What is a Network Switch?

April 21st, 2020 | Best Practices, Hardware

What is a Network Switch, and What Does It Do?

A network switch is a physical piece of equipment, usually located in your office’s server room, telecommunications closet, or network equipment rack. Network switches are active electronic devices that connect all of your building’s in-wall network cabling and permit devices to talk over your wired network. You’ll often see them in your network equipment cabinets or racks with many cables connected to ports all across their face, often 20, 40, or more cables per switch. Depending on the size of your office, the number of users, or other factors, you may have one or more network switches.

Modern network switches are programmable, which permits us to use the network switch’s features to logically isolate and segregate different types of network connections inside your building for special handling like voice, video, guest internet access, industrial control systems, network administration, and more. Modern network switches are also often used to supply low-voltage electrical power over your in-wall network cables, letting devices like telephone desk sets power on and function with just a network cable connection.

Network switches can also have modular connection options that connect them to more than just copper network cable. For example, some switches support fiber optic modules for operating at higher speeds over longer distances. Network switches are rated by their feature set, remote management capabilities, electrical power supply capacity, number and types of cabling ports they support, and the performance capacity of the switch.

As a best practice, Aldridge specifies network switch manufacturers with products that integrate with our IT management and support stack. We recognize there are many models of network switches out there, including bargain switches available. While the core function of moving data from point A to point B can be the same, there are differences in reliability and lifecycle, performance, security, flexibility, diagnostics, and management that make a higher up-front investment a more economic choice over the four to six-year lifecycle of a typical network switch.

Configuration Elements We Consider When Installing Network Switches 

  • Is this a new installation, or are we replacing an existing, older or smaller network switch? If it’s a new installation, we configure these elements below to Aldridge best practices, consistent with your overall network design and the intended usage of the network switch. If it’s replacing or supplementing an existing installation, we review the current network switch’s use and configuration, align those to best practices, and deploy the new switch to achieve a supportable installation with the least interruption to your business. When we’re replacing existing equipment, replacing a network switch will require us to schedule up to two hours of network downtime for your office with you. We will need that time to install the equipment, move the network cables across, and verify proper operation. If we’re replacing multiple switches at the same time, we may need additional time.
  • Remote Management Integration. The network switches we deploy for your organization should be able to participate in your overall network infrastructure management, permitting us to centrally define device types and policies to be applied to all equipment of that class.
  • Remote Diagnostics Capabilities. The network switches we deploy for your organization can provide details through our remote management tools of the number and types of devices connected to each port. Many models we recommend permit running electrical tests through the ports to determine connected cable lengths
  • VLAN configuration (Virtual Local Area Networks), for logical segmentation between different types of devices or traffic. Often used in conjunction with a Network Firewall to limit which devices can interact, or be restricted to internet-only services. The most common VLAN configurations are to separate voice (telephone desk set) traffic from regular business data traffic, or to separate privileged-access wireless network users from guest-access, internet-only wireless network users.
  • PoE configuration (Power Over Ethernet) PoE is the capacity of the network switch to provide low-voltage power over the in-wall network cables it’s connected to, based on the anticipated number and type of devices that expect to be powered. Common PoE devices include telephone desk sets, network wireless access points, IoT environment sensors, and security cameras or access control devices.
  • Physical environment. As active pieces of electrical equipment, switches need clean power, preferably from a battery-protected power source and adequate ventilation. Network switches that are actively providing low-voltage power to a large number of connected devices tend to draw many watts of power, which results in heat that needs to be managed and dissipated with appropriate HVAC capacity. Ideally, there would be some noise isolation, so the switch’s internal cooling fans don’t disturb people working nearby.
  • Mounting options. 95% of the time, network switches are designed to be mounted in standard 19”-wide equipment racks or brackets. Most network switches take “1 unit” (1U) of space; about 1.75” vertical inches. For smaller installations or branch closets, we can sometimes mount switches flush to a wall via a fire-resistant backer board installed by your building maintenance or cabling vendor, but that’s much less common.

Best Practices for Networks with Multiple Network Switches 

It’s common in most business networks to have multiple network switches, either because the number of wired network devices exceeds the capacity of most single network switches, or because your wired network devices are spread throughout a larger office area or campus with multiple wiring closets.

When a network has or requires multiple network switches, we configure all the network switches to consistently interoperate according to our best practices:

  • For networks that have one or more VLANs defined, the VLAN definitions should be consistent across all switches, even if no ports (other than uplinks) participate in particular VLANs on a given network switch.
  • For all network switches located in the same equipment rack or closet, if the switch models support stacking via a manufacturer interface or recommendation, we’ll configure stacking such that all the network switches in that physical group can be managed as a single logical unit.
  • If all network switches support Spanning Tree Protocol (STP), we enable and configure it on all the switches, and configure switches to have redundant physical paths to their adjacent neighbors. In most cases, this permits the majority of the network to continue to operate even should one network switch fail.
  • If all switches cannot support either stacking or STP, we’ll configure the switches in a tree arrangement, with the “topmost” switch of the tree being the fastest device with most of the high-bandwidth loads on it (such as servers, Internet uplink, core operations, cross-site connections, engineering workstations, etc., as capacity permits). Supplemental switches will then be connected to the ports of that switch, cascading down the tree until all switches have an uplink connection to either the core switch or a switch one step closer to the core. Best practice design should not have any switch more than five switches deep from the core.
  • Some switches support channel or port bonding, such that multiple physical ports can be configured to operate as a single logical port with increased performance. Bonding should only be considered if the volume of traffic expected on the branch switch to the core will regularly exceed a single port’s capacity and the core switch and the branch switch do not have available higher-performance interfaces or cannot be replaced with units that do.
  • Connections between network switches in physically separate areas should generally be made using fiber optic cable. Copper cabling has a 100-meter distance limitation and can introduce electrical noise and inconsistencies if the building has multiple electrical grounds.

Network Switch FAQs

How many years will a network switch last?

Network switches are active pieces of electronic equipment. They have manufacturer support, hardware warranties, software updates, and they are subject to wear-and-tear. To keep your switch supportable and manageable, we require your network switches to have current, maintained manufacturer support. This is often purchased as a term warranty or an annual support renewal during the switch’s useful life. When performance, security, features, and capacity aren’t in question, we recommend considering replacement of most network switches after six to eight years of operation, or once the model is no longer supported by the manufacturer, whichever comes first. Failing network switches can cause difficult-to-isolate communication problems on your network, affecting one person or device, or affecting an entire area of your building, or even affecting everyone and everything on your network.

Do I need to keep my network switches under a manufacturer support agreement?

In most cases, yes. We recommend operating modern, managed infrastructure devices, which means that most network switches are designed to participate as “smart” devices with all your other like-model network infrastructure equipment. That requires an active software license for each device, including each network switch or we can no longer manage the device. Many types of subscription-licensed network switches will no longer function without an active software and support subscription.

When you’re replacing a switch, can you reuse existing network patch cables?

In most cases, yes.  If your current network patch cables are clean, of the appropriate lengths, have intact connectors, and are rated for the proper electrical category to support the speed of your new network switch, they can be reused. Standard copper network cables, often less than $5 each, are not significantly expensive compared to the price and lifecycle of the switch and it’s intended stable performance.

Positioning new technology for success takes more than technical expertise. Our IT support team can help set up your network switch.