Network setup between buildings

Benderama used Ask the Experts™

I need some input about a network setup we are going to deploy next year,
We are building a small campus with 3 buildings about 30meters (100ft) apart, one main building and 2 smaller buildings.
The main building has about 45 LAN  (RJ45) connections and the smaller building have 20 each.
On the main site we have the WAN connection, servers, NAS devices (backup). The rest of the network contain client computers and VOIP phones. We don’t have that much traffic on the LAN but I want to back-up the servers (about 1TB/night) to a NAS in one of the smaller buildings to have a “free” cloud back-up solution using VEEAM backup & replication.

We have:   1 x 48 Cisco Catalyst 2960-X Series switch (WS-C2960X-48LPS-L) SWITCH (Main building)
                    2 x 24 Cisco Catalyst 2960-X Series switch (WS-C2960X-24PS-L) SWITCH (Smaller buildings)

I've been asked to tell the building company what cables to use and how to deploy them.
First they suggested to use 4 UTP cables between each building which sound to me like a really BAD solution, the second solution was to attach FTP CAT5E cables to each RJ45 outlet and pull them all to the main building.  But I don’t really like this option because of the cost of the cables and the setup.

I suggested to use 2 fiber cables from the main building to each of the sites (one to use and one as reserve in case something went wrong with the main fiber cable)
Since we have the Cisco Switches I wanted to buy 4x SPF fiber connectors and connect the 2 sites to the main building with one fiber per site. And order Multi-mode fiber cables that are already terminated so we don’t have this extra cost.

Is this a good solution? It is ok to use Multi-mode fiber instead of single-mode?
Do our Cisco switches support all this?
I’m used to working with smaller LANS and have never used fiber when I wasn’t inplace before I got there so this is kinda new ground for me.
Thank you for your opinions!
Watch Question

Do more with

Expert Office
EXPERT OFFICE® is a registered trademark of EXPERTS EXCHANGE®
Principal Software Engineer
Fiber is certainly a better solution but as long as you're pulling cable, I'd pull four or six.  Cable runs are rarely rodent-free and the need for bandwidth never decreases.  Aside from that, the cost of having professionals pull the cables will outweigh the cost of the cables.

Do not forget to specify cables sufficiently overlength for one meter strain relief loops at each end.  Expansion and contraction is an issue where cable runs are not heated to room temperature.  Further, generous cable lengths don't cause problems but sometimes do solve them.
Distinguished Expert 2018
The solution you suggested is actually the best one. It leaves you in a better long term position AND it is something far less prone to be affected by the elements (as well as rodents as Dr. Klahn pointed out). Had the buildings actually been bigger (and having far more connections than what you've mentioned), then I would've thrown in the suggestion of also looking at fiber to connect the floors.
Distinguished Expert 2018
It is ok to use Multi-mode fiber instead of single-mode?
Yes - for distances < 550m (OM3 or OM4).
Do our Cisco switches support all this?

Why not use both fibers between buildings? That way you will reduce size of STP domain.
If you will not use both fibers, but daisy-chain switches in small building, less expensive solution would be to use 2 x GLC-T and copper cable between 24 port switches.


Thank you for the information

Do more with

Expert Office
Submit tech questions to Ask the Experts™ at any time to receive solutions, advice, and new ideas from leading industry professionals.

Start 7-Day Free Trial