have to split 10/100 network into 2 hubs.. will this affect much?

Valhalla1

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Oct 13, 1999
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have 4 workstations and a server, wanted to get them all on the same hub (or upgrade to a switch) but because of certain problems, two workstations are stranded from the other side of the office but for 1 network link, so now I need to put half on one hub and the other half, and server, on another hub. all these workstations are point of sale pc's that run a software package all day that works on a 120+mb database files, and print on several network printers constantly (lots of network traffic basically), will splitting up this network affect the performance much, or am I just paranoid..
 

ttn1

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Oct 24, 2000
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I think mainly you are just paranoid. Wait, have to check the door again for the men in black suits.

Seriously though, if the hubs are 10/100 hubs then they will be sharing 100 Mbits/s to all the connections that are on them. So you have 4 connections on one hub, server, 2 workstations and the connections to the other hub. That means that if all connection were using max bandwidth, each connection would get 25 Mbits/s. The 2 machines on the other hub would recieve 12.5 Mbits/s each. This is assuming worst case scenario, all machines are pulling max bandwidth, which is highly unlikely. These numbers should be fine for accessing the database and printing.

Switches really help out with more workstations, because they allow each connection to have the full 100Mbps.

The truth is that if your database queries are handled efficiently, then I don't think that you will have any problem with you current setup. You'll probably notice more of a speed increase by getting a faster server, than you will by upgrading to switches.
 

ktwebb

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Nov 20, 1999
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Database apps are bandwidth pigs. Its not a given you'll see poor performance but its certainly possible. I would at least replace the main hub with a switch. That would cut down on the broadcasting and dedicate bandwidth to the remote machine.
 

ScottMac

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Mar 19, 2001
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You seem to have a pretty good handle on what PCs are sending to which other PCs, printers, and the server.

If the network is somewhere between light traffic and fairly busy, a second hub would work fine with no impact to the good or bad. It wasn't that long ago (actually I still know of some places) where *HUNDREDS* of users are on a single flat network segment......and working fine....it really depends on the amount of traffic and where it going.

The trend is for more traffic, especially in DB apps. Replacing the hub(s) with a/some switches is likely to improve your network throughput. A switch will allow people who are accessing the data, the people that are printing, and the people playing network games all get a discreet channel, with an apparent increase in bandwidth. Each pair of connections gets their own "pipe"....unless a bunch of people are going for the same thing, then that ONE channel to the resource is shared....no difference from a hub. A switch will also allow you to use "Full Duplex," which may also give you some increase in throughput (probably not, but it's possible...depends on whether the NIC drivers can support Full Duplex).

A switch will have no effect whatsoever on the broadcast traffic. At the layer that a switch works on (Layer Two), broadcasts are still propagated, but the collision domain is reduced or virtually eliminated (depending on the layout).

Another possibility, if you have two hubs and don't want to spend the money on a/some switch(es), would be to put a second NIC in the server (NICs are fairly cheap, even the good ones), each feeding one of the hubs and a couple users and printers. The trick here would be to make sure that the printers used by folks on segment one are also located on segment one (and the same for segment two). This accomplishes the same thing as a switch (reduction of collision domain) and also reduces the broadcast domain (since you have two totally separate segments).

Give it some thought and let "us" know......

FWIW

Scott
 

Valhalla1

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Oct 13, 1999
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right now I have the server and 2 workstations on a 10/100 switch I borrowed from my home network until a second 10/100 hub arrives.


the problem is there is limited space and wiring restrains which basically means 2 workstations are stranded on their own hub now with only 1 uplink to the second (switch). so you're suggesting I add a second nic to the server as the link to the second hub, instead of just uplinking the hub and switch. will this be possible and still have them all on the same subnet and ip range?
 

ktwebb

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Nov 20, 1999
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I stand corrected. Interesting too. I errouneously though broadcasting was cut out with switches for years. Difference is once the connection between two nodes is established i suppose. Sad given my experience. Too much RF LAN and WAN work and not enough wired devices. Oh well, learn something new and all.
 

