Extending Ethernet Connections

Randy Calderon · ‎01-21-2016

Hello Experts,

I was wondering if anyone here in the Cisco Support Community have successfully extended an ethernet network that handles VoIP traffic. If so, I'd like to know your recommendations. I need to extend two ethernet connections by no more than 400 feet. What type of ethernet extender device did you use and what media (fiber, coax, etc.) did you use to extend the ethernet connection? What are the possible disadvantages and/or issues I might face if I extend this VoIP ethernet connection?

Thank you very much for your time,

Randy C.

Philip D'Ath · ‎01-21-2016

Being over 100m you'll need to use fibre (coax is from the dark ages). I would use switches with built in fibre ports. Then you just need to buy SFPs.

What sort of switches are you using at the moment?

Randy Calderon · ‎01-21-2016

Hello Philip,

We have one Cisco 2960-X to be used on that site and I have a Cisco 3560-E that I use in the lab. This extension is only temporary as the site is being renovated. After the construction, this extension will go away.

Is it possible to purchase fiber cables that are already pre-terminated? I've never handled fiber cables before.

Thank you for your time,

Randy

Philip D'Ath · ‎01-21-2016

This is a 120m fibre run. Possibly - but I wouldn't do it. Get a professional cabling company in, and get a proper cable put in. If this single cable fails you'll loose the whole site that has been renovated.

Because the cost of labour is high and fibre is relatively cheap, I would get a pair of fibres installed so you can form a redundant link.

As long as both switches can take SFP's, you'll need to buy SFP's as well to plug the fibre into.

Randy Calderon · ‎01-21-2016

I was looking at Table 1 of http://www.cisco.com/c/en/us/products/collateral/interfaces-modules/gigabit-ethernet-gbic-sfp-modules/product_data_sheet0900aecd8033f885.html and I got thrown off and confused about multimode fiber limitation. Thanks for clarifying that.

I've reached out to a cabling company and asked to give me a quote for this job. I plan to use a GLC-SX-MM SFPs for both switches. For the Cisco 3560-E, I will use a "TwinGig Converter Module" together with the SFP. Does this seem like a sound game plan to you?

Thanks again,

Randy C.

Philip D'Ath · ‎01-22-2016

FDDI grade fibre is from the dark ages. You would only find it at old sites. These days you should only be installing OM3 or OM4 fibre.

Philip D'Ath · ‎01-22-2016

It would be great if you could rate my answer and mark it as correct if you think it has helped you. :-)

Leo Laohoo · ‎01-21-2016

400 feet would mean about 121 metres. This distance is about the borderline to support multi-mode fibre (OM3). I'd go for multi-mode fibre because:

1. Multi-mode fibre optic cable is CHEAPER than single-mode; and

2. Multi-mode SFP/SFP+ is half the cost of single-mode variety.

Philip D'Ath · ‎01-21-2016

Seriously, OM3 is no where near its limit at 121m at Gigabit speeds.

On the 2960-X you would use 1000BASE-SX.

http://www.cisco.com/c/en/us/products/collateral/interfaces-modules/gigabit-ethernet-gbic-sfp-modules/product_data_sheet0900aecd8033f885.html

The 1000BASE-SX SFP, compatible with the IEEE 802.3z 1000BASE-SX standard, operates on legacy 50 μm multimode fiber links up to 550 m

Joseph W. Doherty · ‎01-25-2016

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An alternative to fiber, is to use to copper cables, each 200 feet, and join them with an inexpensive (dumb) switch.

I only mention this, as in a later post, you say this is for a temporary setup.