Switched Networks

Switched Networks



Networks 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 change the way networks are designed. These changes will maximize productivity.
Switching technology is increasing the efficiency and speed of networks. This technology is making current systems more powerful. Many networks are experiencing bandwidth shortages. There are several reasons for this including: an increase in traffic, because networks have so many users, Amount of data between client/server applications, and the inefficient traffic patterns of most networks.
Switching directs network traffic in a very efficient manner. It sends information directly from the port of origin directly to its destination port. Switching increases network performance, enhances flexibility and eases moves, add-ons and changes. One of the benefits of switching is that it maintains a direct line of communication between two ports, and maintains multiple simultaneous links between various ports. It reduces network traffic by reducing media sharing.
This technology has some benefits over ethernet routed networks. First, a 10 Mbps or 100 Mbps shared media can be changed to 10 Mbps or 100 Mbps of dedicated bandwidth. Routers have many devices attached to their ports, sharing the bandwidth. Switches let you to connect either a shared segment of bandwidth (workgroup) or a dedicated one (server) to each port. Second, this can be done without changing any software or hardware already on the workstations Finally, a switch installation is less complex than a bridge/router configuration.
A ethernet LAN runs at 10 Mbps. Stations attach through a hub or repeater. Every station can receive transmissions from all of the stations, but only in a half-duplex. This means that stations cannot send and receive data simultaneously. In a ethernet network only one packet can transmit at one time, this is what slows down networks. The bridge, the router and the switch, all attempt to reduce transmission time to increase performance.
A two-port bridge splits a network into two physical segments and only lets a transmission cross if its destination is on the other side. It also will only move a packet to the other side if it is necessary. This reduces network traffic because traffic on one side stays local.
Routers link multiple networks together. It maintains the flow of traffic and routes data to the network that it must go to. (Each port has a unique network number.) it also has a "firewall" function. Bridges and routers have similar bus architectures. Switches eliminate the bus architecture.
Ethernet switches segment a LAN into many dedicated lines. A switch port may be configured in segments with many stations hooked to it or with a single station hooked to it. The rule is that only one conversation may originate from any port at a time, it doesn’t matter if there is one or a lot of stations connected to that port. All ports have to listen before they transmit. When a single LAN station is connected to a switched port it is in full-duplex mode. This helps because there are no collisions of packets since they are all separate ports. Full-duplex switching means traffic can be sent and received at the same time. Ethernet networks go from 100 Mbps to 200 Mbps. (hubs between a workgroup and a switch will not run full-duplex, the workgroup is unswitched ethernet.). Switches are starting to be more popular than routers and bridges. Switches now do the segmentation once done by routers and bridges. 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 it is inexpensive compared to one with customized CPU. RISCs are already somewhat common in businesses and are off-the-shelf processors. This type of switch can perform some functions similar to a router. The downside of this type of RISC is that it is a store-and-forward processor that is not as fast as an ASIC switch.
ASIC (Application Specific Integrated