Edge-Core switches: Layer 2 vs Layer 3

Edge-Core switches: Layer 2 vs Layer 3

You’ll find them tucked away in the corners of offices and racked up in server rooms in most organisations, but there’s more to the humble switch than meets the eye

Network switches are often described as Layer 2 or Layer 3. But what exactly does that mean and what are the advantages and disadvantages of the technologies involved?


Layer 2 Switches (The Data-Link Layer)


Layer 2 switches operate using the data link (MAC) layer addresses. Link-layer, hardware, or MAC-layer addresses identify individual devices. Most hardware devices are permanently assigned this number during the manufacturing process. Switches operating at Layer 2 are very fast because they’re just sorting MAC addresses, but they do not look at the Layer 3 portion of the packet to learn anything more.

Because Layer 2 information is easily retrieved, packets can be forwarded (switched) very quickly, typically, at the wire speed of the network. Layer 2 switching, therefore, has little or no impact on network performance or bandwidth. And because no setup or management is required, the Layer 2 switch is cheap and easy to deploy.

What Layer 2 switches can’t do is apply any intelligence when forwarding packets. They can’t route packets based on IP address or prioritise packets sent by particular applications to, for example, guarantee bandwidth to Voice over IP users.

The information required for that only starts to become available at Layer 3 (the Network Layer).


Layer 3 Switches (The Network Layer)


Layer 3 switches use network or IP addresses that identify locations on the network. A location can be a LAN workstation, a location in a computer’s memory, or even a different packet of data traveling through a network. Switches operating at Layer 3 take more time examining packets than Layer 2 devices and incorporate routing functions to actively calculate the best way to send a packet to its destination.

Other intelligence commonly found in Layer 3 switches, includes the ability to logically segment a network into two or more Virtual LANs (VLANs) plus enhanced security controls to prevent unauthorised setup changes. Facilities to prioritise different types of traffic are also commonplace, to provide guaranteed Quality of Service (QoS) when, for example, building converged voice and data networks.


Which Switch?


Layer 2 switches are the ideal cost vs performance switch, although slightly more expensive than a layer 1 switch; a Layer 2 switch allows you to switch data faster to the designated end point or device.

You would primarily make use of layer 2 switches where connected clients do not need access to the internet as this would require the switch to understand IP addresses. A good example being a security surveillance installation, as the cameras do not require internet making itmore cost effective and slightly better in performance to use Layer 2 switches.


Edge-Core’s range of Layer 2 switches available from MiRO:

EC-ECS4110-52P   Read More

EC-ECS4210-28P   Read More

EC-ECS4510-52P   Read More


Edge-Core’s range of Layer 3 switches available from MiRO:

EC-ECS4620-28P  Read More

EC-ECS4620-52P  Read More

EC-ECS4620-28F  Read More

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