what kind of network connections and intermittent failure we can come across this problem

Posted on 2005-03-31
Medium Priority
Last Modified: 2011-09-20

given a budget of 1000$ and asked to fix an unreliable ethernet network.There are 58 stations in the network and have a mix of 10/100mbps ethernet cards.wiring is also a mix of category 3 ,category4,category5 and it is not marked.It is not feasible to re-wire if possible ,because of cost. there are 5 hubs daisy chained together,Diagnose the client's issues with dropped network conections and intermittent failure if some stations to communicate on the network giv an appropriate plan for
improving the network using the eqp .Jusify ur answer with more than simple budget constraints.

10mbps hubs are $50 each ;10mbps switches are $100 each
100mbps hubs are $100 each;100mbps switches are $200 each
10/100mbps hubs are $200 each;10/100 mbps switches are $300 each
Question by:anumit
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Expert Comment

ID: 13674752
First off, I would get rid of the hubs.  Hubs broadcast packets wich causes uneccessary network traffic.
Considering your disposition, I would purchace less switches with more ports (24 port switches).
If you get a switch that only allows 100mbps you will have problems with nics that only perform at 10mbps
I would purchase the 10/100 mbps switches, they may be more expensive but in the long run its probably your best way to go.

Expert Comment

ID: 13674764
Also, if you decide to go that route, make sure all your nics' are set to "autosense" unless some only have a setting for 10 or for 100
LVL 13

Expert Comment

ID: 13675017
Because of the mix of wiring, if you want to "fix" the situation and not have to return, I'd stay with 10Mbps.  What will happen is that the switch will have to be configured constantly if you go with a 10/100Mbps switch because of the disparate cables and NICs.  If you happen to have a NIC that wants to auto-negotiate but its cable is the CAT4 or CAT3, the 100Mbps duplex is going to drop packest, and you won't look too good.

They have not asked you to improve their speed; they've asked you to improve the quality of their connections.  Personally, I'd set the switch ports to 10 half--all of them.
The goal is consistency in connectivity.  After you've satisfied that objective, if they complain about speed, you can up the duplex first, but that should come with an explanation that the potential for random drops exists.

You can explain to them that if they choose to, they can but the 10/100 switches for future growth, assuming that the'yy invest in recabling in the future.  Otherwise, the 100Mbps portion of the switch is just a number . . . CAT3 and 100Mbps solid--nope.
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Accepted Solution

fixnix earned 1200 total points
ID: 13676947
If the deal is "fix this, and we'll pay you $1000" for a network of that size....I'd run away.

What will happen *when* you replace a few cards, switches, hubs, and mibbie some easilly accessible cabling, only to find out there are more substantial problems...or (some of) the problems are caused by poorly configured hardware in the network like multiple DHCP servers dishing out the same address pool, windows 9x computers that just will crash anyway but the client blames on the network, a network copier/printer or 2 w/ a bad proprietary $500 network board, a phone system configured with the wrong subnet sending erroneous broadcasts but nobody knows the password or has the software to get in to fix it, a bad cable run behind drywall, under carpet, or otherwise not in the budget to fix, etc?

The client will simply say "Sorry, I won't pay you since you didn't honor your end of the bargain.  Have a nice day."

I'd also consider changing where I shop if you're paing $300 for a 10/100 switch (unless it's a managed 24 or 48 port unit...but since you said they currently have 58 workstations I'd extrapolate that there are around 70 ethernet devices wired in, and w/ 5 hubs, that puts the average one at 16 ports...or even one 48 port, one 10 port, and 3 dime-a-dozen 4 or 5 port units.)

Now if the job description is "Here's $1000, get it as good as you can", then that's a completely different story.

10Mbit switches are dirt cheap on ebay's even for quality brand managed 24 port units.  Heck...I've carted many out of clients' for free just because they're pretty much useless for most of today's modern network apps (not to mention roaming profile AD environments where employees save anything and everything on their desktop or "my documents").  If you go the 10Mbit route, buy/aquire 2 or 3 times as many as you need then give them a year warranty on the parts...chances are you won't have to replace more than one but even if you do, you'd have some in stock...and still come out ahead money-wise.

Expert Comment

ID: 13676963
I meant buy 2 or 3 times what you need *if* you go the used route.

If you can swing new then obviously you'd only buy what you need ;)


Expert Comment

ID: 13678735
IMHO, work out which pcs have cat5 to their rj45 jack and make sure they have a 100mbps nic installed while the cat3, cat4 and unknown cables have 10mbps cards, then get enough switches of both 10mbps and 100mbps to accomodate the pcs. This way the network will be as fast as possible without recabling and there will be less upgrade cost in the future.

Comments made above about half duplex for the 10mbps would be a good start for reliability only trying duplex to get speed if the link can handle it.

There may also be issues with connections on the ends of some of the patch cables, new ones could be a good idea, as well as checking for corrosion or poor crimping on the rj45 wall jacks and at the hubs. A reasonable cable tester would be handy for testing "dodgy" links.

Author Comment

ID: 13689033
Thaxs for the response and help in explaining this topic clearly.
LVL 13

Expert Comment

ID: 13722095
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