ScottMac

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Mar 19, 2001
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If you add another NIC to the server, there would be two IP subnets. Depending on the app, it may or may not complicate things. If you put two workstations on a switch, aiming predominantly at the uplink, then they will share the uplink bandwidth (no real gain over the hub). Since you're terminating the uplink at a hub, any advantage you've gained is pretty much lost.

If you decide on getting new switches, perhaps you should look at the Gig package from LinkSys. They give you an 8 port 10/100 switch, and a gig NIC for the server (you ain't gonna get a gig out of it, but it's a wider path....).

Re-reading the initial post, to answer the question: No. There shouldn't be any problems or degradation by splitting the systems between two hubs. You would probably see some improvement using a switch, depending on the printer setups.. If the server is sending all the print jobs, then there wouldn't be much improvement, if any. If the PCs send the print jobs, then you're likely to see a noticable improvement. There are a lot of variables, but general, switches will improve a situation where there are multiple anywhere-to-anywhere "converations."

KTWebb: Switches are essentially a multi-port bridge. Some switch manufacturers DO add some sort of broadcast suppression (user configurable), but, as a basic function, as a layer two device, it's gonna forward broadcast/multicast traffic. Routers will stop broadcasts and multicasts (unless configured otherwise with an "IP Helper" enabled for broadcasts and multicast processes enabled for the multicasts). Even with IP helper turned on, you have to specify a destination for the broadcast, because it gets forwarded as a Unicast to that specific host.

FWIW

Scott
 

Valhalla1

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Oct 13, 1999
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hey, sounds like I do need to convince the man with the checkbook to get switches instead of a router, becuse the print jobs are all spooled from the various workstations.. in addition the printers are connected to different workstations, the server is not handling print jobs at this time due to its placement (the printers need to be out front on the sales floor). so all day the nodes are talking to each other printing stuff and also talking to the file server doing i/o on the database.

I need to put some sotware up there to monitor actual bandwidth usage.. i wonder how many collisions there are with the hub they have now on a busy day




<< If you add another NIC to the server, there would be two IP subnets. Depending on the app, it may or may not complicate things >>



all the app requires is a mapped network drive to where the database file is stored.. so all the underlying ip behind the windows network is transparent to the app I am working with
 

Garion

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Apr 23, 2001
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Switches don't really cost much more than hubs nowadays, and give FAR superior performance. This will actually be noticeable on your network, as it sounds like you do a lot of peer-to-peer printing. Since switches allow full duplex (bidirectional) traffic, a user won't be impacted when someone sends a print job to the printer on their PC.

The Gig setup that Scott references costs about $220. Dirt cheap and you can really impress your boss. Otherwise, you can spend about $80 on a decent 8 port 10/100 switch that will do the trick. Most non-techies don't understand how much prices have come down, so you can probably still stay way under budget and get switches instead of hubs.

One other note - I'd definitely NOT recommend splitting your users among two NIC's in your server. Since they print to each other's printers, the traffic would have to be routed through the server, adding a tremendous load on it. You'd actually be slowing your network down rather than speeding it up.

A 120 MB database is good sized, but not huge - Even a 10BaseT network should be able to handle it reasonably well. You're likely more bottlenecked on your server than on your network. You might check your RAM - You might get a cheap boost in performance by being able to add more memory and give it more disk cache.

- G

- G
 

Valhalla1

Diamond Member
Oct 13, 1999
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thanks for all the suggestions!

anyone know of some reg hacks or other settings somewhere in win2k pro that I could enable on the file server to increase its performance in sharing this database and doing i/o.. It will be getting a faster hard drive soon, and that should help a lot.

so increased ram on a peer to peer machine serving a medium to large size file to multiple clients will increase its disk cache? it doesnt seem to use much of the ram it has now.


hey that made me think.. would be REALLY cool if I had lots of ram and could just make a ram drive to store the database. :Q that should spead the SOB up quite a bit, no? but if the server were to crash and that database not copied to disk would mean losing all data entered since the last backup (every few hours the database is backed up to another client and onto cd at end of day)
 

ScottMac

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Mar 19, 2001
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I don't think MS has much of a disk cache. There are a number of caching controllers (IDE and SCSI) you can get and load up with RAM....that might be a better choice....and it can be moved to the next server if it doesn't have a killer drive subsystem.

FWIW
Scott