Ethernet Question

I just started reading the 70-293 MS Press book where it says, "...standard Ethernet
LAN can have up to four hubs, while a typical Fast Ethernet LAN can have only two. Gigabit Ethernet supports only a single hub on a network." Now I know this book may be a bit outdated and these days switches are used over hubs, would this rule apply to switches as well or only to hubs? And is their a limit on number of switches on a network for Ethernet? So far the beginning chapter seems pretty boring I feel like I'm back in my Networking 101 class in high school talking about the OSI layer etc.

thanks,

win2k8

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Devilsbane

I have never heard of any limit on the number of hubs. I don't think you would be stopped from adding too many, I think its more of a suggestion. If you stick too many hubs on your network you are going to be creating a lot of collision domains.

Sticking with switches is a better options. Your data transmission will still be slowed down if it has to pass through 25 switches, but I don't think it is something that a human would really notice.

Fugazi1000

An Ethernet hub is actually a multiport repeater - i.e. it regenerates the signal. Because of this, there is a limit to how many segments you can have. This is also speed dependant. 10Mb is 5 segments (4 hubs) and 100Mb is 3 segments (2 hubs). It's all to do with the timing and the ability to detect collisions. As for Gigabit - this is point to point - so no CSMA/CD.

HTH.

dynamik

Fugazi1000 wrote: »

An Ethernet hub is actually a multiport repeater - i.e. it regenerates the signal. Because of this, there is a limit to how many segments you can have. This is also speed dependant. 10Mb is 5 segments (4 hubs) and 100Mb is 3 segments (2 hubs). It's all to do with the timing and the ability to detect collisions. As for Gigabit - this is point to point - so no CSMA/CD.

Exactly. Performance just degrades. You could probably do more, especially if you're just testing something like two PCs pinging each other across a dozen hubs. In practice, something like that wouldn't be usable for any real network.

Devilsbane wrote: »

If you stick too many hubs on your network you are going to be creating a lot of collision domains.

No, you'll still have a single collision domain. That's the problem.

Devilsbane

dynamik wrote: »

No, you'll still have a single collision domain. That's the problem.

What I meant to say was that you will create a lot more collisions, and your network will spend all of its time resending data than doing any work.

motogpman

Wow, how old is that exam book?

skyline

MCSE Self-Paced Training Kit (Exam 70-293): Planning and Maintaining a Microsoft® Windows Server™ 2003 Network Infrastructure

Author Craig Zacker
Pages 992
Disk 1 Companion CD(s); 1 Evaluation CD(s)
Level All Levels
Published 08/27/2003
ISBN 9780735618930

veritas_libertas

Only proving once more that it is time to retire the MCSE

*Hides and waits for the tomatoes to be thrown

Devilsbane

veritas_libertas wrote: »

Only proving once more that it is time to retire the MCSE

*Hides and waits for the tomatoes to be thrown *

They could just update the test with current standards. But why would they bother, MCSE is already on its way out.

dynamik

I'm not throwing tomatoes, but the majority of the networks I see are still predominately (if not exclusively) 2003. I still see hubs in production too.

veritas_libertas

dynamik wrote: »

I'm not throwing tomatoes, but the majority of the networks I see are still predominately (if not exclusively) 2003. I still see hubs in production too.

Oh, I agree with you on that. We are still using majority 2K3 servers at work. I'm talking about getting rid of a certification path that is plenty old by now. I'm sure I will be using 2K3 in some capacity for many years to come.

Fugazi1000

They are actually keeping the MCSE exam up to date!! I sat the 293 yesterday and got a question referencing Windows 7 as the client computers in a scenario. Actually the fact it was Win 7 made not a blind bit of difference to the answer and I suspect until last year XP was used. But it does mean they are 'upto date'!

As for Hubs and segment limitations - this will never change - it's IEEE 802.3 - regardless of the current (or not) versions of a Microsoft NOS.

Devilsbane

Fugazi1000 wrote: »

Actually the fact it was Win 7 made not a blind bit of difference to the answer and I suspect until last year XP was used. But it does mean they are 'upto date'!

90% of the information that they give you in a question rarely gets used. They just want to give you everything so that it doesn't give away what road they are trying to lead you down.

motogpman

There are many MS subjects on the 293 that aren't used by a lot of companies or even that their IT staff are aware of that's available. It's foundation and good to know however. I also had some newer OS/tech info thrown into the test when I last took it, so at least they are trying to stay somewhat current. I think that the OP's study material might need to be updated, 2003 is quite a bit ago.