Layers Functionality Of Network Switches

This article presents a review about the different layers functionality of network switches in Open System Interconnection Model, which is the standard networking model.

Before discussing the functionality of network switches in different layers, let us know first about different layers of the networking model. Well, there are total of seven layers.

The Application, Presentation and Session layers together form the Upper Layer which is implemented in software.

The Transport and Network layers deal with protocols for delivery and routing of packets to a destination and these layers are implemented in software as well.

The Data Link layer of the networking model is implemented in hardware and software and the Physical layer is implemented in hardware only, also the reason why it is named as Physical layer. These two layers also define Local Area Network and Wide

At any of the layers in the networking model, the layer specific functionality of network switches may implement power over Ethernet, PoE. It eliminates the need of having a separate power supply for attached devices, like an IP telephone or wireless access point. Since in modern network switches, there can be redundant power circuits having connection with the uninterruptible power supplies, the attached device would continue to run the required functions even when regular office power fails.

Taking into account the second layers functionality of network switches, a network bridge which works at the sub layer of the data link layer known as Media Access Control (MAC), might be used to interconnect a small number of devices in a home or in an office. The layer specific functionality of network switches in the third layer within the boundaries of the Ethernet physical layer, a layer 3 switch can be used to perform some or all of the functions which are otherwise done by a router.

Fourth layer functionality of network switches is actually as defined as a vendor-dependent functionality as it usually starts with an ability to translate network address; however it then adds some kind of load distribution also in accordance with the TCP sessions. The devices might consist of an IPSec security gateway, stateful firewall, a VPN concentrator.

The seventh Layer specific functionality of network switches is that they might be used to allocate loads according to the URL or based on some installation-specific technique in order to identify the application-level transactions. The network switch functioning at the seventh layer might consist of a web cache and can be a part of the content delivery network.