Choosing the Appropriate LAN Device
For this course, the choice of which router to deploy is determined by the Ethernet interfaces that match the technology of the switches at the center of the LAN. It is important to note that routers offer many services and features to the LAN. These services and features are covered in the more advanced courses.
Each LAN will have a router as its gateway connecting the LAN to other networks. Inside the LAN will be one or more hubs or switches to connect the end devices to the LAN.
Routers are the primary devices used to interconnect networks. Each port on a router connects to a different network and routes packets between the networks. Routers have the ability to break up broadcast domains and collision domains.
Routers are also used to interconnect networks that use different technologies. They can have both LAN and WAN interfaces.
The router's LAN interfaces allow routers to connect to the LAN media. This is usually UTP cabling, but modules can be added for using fiber-optics. Depending on the series or model of router, there can be multiple interface types for connection of LAN and WAN cabling.
To create a LAN, we need to select the appropriate devices to connect the end device to the network. The two most common devices used are hubs and switches.
A hub receives a signal, regenerates it, and sends the signal over all ports. The use of hubs creates a logical bus. This means that the LAN uses multiaccess media. The ports use a shared bandwidth approach and often have reduced performance in the LAN due to collisions and recovery. Although multiple hubs can be interconnected, they remain a single collision domain.
Hubs are less expensive than switches. A hub is typically chosen as an intermediary device within a very small LAN, in a LAN that requires low throughput requirements, or when finances are limited.
A switch receives a frame and regenerates each bit of the frame on to the appropriate destination port. This device is used to segment a network into multiple collision domains. Unlike the hub, a switch reduces the collisions on a LAN. Each port on the switch creates a separate collision domain. This creates a point-to-point logical topology to the device on each port. Additionally, a switch provides dedicated bandwidth on each port, which can increase LAN performance. A LAN switch can also be used to interconnect network segments of different speeds.
In general, switches are chosen for connecting devices to a LAN. Although a switch is more expensive than a hub, its enhanced performance and reliability make it cost effective.
There is a range of switches available with a variety of features that enable the interconnection of multiple computers in a typical enterprise LAN setting.