Networking hub. Does no one sell them anymore?

Discussion in 'Networking' started by alfa147x, Nov 30, 2012.

  1. alfa147x

    alfa147x Lifer

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    I remember seeing a lot of discussion a few years ago about switches vs hubs. The reasoning for switches is that they only send devices the data meant for them.

    I'm trying to put something between a HP MSM313 and a cisco switch to allow me to hook up one temporary device. The network admin said to go ahead as long as it doesn't cause any issues with their setup.
    I'm thinking if I get a hub vs a switch it'll be less interruptive. Thoughts?

    The network admin told me we should be able to test a small unmanaged gigabit switch on Monday. Just trying to brainstorm alternative ideas.

    Thanks!
     
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  3. VirtualLarry

    VirtualLarry Lifer

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    Do you need to monitor/log/sample the data going over a port, or to just add a spare port somewhere to plug in an additional device? If you just need to add a port, then any old unmanaged switch would work.
     
  4. alfa147x

    alfa147x Lifer

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    No monitoring / log / sampling (Not that I need to do that. But a managed switch would do that. Right? )

    That's what I thought. I had a unmanaged gigabit switch in and a few weeks later they started having "backlogging" problems (Not from the network admin. I think the guy is an intern or assistant). So the admin had me remove the switch and wait till monday to see if the issue continues.

    Does backlogging due to a switch make any sense? It seems from my short conversations with these guys that they are CATV and Telcom guys.
     
    #3 alfa147x, Nov 30, 2012
    Last edited: Nov 30, 2012
  5. theevilsharpie

    theevilsharpie Platinum Member

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    No mainstream networking vendor sells hubs anymore, and there's very few reasons why you'd want one. You may be able to get them from a specialty manufacturer somewhere, but I can't think of any offhand.

    I have no idea what "backlogging" is.
     
  6. IndyColtsFan

    IndyColtsFan Lifer

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    Yes, a managed switch with port mirroring would allow you to monitor traffic on specific ports if that's what you need.

    Here is a definition of backlogging:

    So what he is saying is that he thinks your switch was bogging down under high traffic load and was slowing the network segment down.
     
    #5 IndyColtsFan, Dec 1, 2012
    Last edited: Dec 1, 2012
  7. Tsavo

    Tsavo Platinum Member

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    Assists in forensic backtracing.

    ^_^
     
  8. unokitty

    unokitty Diamond Member

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    Have you considered a network tap?

    Uno
     
  9. Nothinman

    Nothinman Elite Member

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    You'll be interrupting the MSM regardless of the device you choose since you'll have to unplug it for a second. Besides that, the only other issue I can think of right now would be a loop caused by you plugging the new switch back into the network via 2 ports. And that could be bad regardless of whether it's a hub or switch.
     
  10. theevilsharpie

    theevilsharpie Platinum Member

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    Modern full-duplex Ethernet doesn't use CSMA/CD at all. If a switch interface is at capacity and its buffers are full, it will start dropping frames, or it will send out PAUSE frames if flow control is enabled.
     
  11. alfa147x

    alfa147x Lifer

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    The switch I used initially has 128 KB Buffer Memory

    These two have more. Would I be work while upgrading to the hp?
    144 KB (Rosewill RC-409LX)
    512 KB (HP V1810-8G)

    I'm confused. Why is the new switch being connected to the network with two ports vs just one?
     
  12. theevilsharpie

    theevilsharpie Platinum Member

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    You're overthinking this. If you're out of Ethernet ports and need to connect an additional device, just plug in a small switch and plug your devices into it. A 5-port Gigabit Ethernet switch is cheap and you can get them from pretty much any vendor that sells consumer electronics devices.
     
  13. alfa147x

    alfa147x Lifer

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    Right. I have plenty of those. But this is the issue I was trying to solve:

     
  14. Red Squirrel

    Red Squirrel Lifer

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    Another issue is trying to find a hub that is gigabit, did they ever even make those? You can probably ask them to mirror a port, that should allow you to plug a laptop with wireshark or do whatever it is that requires a hub. If you just want extra ports then a cheap switch is fine.
     
  15. alfa147x

    alfa147x Lifer

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    Apparently the gigabit spec doesn't allow hubs due to latency.
     
  16. Danimal1209

    Danimal1209 Senior member

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    If a switch is causing too much lag, for some reason, then a hub would not help. It would create more traffic since it is such a dumb device.

    A hub sends out all frames it receives out every interface. a switch contains a MAC table so it will only send out the proper port, reducing traffic.
     
  17. Red Squirrel

    Red Squirrel Lifer

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    Makes sense, imagine the collisions when actually pushing gigabit speeds. :eek:

    It would be jamming more than a rock concert.
     
  18. alfa147x

    alfa147x Lifer

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    Just had a voicemail left. It's a no go. He said something about adding a switch causing back feed. Anyone know anything about that?
    The only thing I can find is feeding power back back into the grid.

    Thanks for the help.

    Edit: I'm pretty sure at this point they don't want us hooking stuff up but don't have a good excuse. If someone can verify that "back feed" is bullshit I'll just escalate it to my boss and have him take care of it (if needed have a new drop run)
     
    #17 alfa147x, Dec 3, 2012
    Last edited: Dec 3, 2012
  19. alfa147x

    alfa147x Lifer

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    Lol
     
  20. Spicedaddy

    Spicedaddy Platinum Member

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    Are they using PoE (power over ethernet) for the MSM313 access point?
     
  21. alfa147x

    alfa147x Lifer

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    Yes. But they have a Dc adapter near by for backup. Also we have a HP JD483B#ABA PoE Injector.

    The Dc adapter is Oem.

    Would either one cause back feed ?

    I feel stupid for to even thinking one of them could cause an issue. Any idea how to verify?
     
    #20 alfa147x, Dec 3, 2012
    Last edited: Dec 3, 2012
  22. theevilsharpie

    theevilsharpie Platinum Member

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    I have no idea what either "backlogging" or "backfeed" are. Either the network admin is blowing smoke up your ass, or he is actually having a problem but isn't expressing it in industry-standard terminology.

    Ask for specifics.
     
  23. ScottMac

    ScottMac Moderator<br>Networking<br>Elite member

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    Hubs have virtually no latency; they are repeaters. Latency is added by the store & forward technology commonly used in switches these days. Cut-through switches added only a little latency, but don't really permit the advanced features that a store & forward switch offers.

    There are no Gig hubs because technology was well past hubs when gig was introduced.
     
  24. mammador

    mammador Platinum Member

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    Hubs are a 1980s technology.

    I think now that most networked nodes need a dedicated communications path, hubs went out long ago.

    If one has a network of a server, a printer, several desktops, and a couple of cameras, collisions are a no-no. I'm also surprised that CCNA still teaches students about hubs, it's not something most networking professional will apply in an enterprise or even home setting.
     
  25. Red Squirrel

    Red Squirrel Lifer

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    Heck CCNA still teaches about thinnet and thicknet lol. It's like A+ and having to know IRQs or details on 486 processors (number of pins etc), I don't get why these tests cover such old concepts that are not really needed to be known off hand in the real world.
     
  26. Nothinman

    Nothinman Elite Member

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    Did you take your CCNA recently? Because I don't remember seeing anything in the 640-802 exam specifically about thicknet in the book I have here. Hubs and such are covered because it's the best way to show why switching was introduced and the advantages it provides.