Switched NetworksNetworks are getting more and more popular,and because of this more people use them, which slows them down. Networks in the future will need to have enough bandwidth to support applications,like multimedia, witch require larger bandwidth. Switching will changethe way networks are designed.
These changes will maximize productivity. Switching technology is increasingthe efficiency and speed of networks. This technology is making currentsystems more powerful. Many networks are experiencing bandwidth shortages. There are several reasons for this including: an increase in traffic, becausenetworks have so many users, Amount of data between client/server applications,and the inefficient traffic patterns of most networks.
Switching directs network trafficin a very efficient manner. It sends information directly from theport of origin directly to its destination port. Switching increasesnetwork performance, enhances flexibility and eases moves, add-ons andchanges. One of the benefits of switching is that it maintains adirect line of communication between two ports, and maintains multiplesimultaneous links between various ports. It reduces network trafficby reducing media sharing.
This technology has some benefits overethernet routed networks. First, a 10 Mbps or 100 Mbps shared media canbe changed to 10 Mbps or 100 Mbps of dedicated bandwidth. Routers havemany devices attached to their ports, sharing the bandwidth. Switches letyou to connect either a shared segment of bandwidth (workgroup) or a dedicatedone (server) to each port.
Second, this can be done without changing anysoftware or hardware already on the workstations Finally, a switch installationis less complex than a bridge/router configuration. A ethernet LAN runs at 10 Mbps. Stationsattach through a hub or repeater. Every station can receive transmissionsfrom all of the stations, but only in a half-duplex. This means that stationscannot send and receive data simultaneously.
In a ethernet network onlyone packet can transmit at one time, this is what slows down networks. The bridge, the router and the switch, all attempt to reduce transmissiontime to increase performance. A two-port bridge splits a network intotwo physical segments and only lets a transmission cross if its destinationis on the other side. It also will only move a packet to the other sideif it is necessary. This reduces network traffic because trafficon one side stays local.
Routers link multiple networks together. It maintains the flow of traffic and routes data to the network that itmust go to. (Each port has a unique network number. ) it also has a “firewall”function. Bridges and routers have similar bus architectures.
Switcheseliminate the bus architecture. Ethernet switches segment a LAN into manydedicated lines. A switch port may be configured in segments with manystations hooked to it or with a single station hooked to it. The rule isthat only one conversation may originate from any port at a time, it doesn’tmatter if there is one or a lot of stations connected to that port.
Allports have to listen before they transmit. When a single LAN station isconnected to a switched port it is in full-duplex mode. This helpsbecause there are no collisions of packets since they are all separateports. Full-duplex switching means traffic can be sent and received atthe same time. Ethernet networks go from 100 Mbps to 200 Mbps. (hubs betweena workgroup and a switch will not run full-duplex, the workgroup is unswitchedethernet.
). Switches are starting to be more popular than routersand bridges. Switches now do the segmentation once done by routers andbridges. Switches can do more than put a packet to one side or the other- they send traffic right to its destination. RISC (Reduced Instruction Set Computer)is a type of CPU to process in switches. It is used for general,or simple task, RISC switches are not as well at performing specific tasks.
One of the advantages of RISC is that itis inexpensive compared to one with customized CPU. RISCs are already somewhatcommon in businesses and are off-the-shelf processors. This typeof switch can perform some functions similar to a router. The downsideof this type of RISC is that it is a store-and-forward processor that isnot as fast as an ASIC switch.
ASIC (Application Specific IntegratedCircuit) This is the other design widely used in switches to process. Theyare custom designed to handle specific operations, all of the functionsare in hardware. If any changes are needed, manufacturing must be doneto rework hardware. No software upgrades are available.
Another type of network architecture thatis benefiting from switching is, token ring. One of the advantagesis ? faster and larger networks. Since switches do all of the workthat routers and bridges do, and are deticated, it makes since that companiesare using more and more switches in a token ring network. There isanother technology that is starting to get more popular than ethernet ortoken ring, it is called ATM. Asynchronous Transfer Mode (ATM), is sometimescalled technology of the future, but it is being used today. A major plusof ATM is that it is the first technology that can deliver different typesof traffic, such as voice, video and data, over a single digital line.
ATM can also handle scaleable amounts of bandwidth, as a result of itsswitching architecture, which can support multimedia applications and networkgrowth for years. Within the last year or so, ATM is getting more and morepopular with businesses, and companies are now have test networks of alltypes. Many have begun the transition to ATM networks, while others arewaiting for technical committees to finalize ATM standards that will addfeatures and flexibility for their networks. Companies are trying to understandATM technology and how it will effect their business.
They are aware thatthe cost of ATM products has fallen dramatically in the last year. ATM’sslightly higher cost over shared networks (Ethernet, Token Ring. ),is justified by three times the performance. This access allows for moreproductivity in the workplace.
With a business wanting more and morespeed and reliability there will be and is new technology coming out everyday. It is important for telecommunications professionals, and businessesto understand what exactly the new technology will do to help improve profit.
