Switching and Routing

This paper was written to help the reader with a better understand of the concepts of switching and routing that is used in a network environment and the various hardware and software associated with their functions. First to be discussed are the concepts of switching including: store and forward switching, cut through switching, fragment free switching, and V-Lan. Furthermore the concepts of routing will be discussed to included comparisons of routed vs. routing, classful vs. classless, and distance vector vs. link state protocols.

Switching

A switch is a small device that joins multiple computers together to form a local area network (LAN). A switch works on layer two of the Open Systems Interconnection Reference Model (OSI Model). A network switch inspects the data packets for the destination information and then forwards the data on to the specific location rather that dispersing the data evenly across a network. This is the reason why a switch is also called a smart hub. The network bandwidth is better controlled since the data is forwarded to the intended location (Mitchell, 1999).

Store-and-Forward Switching

The switching method that, after inspection, stores the data packets for delivery is called the Store-and-Forward switching. Once the data is received from the send, it passes a redundancy check and a check to ensure it fits the size limitations. Once the data has been inspected and checked for errors the data is stored in a physical storage until the network is available for the data to be sent to its destination (Cisco Systems, 2008).

Cut-through Switching

The switching method that uses only the destination information to switch the data packets to the specific destination is called Cut-through switching. Although previous store-and-forward switches that examine the whole packet took longer to process the data than did the cut-through switching method with today's technology the difference in speed has become minimal (Lantronix).

Fragment-Free Switching

There are hybrid switches available today that combine both store-and-forward and cut-through switching methods. These hybrids are known as runtless or fragment-free switches. Fragment-free switches were designed to solve the late-collision problem and are primarily used in the backbone of congested networks. These hybrids check both the source and destination MAC address of a packet then make the appropriate switching to send the packet to its corresponding destination (Javvin Technologies,Inc., 2008).

VLANs

VLANs or Virtual Local Area Networks are logical local area networks that extend beyond the traditional LAN architecture. Because a VLAN is a logical entity, creating and configuring a VLAN is done completely in software. The advantages to using this