A network switch is a small hardware device that joins multiple computers together within one local area network (LAN). They can increase the capacity and speed of the network. Switches are almost like hubs but unlike hubs, switches examine each packet and process it accordingly rather than simply repeating the signal to all ports.
These are very easy to install and determine the Ethernet addresses in use on each segment, building a table as packets are passed through the switch. This “plug and play” element makes switches an attractive alternative to hubs.
Switches can connect different network types (such as Ethernet and Fast Ethernet) or networks of the same type. Many switches today offer high-speed links, like Fast Ethernet, which can be used to link the switches together or to give added bandwidth to important servers that get a lot of traffic.
Each computer connected to a switch port can transfer data to any of the other port at a time.
- In half duplex mode, each line can only either receive from or transmit to its connected computer at a certain time. In full duplex mode, each line can simultaneously transmit and receive, regardless of the partner.
As more users are added to a shared network or as applications requiring more data are added, performance deteriorates.
- A moderately loaded 10 Mbps Ethernet network is able to sustain utilization of 35 percent and throughput in the neighborhood of 2.5 Mbps after accounting for packet overhead, inter-packet gaps and collisions.
- A moderately loaded Fast Ethernet or Gigabit Ethernet shares 25 Mbps or 250 Mbps of real data in the same circumstances. With shared Ethernet and Fast Ethernet, the likelihood of collisions increases as more nodes and/or more traffic is added to the shared collision domain.
Ethernet itself is a shared media, so there are rules for sending packets to avoid conflicts and protect data integrity. It is possible that two nodes at different locations could try to send data at the same time. When both PCs are transferring a packet to the network at the same time, a collision will result. Both packets are retransmitted, adding to the traffic problem.
Increased collisions are often the result of too many users or too much traffic on the network, which results in a great deal of contention for network bandwidth. For the reduction of collisions there are several dealers who have switches which have performance as per the requirement. They are:
a) Brocade Network Switches
b) Cisco Network Switches
c) Brocade SAN Switches
d) Juniper Switches
e) HP Switches
f) Netgear Switches
Different models of network switches support differing numbers of connected devices. Consumer-grade network switches provide either 4 or 8 connections for Ethernet devices, while corporate switches typically support between 32 and 128 connections.