Repeaters, Hubs, Bridges, Switches, Routers & Gateways

Created by:David Elwell

Dorian GlassbergAlley Hennigan

• Classified as “unintelligent” devices.

• Two of the simplest networking devices.

Repeaters and Hubs

• Inexpensive.• Best used in a bus topology.• Being phased out in modern

networks.

Repeaters

• A repeater with more than one output port.

• Have an uplink port, that allows the hub to connect to another hub or another connectivity device.

Hubs

Hubs

Hubs do not separate collision domains

• Operate at OSI layer 2*• “Intelligent” devices

Bridges and Switches

• Divides a network into 2• No valid address, no data across the

bridge

Bridges

Bridges

Same as Bridges, but usually have multiple ports

Switches

Switches

• Isolate data flow • Improve performance

Multilayer Switch

• Layer 3 (Network) Switching• Router = Microprocessor• Multilayer Switch = Circuit Hardware

Bridges and Switches

Key devices for communication between networks

Routers and Gateways

Gateways

• “Protocol converters”• A network node used to interface

between different networks• Acts as an entrance to another

network• Routers are a special type of gateway

Routers

• Forwards data packets across computer networks

• Works almost exclusively at the third layer• History:

– Idea: 1972 by INWG– First model: 1981 through DARPA initiative

• Tiers:– Access– Distribution– Security– Core

Routers

A

B

C

ROUTERCA B