What are Switches?
Switches occupy the same place in the network as hubs. Unlike hubs, switches examine each packet and process it accordingly rather than simply repeating the signal to all ports. Switches map the Ethernet addresses of the nodes residing on each network segment and then allow only the necessary traffic to pass through the switch...
What are Switches?
Switches occupy the same place in the network as hubs. Unlike hubs, switches examine each packet and process it accordingly rather than simply repeating the signal to all ports. Switches map the Ethernet addresses of the nodes residing on each network segment and then allow only the necessary traffic to pass through the switch. When a packet is received by the switch, the switch examines the destination and source hardware addresses and compares them to a table of network segments and addresses. If the segments are the same, the packet is dropped or “filtered”; if the segments are different, then the packet is “forwarded” to the proper segment. Additionally, switches prevent bad or misaligned packets from spreading by not forwarding them.
Filtering packets and regenerating forwarded packets enables switching technology to split a network into separate collision domains. The regeneration of packets allows for greater distances and more nodes to be used in the total network design, and dramatically lowers the overall collision rates. In switched networks, each segment is an independent collision domain. This also allows for parallelism, meaning up to one-half of the computers connected to a switch can send data at the same time. In shared networks all nodes reside in a single shared collision domain.
Easy to install, most switches are self learning. They 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. A network composed of a number of switches linked together via these fast uplinks is called a “collapsed backbone” network.
Dedicating ports on switches to individual nodes is another way to speed access for critical computers. Servers and power users can take advantage of a full segment for one node, so some networks connect high traffic nodes to a dedicated switch port.
Full duplex is another method to increase bandwidth to dedicated workstations or servers. To use full duplex, both network interface cards used in the server or workstation and the switch must support full duplex operation. Full duplex doubles the potential bandwidth on that link.
We stock all versions of the Cisco 2960, 3650 and 3850 range of Catalyst switches. We also usually stock the Industrial Ethernet switches, 4500X and some other models. Plus all the options, Smartnet and licenses.
We are currently stocking the newly branded Aruba range of HP switches plus the modular based 5400R series. We can also supply the majority of recent HP switches and any modules both current and hard to find.