Choosing the right campus LAN switch for your organization isn't simply a matter of understanding whether your network would benefit from access, distribution and core switches. There are plenty of other decisions that need to be made before you can narrow down your list to a specific vendor and switch model. Let's take a look at the features and capabilities you should consider when evaluating campus LAN switches.
Port speeds and interface connections
Your first consideration is to understand what port speeds your network requires and what port connection types would be most useful and/or cost-effective. Most modern campus LAN switches support a wide variety of port speeds, including 1 Gigabit Ethernet, 10 GbE, 40 GbE and 100 GbE. Most end devices will use standard Gigabit Ethernet connections, while servers and uplink ports may require much faster port speeds and multiple ports for redundancy.
You must also consider port speeds for the latest 802.11ac wireless access points (APs). These APs can now process more than 1 Gbps to connected clients. Because of this, a standard Gigabit Ethernet link may become a throughput bottleneck. To eliminate this problem, some network vendors are rolling out NBASE-T MGBASE-T and Institute of Electrical and Electronics Engineers' 802.3bz ports that provide 2.5 to 5 Gbps throughput speeds on CAT5e or CAT6 cabling.
In terms of interface connections, your most common options are copper, fiber and direct-attach copper. The decisions surrounding which interface connection type to use revolve around the required port speed and what type of cabling is already installed in a building or throughout a campus.
For example, if you have CAT6 cabling running from your access closet to every cubicle in a building, then these ports will use Gigabit Ethernet connections with standard RJ45 interfaces. And if each access closet is interconnected using multimode fiber, you will likely want to look at a switch that has small form-factor pluggable uplink interfaces so you can install LC fiber transceivers.
The number of connections you need will also greatly influence what switch type you should purchase. Fixed-port switches are usually cheaper, but you're stuck with the port numbers and types that come with them. Modular switches, on the other hand, can be upgraded, so you can easily increase the number of ports and change interface types.
Power over Ethernet
Many devices that connect to access switches can be powered using a Power over Ethernet interface. PoE uses the same copper cabling to provide both network connectivity and the necessary power, so it doesn't need to plug into a standard AC outlet. Common examples of PoE devices include IP phones, APs and internet-of-things sensors. There are several different PoE standards and each standard provides a different maximum per-port watt output. Therefore, it's important to know how much power your end devices actually require. Below are the power ratings for three popular PoE standards in use today:
- IEEE 802.3af-2003: PoE up to 15.4 W per port.
- IEEE 802.3at-2009: PoE+ up to 25.5 W per port.
- Cisco Universal Power over Ethernet up to 60 W per port.
Understanding how much throughput your network is likely to need -- today and several years into the future -- is a critical part of the purchasing process. Lower-cost access switches provide port density, but compared with switches designed for distribution and core switching duties, their maximum throughput specs are going to be considerably lower.
Switching performance also depends heavily on whether the switch will be operating at Layer 2, Layer 3 or both. And if the switch will be performing Layer 3 functions, it must be able to support the routing protocol that will be used. For example, almost all enterprise-grade multilayer switches can operate using static routes or open dynamic routing protocols, such as Open Shortest Path First. But if you need to run more advanced routing protocols, such as Border Gateway Protocol, or proprietary protocols, such as the Enhanced Interior Gateway Routing Protocol, you must ensure the switch you choose can run the necessary routing protocols.
Typical campus LAN designs call for a certain amount of built-in redundancy to maintain connectivity to the majority of users when a link or switch goes down. As you begin researching campus LAN switches, you'll likely find there are any number of ways to provide redundancy using both hardware and software. This includes redundant switches, uplinks and redundancy protocols running at Layer 2 or Layer 3. It's important to understand what redundancy techniques you want to use -- and verify that all of the necessary switches can perform the required redundancy tasks.
Physical environment considerations
Switches are deployed in a wide variety of physical locations. For example, switches that are deployed in manufacturing plants that are often hot or humid may fail if the incorrect switch hardware is used. In situations where switches will be deployed in harsh environments, specially designed switches built to better withstand heat and lack of air flow would be a better long-term option. You'll also find compact and reduced-depth switches for deployments where space is limited.
An enterprise switch literally has hundreds of features, so it's up to you to decide which ones you need and which campus LAN switches can actually provide that feature. Some examples of advanced switch features include:
- Converged wired or wireless;
- Enhanced security features;
- Built-in troubleshooting tools; and
- Automated integration with external troubleshooting and management tools.
Lastly, before choosing a campus LAN switch vendor, you need to thoroughly understand the support offerings and prices for the switch hardware and software you're about to buy. For example, some vendors offer free and unlimited access to switch firmware updates, while others require a support contract before you can download any updates or patches. Hardware replacement warranties also vary greatly. A few vendors offer lifetime hardware replacement warranties on some switch types, while others offer only 90-day or one-year warranties. Once support contracts are in place, those warranties can then be extended.
Online and phone technical assistance and troubleshooting support are also important considerations. A technical support contract provides an added layer of technical expertise to handle any misconfigurations or hardware and software faults, so you can better maintain a stable campus network.
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