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intermediate systems | internet protocol stack | data transmission | network vs transport layer | encapsulation |
Intermediate Systems

Repeater, Hubs, Bridges, Switches and Router there exist many devices to interconnect different network segments or networks. To start with, these devices operate on different layers.

Repeater or Hubs work in the physical layer. They do not examine addresses, but instead send frames arriving on any interface to all other interfaces. Typically a repeater amplifies the incoming signal.

Bridges or Switches appear at the data link layer. They store incoming frames, extract the destination data link layer address (e.g. the 48 bit MAC address) from each frame and look it up in a table to see where to send the frame. A bridge can have interfaces for different network types (e.g. Ethernet and wireless LAN) and different speeds.

Routers work in the network layer. When a packet comes into a router, the data link header and trailer are stripped of and the network layer packet is used for detecting the output interface. For an IP packet, the routing software uses the destination IP address in order to find a route to the receiver. Then the IP packet is encapsulated in a data link frame and sent to the next system.

The application allows you to see the difference between repeater, bridge and router interconnecting two hosts