible I would like to get rid of this point of failure.
Question by:mlsbraves

Accepted Solution

RKinsp earned 250 total points
ID: 37844491
Check out the accessories tab:

the SFP for the 2520 (details below) is LC connector. You can connect the cable directly although it is more common to do the whole patch-cord -> wall termination, makes it easier for cabling changes. You'll see that HP also offers patch-cords (LC-LC), although you probably get a better price from your cabling provider.

HP X121 1G SFP LC SX Transceiver (J4858C)
A small form-factor pluggable (SFP) Gigabit SX transceiver that provides a full-duplex Gigabit solution up to 550 m on multimode fiber.

1 LC 1000BASE-SX port
Duplex: full only
Connector type: LC
Wavelength: 850 nm
Physical characteristics
Dimensions: 2.24(d) x 0.54(w) x 0.48(h) in. (5.69 x 1.37 x 1.22 cm)
Weight: 0.04 lb. (0.02 kg)
Transceiver form factor: SFP

Expert Comment

ID: 37844501
Also note that according to the transceiver details, you will get a shorter range with a 62.5 mm fiber - up to 275 meters.

Cable type:
62.5/125 µm or 50/125 µm (core/cladding) diameter, graded-index, low metal content, multimode fiber optic, complying with ITU-T G.651 and ISO/IEC 793-2 Type A1b or A1a, respectively
Maximum distance:

2-220m with 62.5 µm core diameter, 160 MHz*km bandwidth
2-275m with 62.5 µm core diameter, 200 MHz*km bandwidth
2-500m with 50 µm core diameter, 400 MHz*km bandwidth
2-550m with 50 µm core diameter, 500 MHz*km bandwidth

Assisted Solution

awaggoner earned 250 total points
ID: 37844543
The switches do not normally come with the fiber tranceivers.  Your switch comes with what they call 4 dual-personality ports.  You will see the standard RJ-45 port, and to the right of it you will see an empty slot.  This slot will be for the SFP transceiver.  You can not use both the RJ-45 and the corresponding SFP slots at the same time.  However, you can mix and match.  You could have 2 fiber and 2 copper f you want, for example.

The SFP transceivers are purchased separately.  It looks like you will need the HP X121 1G SFP LC SX Transceiver (MFG#J4858C).  It retails for $348each.  It is multimode and has an LC connector.  Here is the cabling distance specs for this transceiver: 2-220 m (62.5 µm core diameter, 160 MHz*km bandwidth), 2-275 m (62.5 µm core diameter, 200 MHz*km bandwidth), 2-500 m (50 µm core diameter, 400 MHz*km bandwidth), 2-550 m (50 µm core diameter, 500 MHz*km bandwidth)

You could have about any connectors on your patch panel you like.  You just need to make sure your jumper between your switch (LC) and your patch panel is correct.

There isn't much difference between the various types of connectors.  The loss is pretty negligible as long as you don't try to use a bunch of jumpers.  Personally, I like the ST connectors.  They are easy to use, and easy to clean.  The problem is they take up a lot more room than the LC or SC connectors.  But if you don't have a very high density, then it doesn't matter.  ST connectors twist in, SC and LC connectors clip in.
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LVL 17

Expert Comment

ID: 37844749
If the cable between buildings is longer than the J4858C allow , you should use J4859C (up to max 550m).
They are expensive and you MUST use org. HP-labeled in HP-switch

Expert Comment

ID: 37844772
The J4859C can do either single-mode or multi-mode fiber.  That is one reason is is expensive.  If you go with this, I would suggest using single mode fiber to begin with.  Single mode fiber is generally less expensive than multi mode fiber since it is easier to manufacture.

Author Comment

ID: 37844989
Thanks for all the feedback.

So, to use the SFP ports you need to buy whats called a "transceiver" correct? Each transceiver is unique to that model of switch correct? Do the transceivers just plug into the SFP ports? The picture of the transceiver looks more like a card where on the switch theirs 4 small ports.  

My fiber runs are no longer(not including patch cords) than 475 feet or 144.78 meters. So in this situation the HP X121 1G SFP LC SX Transceiver (J4858C) would be my best choice?

Expert Comment

ID: 37845001
The SFP transceivers are usually the same for various models of switches.

The transceiver should slide right into the port on your switch.

The J4858C would be the correct choice for your needs.

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