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Help with topologies?

Discussion in 'Networks & Internet Connectivity' started by Princey, 11 May 2006.

  1. Princey


    Joined: 26 Apr 2003

    Posts: 5,608

    Location: Staffordshire

    Say I have a star topology that has six computers connected around a central hub. If computer 2 wanted to communicate with computer 5, could computer 2 send the message to the HUB and then the HUB send the message to computer 5? Would any other computers get to see the message?
    Also in a ring topology with 6 computers would would computer 2 communicate with computer 5? Is the message passed to each computer and then forwarded on until it reaches number 5?
  2. PeterNem


    Joined: 15 Feb 2003

    Posts: 8,322

    Location: NJ/NY, USA

    The hub is "dumb" - it doesnt do any sending.

    Within a colision domain I beleive all computers will see the transmission, but unless they match their IP address to the one in the destination IP address in the header, they will ignore it.
  3. mcdiejdh


    Joined: 9 Mar 2003

    Posts: 69

    Location: Manchester

    Hi there,

    With the hub it just retimes the signal and forwards it out all interfaces. This puts all the PC's within the same collision domain.

    So the upshot of the star with a hub is that all PC's will see all of the traffic.

    With the token ring network the token is passed around the ring so once again all will see the traffic.

    This is why switches are used in preference to hubs since they create seperate collision domains for each interface.

    Hope that helps
  4. crashuk


    Joined: 7 Dec 2005

    Posts: 2,691

    would just be a bus topology, get a switch.
  5. Stellios


    Joined: 27 Aug 2004

    Posts: 17,023

    Location: Geordieland

    The HUB does nothing, all it does is pass data back out, which means collisions in data transfar can occur IIRC. The data is transmitted to all computers, but only the computer with the correct IP Address and port will actually interpret the data. If you fancy checking this out then i believe Linux has a packet sniffer, go onto a PC and recieve data that your PC wouldnt normally recieve with it.

    Again, all computers will receive the data, but only the one with the correct IP and prt will interpret the data. Again, fancy checkingit out then try a packet sniffer and it should show the data going across the network to all PCs.
  6. just_grass


    Joined: 15 Dec 2003

    Posts: 975

    Location: Bedford/Derby, UK

    Not quite true, say 5 pcs in a token ring, - PC1 sends data to PC3, only pc1, pc2, and pc3 will know of the data.... as it gets picked up and sent on the segments between PCs1 and 3. the data *should* never touch PCs 4 or 5.

  7. [email protected]

    Wise Guy

    Joined: 29 Oct 2005

    Posts: 2,450

    Location: Newcastle upon Toon

    Packet sniffer wise, i can recommend Ethereal - really easy to use with a nice interface.

    Also, it's actually really hard to get hold of a hub nowadays, even things labelled as hubs are now actually switches - this is a good thing since they are much more efficient anyways! :)