analogy for router,switch .. - Network

This is a discussion on analogy for router,switch .. - Network ; what are the good analogy from real life for router, hub, bridge switch. I have had hard time to understand them and why we need them!! what are the differences between them etc. I thought examples from real life would ...

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  1. analogy for router,switch ..

    what are the good analogy from real life for router, hub, bridge
    switch. I have had hard time to understand them and why we need them!!
    what are the differences between them etc. I thought examples from
    real life would help me to understand them. Thanks a lot for the help.

  2. Re: analogy for router,switch ..

    esara123@hotmail.com (esara) wrote in message news:...
    > what are the good analogy from real life for router, hub, bridge
    > switch. I have had hard time to understand them and why we need them!!
    > what are the differences between them etc. I thought examples from
    > real life would help me to understand them. Thanks a lot for the help.


    I'll give the examples starting from least complex to most complex.

    Hubs just increase access to a line. It is like power strips or
    electrical outlet splitters. Where before you had just one electrical
    plug on your wall it is now split into many different plugs. This is
    basically the same thing for hubs. Think of the ethernet line as an
    electrical line (which it really is, if you think about it.) The hub
    just gives you a way to split that line so that you can hook many
    things up to it. The only problem with that is that if more than one
    computer on the line starts to talk at the same time, the electrical
    signal gets all garbled up. This is called a collision. It's like
    people sitting around a dinner table talking. If just one person
    talks at a time and everyone waits their turn it is really easy to
    understand. But when everyone starts to talk at the same time it is
    impossible to make out what everyone is saying.

    This is where bridges come in. A bridge lets you hook more stuff up
    to the line, solving the need to get more access but helps to cut down
    on unnecessary talk. It separates your network into two different
    sides. You would put one segment of your network, like an accounting
    segment, on one side of the bridge, and another segment like human
    resources on the other. Normally, the two sides don't need to talk
    and the conversation is separated into two different sides. It would
    be like the people at the dinner table splitting off into two separate
    groups to discuss their own topics of interest. But sometimes one
    side needs to talk to the other side so it broadcasts a message to
    both sides asking for the desired information. It would be like the
    host of a party making an announcement, or one of the guests asking a
    question to everyone in the room. In technical talk, what is
    happening is this--you've separated your network into two different
    collision domains. This makes it so that there are less dropped
    packets. But the bridge doesn't contain broadcasts. They are still
    sent out to both sides of the network.

    A switch is an even better thing. Hubs and bridges really aren't used
    too much because they really aren't that effective. But you are
    seeing them make a comeback in wireless technology. For a switch,
    imagine something different. You know when you are driving and you
    come to a four-way stop that just has stop signs? It takes a while
    because everyone has to stop and decide who is going to go first and
    who will go next and there can be some confusion. Now imagine what it
    would be like if instead of the four way stop in your intersection you
    had an overpass. That way, one road could go over the other one and
    no one would have to stop. That is kind of a simple way to think of a
    switch. A switch does the same thing as a hub and a bridge, but it
    does it better. It lets you add more computers to your network, but
    it also makes little virtual connections between computers that need
    to talk. The connections aren't actually wired, but the computer
    inside the switch makes it so that that's what it appears to be. As
    soon as the computers are done talking to each other, the virtual
    connection is broken and it goes back to nothing. This pretty much
    eliminates the collisions. The only problem that a switch has is that
    it won't keep a broadcast from filling up the line. When one computer
    needs to know something, like the address of another computer it sends
    out a broadcast over to the whole network to find out what it is.
    This means that every computer in the network receives the broadcast
    and has to examine what it is saying to see if it is the intended
    recipient. This can tie up your network while it is being sent out
    because none of the other computers can send out a message while this
    is going on.

    Routers solve this problem. They do all of the stuff that a switch
    does, except they use a different method to address the packets of
    information. They use IP addresses. A router acts sort of like the
    post office. It decides the best route that a packet can take to get
    to different networks. A router can divide your network into
    different subnetworks and actually contain the broadcasts to a smaller
    area so that not all of your network needs to hear the broadcast when
    it is sent out. This keeps your resource from being tied up with
    unnecessary traffic jams. It would be like taking a city (that is
    your network) and dividing it up into smaller neighborhoods. They are
    smaller areas, but still part of the same city. When the residents in
    one area want to hold a neighborhood watch meeting, they can tell the
    post office to mail fliers to that one neighborhood or area so that
    the post office doesn't need to waste time or paper to send notices to
    neighborhoods that are far away. That is what a router can do if you
    program it to do that. It can contain the traffic to specific
    sub-networks so that they don't go to all the computers in your entire
    network. This saves your all-important resource which
    is-------------->BANDWIDTH.

    I hope that this helps you to understand those things a little better.
    This was something that I had a problem with at first and somebody
    told me these examples to help me visualize what the things do. These
    are pretty simplified examples, so it's not exact, but you can get the
    idea. If you have any more questions, or if these examples aren't
    clear, feel free to post more questions. Good luck!

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