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Modem vs Router

  • A modem is what brings the internet into your home or business. A computer only reads digital signals. The internet only reads analog signals There different types of modems.

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    The modem modulates and demodulates (modem means modulator & demodulator) :
    - demodulates incoming analog signals into digital signal.

    - modulates outgoing digital signals into an analog signal.
    Two of the most common types are cable & DSL modems Depending upon what type of internet you're going to use, you need to use the correct type of modem.

    Cable modems are connected to your home using a coaxial cable

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    DSL modems are connected using a typical phone line.

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    There are two types of routers : business router & small office/home-office router.

    A router (which comes after a modem) is what routes internet connection to all of your devices.

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    Typically the modem will be a modem/router combination.

    • Hub, Switch, & Router

  • A hub, switch, and router are similar but handle data differently.

    A hub is connects all network devices on an internal network. It's a device that has multiple ports that accepts Ethernet connections from network devices. A hub is considered
    not to be intelligent
    . because it does not filter any data as to where the data is supposed to be send. When a data packet arrives at one of the ports, it is copied to all other powers. So all the devices on that hub sees that data packets.

    When this happens it not only creates secuirty concerns, but it also creates unnecessary traffic on the network, which wastes bandwidth.

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    A switch is similar to a hub. It's a device that has multiple ports that accepts Ethernet connections from network devices. Unlike a hub, a switch
    is intelligent
    . A switch can learn the physical addresses of the devices that are connected to it and it stores these physical addresses, called MAC addresses, in its table.

    So when a data packet is sent to a switch, it's only directed to the intended destination port. The switch will look at its table of MAC addresses and matching ports and deliver the data to the correct port. Switches are far more preferred over hubs because they reduce any unnecessary traffic on the network.

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    Hubs and switches are used to exchange data within a local area network. They are not used to exchange data outside their own network (such as out in the internet).

    Hubs and switches do not read IP addresses. A router is a device that routes (fowards) data from one network to another based on their IP address. When data packet is received from the router, the router inspects the data's IP address and determines if the packet was mean for its own network or it's meant for another network. If the router determines that the data packet is meant for its own network, it receives it. If it's not meant for its own network, it sends it off to another network. A router is essentially the gateway of a network.

    • What is a Server (review)

  • A server is a computer program or device that provides services on behalf of clients (such as ordinary desktop computers or workstations).

    Servers are centralized machines where multiple clients connect to, either over the Internet or in a local area network, and they connect to a server for a specific service. A server stores, sends, and receives data.

    That service could be to retrieve a website, access data, email, etc. A server could be dedicated to handle one of these services only.

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