How to Choose a Fibre Switch?

Do you have some experiences about choosing a very right Fibre Switch for your network deployment? Or you had set up a better network with a good Fibre Switch?

If YES, welcome to share with us here!

In this article, we’d like to share a discussion of selecting a Fibre Switch from some friends in the Cisco Support Community.

Choosing a Fibre Switch

 The Problem from A: “I’m planning a large network deployment and I need a 10Gb-Fibre switch to connect the distribution switches in a Metropolitan Area Network to the Datacenter. I need a high speed backbone from each building to the Datacenter through this Core switch but I haven’t had any luck finding the right equipment.

Could you please suggest Cisco equipment that will suit my needs, or recommend alternative methods/devices?

EDIT: the scenario is a campus type setup. 10 separate buildings, between 50 and 600 meters away, connecting centrally to a Datacenter and NOC. All up at least 12 ports. The goal is to have high-speed connections to all buildings, preferably 10GbE, using Optic Fiber for the distance. So far I’m hoping for an L3 core switch with SFP+ ports.”

Some Questions and Suggestions from B to A’s Problem:  What type of fiber do you have in place? Single mode or multimode. That will tell us whether or not you can get 10 Gbps across the longer distance.

Assuming single mode, you can use SFP-10G-LR-S transceivers for up to 10 km. With multimode you are limited to 400m (on OM4 rated fiber) using the SFP-10G-SR-S.

As far as switches, any modern Cisco switch with SFP+ slots will support those transceivers. See the Catalyst 2k and 3k series (i.e 2960X, 3560X, 3650, 3850 etc.).

For the main site where you are bringing in connection from 10 buildings, you will need a switch with more than a couple of SFP+ ports. There I would recommend choosing from Catalyst 3850 (WS-C3850-12XS for example or -24XS or -48XS versions for more ports), Catalyst 4500X (WS-C4500X-16SFP+, also available in 32 port version and either model can add an 8 port expansion module).

Cisco Catalyst 3850 Series Switches-Data Sheet, Updating

Cisco Catalyst 4500-X Series Fixed 10 Gigabit Ethernet Aggregation Switch Data Sheet-Updating

The 3850 switches can be stacked (except the 48 port all-SFP model), making adding in redundancy quite simple. The 4500X requires configuration of a Virtual Switching System (VSS) pair across two switches for redundancy. Either way ends up presenting a single control plane for configuration. (i.e., one configuration to manage)

If you’re not well-versed enough in Cisco to be familiar with the basic switching offerings, I would not advise the Nexus switches. NX-OS is a bit different than IOS operating system and the features of the Nexus switches are aligned more with data center use cases than enterprise core. That said, they are perfectly capable for most uses – they just require a bit different configuration.

Redundancy among Nexus switches requires use of virtual Portchannel (vPC), a technology that has more aspects than can be covered here.”

A’s Problems Added here:We’re preparing a new install with Fiber running underground purely because of the distance issue. Unfortunately I have no experience with Fiber technology so this has been quite a steep learning curve.

Unless we daisy-chain some of the buildings we may have to resort to 10GBASE-LR for them. Aside from the cost difference between 10GBASE-LR and 10GBASE-SR, is there anything I should be concerned about?

The main problem is that I’m familiar with the more common L2 and L3 switches with RJ45 access ports and SFP uplink ports, but I “think” I’m looking for an all-SFP switch for this core. As I said, not really my field.

Will the 3850 or the 4500 series’ work for this? “

The Solution from B again: The LR transceiver type requires single mode. SR requires multimode. Other than that, they operate the same in your switches.

If you have the option of specifying the fiber, perhaps you can get several pair of both multimode and single mode and thus have the option of using the less expensive transceivers where you can get away with it. Generally speaking the cost for new cabling is primarily in the installation – not the raw materials.

As a point of reference, list price for the two transceivers I mentioned is US$1900 vs. US$650 each for the long reach single mode vs. short reach multimode types respectively. So with 10 buildings requiring at least 20 transceivers (one at each end – two at each end if you put in redundancy), the cost can really add up.

Yes the 3850-12XS (and 24 or 48 port variations) or 4500X switch are very good choices. They are both all-SFP switches.  

More Discussions about Choosing a Fibre Switch

support 10 Gbps

The OP didn’t ask for non-blocking all 10 Gbps switch. If that’s the requirement, then yes – I agree they need to step up the model.

The 4500X I mentioned earlier is non-blocking.

“The Cisco Catalyst 4500-X Series Switch offers 800 Gbps of backplane bandwidth with up to 250 Mpps switching capacity that provides up to 40 non-blocking 10 Gigabit Ethernet ports, with 32 ports on the baseboard and 8 ports on the optional expansion module.”


When you compare costs, a WS-C3850-24XS-S (24 port IP Base) is US$22.3K list.

A comparable WS-C4500X-24X-IPB (24 port IP Base) is US$23.3K list. (Only 5% more)

The devil is in the details and you should always work with your reseller to determine the best model for your needs in your environment.

The OP didn't ask for non-blocking all 10 Gbps switch

C’s Opinion about This: “distance is low you can connect them without switches. Or if you need switch you can use Nexus 5k, 7k. In case of long distance you need DWDM equipment, please share port quantity and distance.”

A’s Response to C: I need 12 ports minimum, preferably SPF+. DWDM sounds good for a point to point, but I’m not looking for something so intense. the buildings are all between 50 meters and 600 meters away from the switch location. The purpose is a high-traffic core switch connecting each building to the Datacenter.

Cisco Nexus 7000 Series Switch might be suitable. This switch is designed for highly scalable 1/10/40/100 Gigabit Ethernet networks with a fabric architecture that scales beyond 17 terabits per second (Tbps).

Nexus 7000 is the real modular switch in the Nexus family with six versions: one 4 slot, one 9 slot, two 10 slot and two 18 slot switches. Each has different performance.

The Original Discussion from

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