Hubs vs Switches = Collision?

Discussion in 'OT Technology' started by psujeeperman02, Feb 13, 2006.

  1. psujeeperman02

    psujeeperman02 "Hi Sal"

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    In a company of about 75 users, i have them all hooked up to about 6 Linksys 10/100 hubs. Each hub is connected to a Linksys switch.
    Today, and i dont know if this has been going on for awhile, i noticed that the red LED collision indicator on two of my hubs was flashing pretty frequently.

    What could be all of a sudden causing these collisions?
    Is this an imediate issue that needs to be addressed for my network to function properly?
    what can i do to resolve this collision issue?
     
  2. Boogieman117

    Boogieman117 PSN: Boogieman117

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    Perform a port sweep if possible. Could be that one employee decided to use a P2P program or some spyware got infected on a machine and it's spreading.
     
  3. EagerZeroedThick

    EagerZeroedThick New Member

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    replace hubs with switches
     
  4. psujeeperman02

    psujeeperman02 "Hi Sal"

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    is it as easy as that? take out all of my 16 port 10/100 hubs and replace them with similar switches?
    will i need to configure anything else or is it more or less "plug n play"?
     
  5. EagerZeroedThick

    EagerZeroedThick New Member

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    first thing i would do is take down each hub 1 at a time until you find what computer connected to what hub is causing all the collisions.

    hubs really just suck.
    if you use switches such as cisco you could look at every interface to determine where and what kind of collisions/errors are occuring

    also if you have a Network Monitor you could see what IP is causing the collisions.
     
  6. k2737

    k2737 Active Member

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    Get managed switches if ya got the money. But yeah its plug and play.
     
  7. psujeeperman02

    psujeeperman02 "Hi Sal"

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    Bobby3111,

    What do you recommend as far as Network Monitors go?
    I downloaded a couple progs from download.com, but they seem to suck pretty bad. Any other recomendations?
     
  8. peerk

    peerk New Member

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    Do the spyware/virus/mp3 downloading checks like others said.

    But other than that, I wouldn't worry about collisions unless you notice slow speeds. Collisions are going to happen with hubs and they increase with an increase in network traffic.

    If you have a few power users on a hub that generate a lot of network traffic, you may want to replace it with a switch. But if it is just a group of secretaries that only check their email, I don't see a point in replacing the hub.


    Having hubs is also a privacy/security issue since any on the hub can monitor all the traffic on the hub.
     
  9. Peyomp

    Peyomp New Member

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    I doubt your hubs are actually hubs. They are probably switches.

    What is the exact model number you are using?
     
  10. psujeeperman02

    psujeeperman02 "Hi Sal"

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    They are Linksys 16 port 10/100 auto-sensing hubs. Model : EFAH16
    Linksys 16 port 10/100 auto-sensing hub
    Linksys 16 port 10/100 auto-sensing hub
     
  11. Peyomp

    Peyomp New Member

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    Not really a hub. Try sniffing it. Its a switch. They just call it a hub for the purposes of product differentiation. Its a marketting ploy.
     
  12. col_panic

    col_panic calm like a bomb Moderator

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    some places are so cheap it's appalling. when i first started working here the whole building was on hubs and the cat5 was split into two pair for each workstation. at the place where i worked before that we were on token ring with cat3 :run:
     
  13. Peyomp

    Peyomp New Member

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    They aren't that cheap. Those aren't hubs. They are switches.
     
  14. deusexaethera

    deusexaethera OT Supporter

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    To most people, hubs and switches are the same thing.

    Hubs are just connection splitters, like the things you use to hook two TVs to a single cable. Switches are marginally more complicated.

    You should consider replacing your existing hubs with switches and replacing your existing switches with single-subnet routers. Each router would issue IP addresses for a different subnet. (the third number would be different for each subnet.)

    Having all your networked computers sharing resources is a good thing, but there really isn't any need for them to be electrically connected at all times.
     
  15. Peyomp

    Peyomp New Member

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    This is the last time I am gonna say it... 99% of products called 'hubs' in the modern world are not 'hubs' but are 'switches.' I found this out when I tried to buy a 'hub' and kept being unable to sniff, when using it.

    His 'hubs' are not 'hubs,' they are switches.

    I've posted a link to a list of hubs that are real hubs before (someone search my posts in here), and I am 99% sure the one he listed is not one of those. They are really hard to come by.

    He can go to a managed switch for his main switch, if he needs to. But he doesn't HAVE to unless there are actual performance problems.
     
  16. deusexaethera

    deusexaethera OT Supporter

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    Is your implication that hubs are actually more useful under certain conditions, and therefore switches are sometimes intentionally mislabeled to attract buyers who specifically want whatever hubs can do? Interesting.

    So what is a hub good for that a switch is not good for? I was under the impression that hubs were the < * form of network sharing device.
     
  17. MAD PUNK inDC

    MAD PUNK inDC Sic Semper Tyrannis

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    thats not really an excuse though. I found Cisco routers and switches for under $50 all over the place. Hell I bought a 1900 switch for just $20. Sure they might be used, but they are reliable, and it's far better than monkey fucking a network together.
     
  18. col_panic

    col_panic calm like a bomb Moderator

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    no, they are hubs. i didn't say linksys. and i have a netgear hub that i bought specifically for sniffing connections - works fine.
     
  19. johan

    johan Active Member

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    assuming your description is correct, that your hubs are hubs and switches are switches...then

    get yourself a pc and download ethereal, its a cheap (free) sniffer.
    Attach to one of the hubs displaying excessive collision indicators.

    From the packet capture you can see which offending station(s) are responsible.
    There could be many reasons for this, it could be as simple as a nic card running amuck. It could be a particular pc infected with a dos type virus, etc.

    My point is in order to "resolve" the collision issue, you need to understand what is causing it.

    Simply rearranging the topology or changing out hardware (other than an offending nic) will not solve the collision issue.

    This also assuming your network is still usable, and the collisions are higher, but not excessively high to the point where the network segment (i.e. THAT HUB) becomes unstable or unusable. If that is the case (unusuable) then you might want to check for a physical loop condition.
     
  20. Peyomp

    Peyomp New Member

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    Thats great. You may have a real hub. I had to buy three to get a real one, which is how I found this out. I ended up having service make a 'snort device,' and it works great.

    But the thread is about HIM, and HE has switches.

    http://wiki.ethereal.com/HubReference

     
  21. XR250rdr

    XR250rdr OT Supporter

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    I've got a real hub :wiggle:
     
  22. Bob from Marketing

    Bob from Marketing OT Supporter

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    sniffing
     
  23. AO

    AO New Member

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    Macs.
     
  24. psujeeperman02

    psujeeperman02 "Hi Sal"

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    well, did some sniffing around, some logging, and some cold-hard detective work. turns out that one of our new PowerMac users have been downloading a bunch of audio and video podcasts via iTunes. You wouldn't think this would cause too many collisions, but we do most of our file sharing/transferring in the mornings, and it was just at a bad time for him to dl that stuff. Also, i have our Antivirus software search for updates 15 - 20 minutes after system start up. im going to fiddle with the settings to minimize collisions going forward. thanks for all of the info guys.
     

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