Within the seven-layer Open Systems Interconnection (OSI) model, Layer 3 is the network layer. Layer 3 is involved in the forwarding of incoming data packets of variable length. This network layer includes the functioning and procedures that result in data transfers between network connection points. Because a network determines the method of delivering or routing messages, OSI model layer 3 is known as the network layer. It allows for traffic prioritization and data transfer based on type of message and destination. A number of protocols are associated with management of the network layer. Layer 3 functions also include filtering during packet inspections. In comparison to layer 3, the second layer in the OSI model involves media access control, flow management and error checking.

Network Layer of the OSI Model

The network layer receives requests from the transport layer (layer 4) and send requests to the data link layer (layer 2). A router is a commonly utilized layer 3 device. Operating at layer 3, a router will inspect the IP and IPX addresses of incoming data packets. After determining the packet source, the router will then make routing decisions based on the enclosed destination address and quality of service specifications. A layer 3 device can decide how to forward a packet across the network. Traditional switches operate at layer 2, however, layer 3 switch technology is an option for the large-scale LAN.

Fast Layer 3 Switches

High performance layer 3 switches offer network layer functionality. This type of switch can provide high speed capabilities as an alternative to the conventional router. It may be referred to as a routing switch or switch router. A routing switch performs packet inspections and supports routing. Contact Comms Express to obtain information about high speed switch routers.

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