1. NET 324 D
Networks and Communication Department
Lec1 : Network Devices

2. Hubs and Repeaters
Typical LAN devices include repeaters, hubs, bridges, switches, and routers.
A repeater receives the signal, regenerates it, and passes it on.
Repeaters are used mainly at the edges of networks to extend the wire so more workstations can be added.
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3. Hubs and Repeaters
Using a hub changes the network topology from a linear bus, where each device plugs directly into the wire, to a star.
Data arriving over the cables to a hub port is electrically repeated on all the other ports connected to the same Ethernet LAN, except for the port on which the data was received.
Hubs come in three basic types:
Passive
Active
Intelligent

4. Bridges and Switches
Bridges and switches operate at the data link layer of the OSI model.
The function of the bridge is to make intelligent decisions about whether or not to pass signals on to the next segment of a network.
When a bridge sees a frame on the network, it looks at the destination MAC address and compares it to the forwarding table to determine whether to filter, flood, or copy the frame onto another segment.

5. Bridges and Switches
Switches learn certain information about the data packets that they receive from computers on the network.
They use this to build forwarding tables to determine the destination of data being sent by one computer to another on the network.
They help segment a network and reduce network traffic congestion by limiting each port to its own collision domain.

6. Routers Routers operate at the Network layer of the OSI model.
They are slower than bridges and switches but make "smart" decisions on how to route packets received on one port to a network on another port.
Routers are capable of segmenting the network.
Routers are capable of segmenting a network into multiple collision domains as well as into multiple broadcast domains.

7. Routers
Routers can be computers with special network software installed on them or they can be other devices built by network equipment manufacturers.
Routers contain tables of network addresses along with optimal destination routes to other networks.