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ethernet LAN mixed-speed setup

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November 13, 2006 4:08:37 PM

This is my first time on Forumz, so please be patient. I run a 25-user peer-to-peer LAN that grew by accretion from a 6-user LAN, with an odd mixture of hubs / switches / NICs throughout. It's ethernet, mostly 10/100 and CAT5e cables. Our "server" is a LAN-HD for 'common' (shared work & reference) files, which also gets me past the 10-user limit imposed by Windows XP-Pro. Recently some of my users have complained about retrieve/resave slowness on the LAN-HD, so I had a thought - but before I spend a bunch of money, please advise me if I'm grossly wrong, and thanks in advance.

IF the Main Switch and LAN-HD were 10/100/1000 (gigabit) connected w/ CAT6 cables, would all the 10/100 users 'share the bandwidth' and get improved speed? Or would the Switch and/or LAN-HD get 'dumbed down' to 10/100, resulting in NO speed increase?

I recognize that CAT5e cables have a limit of 350Mb/s, so if all LAN devices including sub-switches & NICs must be 10/100/1000, my users could at least have a 3.5x speed improvement. But I'd like to know in advance if it's going to be $600 or $2,000 (or more!) to achieve this.
November 13, 2006 5:55:53 PM

Your layout may be too complicated or Rube Goldbergesque to give simple answers.

Basically, all clients attached to a hub share the bandwidth, whereas with a switch, client a talking with client b takes no bandwitch away from client c talking with client d.

If you have mixed-speed clients (some 10 and some 100), the first thing I might do is pitch the hubs and replace them with switches. This would at least get your 100Mbps clients using their full speed when talking with other 100Mbps clients.

If you are thinking of upgrading eventually to 1000Mbps, then be sure to get 1000Mbps capable switches.

The cable would seem to be the least of your issues at the moment.
November 13, 2006 7:10:38 PM

Yes, Rube Goldberg would have enjoyed my LAN. Thanks.

My current main Switch (not a hub) is 10/100, as is my LAN-HD. When I see 1000 switches in the store, they have only one or two 1000 sockets, and the rest are 100. So, do you think that if I provide a 1000-wide path through a 1000-switch to a 1000-LAN-HD, will the 11 users directly connected to that Switch get 90Mb/s each? or will an unsuspected 100-bottleneck force them to share a 100 at only 9Mb/s each?

The other users will just have to struggle along unless I replace both the 10/100 sub-hubs (yes, they ARE hubs) w/ 1000-switches.

I'm just trying to save some money. If the sub-hubs don't NEED to be 1000Mb/s in order to serve some of my users better, I'd rather not spend extra $. And I'm glad to know that you think recabling and new NICs are less pressing issues right now.
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November 13, 2006 7:54:48 PM

My technology vendor just said I am unlikely to get any improvement unless I upgrade EVERYTHING to 1000Mbs.
November 13, 2006 8:00:12 PM

The Rube G remark was not meant to be a criticism - only meant to describe a network that just kind of grew to where it is instead of being laid out all at once... :wink:

But, putting together the pieces of information you have provided:

1) 25 clients plus a HD server
2) A 10/100 switch with 11 users attached
3) 2 hubs to connect everyone else.

How many ports are on your switch?

Are all of the NICs in your client machines / HD server 100 capable, or do you have some 10-only NICs?

As to the partial gigabit switches, I don't doubt they are out there, but there are plenty of full gigabit-capable switches, too... pretty reasonably priced as well. Check this link out: http://www.tigerdirect.com/applications/category/catego...|c:201|c:596|&Sort=4

(you'll have to copy and paste the link in your browser, since the resolve URL code on this board seemed to be confused by the "|" characters in the link.)
November 13, 2006 8:01:51 PM

Quote:
... vendor ....
Key word.
November 13, 2006 8:16:02 PM

General advice: before you start spending money, find out what the problem actually is.

For example, if you have 25 users all pounding on the same HD server constantly, and all 25 have the same priority or importance to you (that is, you as the network admin need to provide them all the same quality of service), then clearly the performance of the HD server is the bottleneck and you'll want to focus there.

If you have some 10Mbps clients attached through hubs, they are slowing down everyone attached to that hub.

But, on the bright side, if your more important / bandwidth needy users are attached directly to the switch, and the HD server is also attached to that switch, then the sub-hubs act as a throttle limiting network demands on the switch from everyone attached to the hubs. So, replacing the hubs may make matters worse for your higher bandwidth users.

Piece-by-piece upgrading does not waste any money so long as it is in the direction of the general upgrade. Sure, your vendor would rather have the purchase order for the entire network, siwtches, cable, etc., all at once, but unless you have the budget for that, tell him that if he cannot be more helpful, maybe you need a new vendor.
November 13, 2006 9:00:09 PM

Thank you so much for your time and advice! You are nearly correct in assuming that all 25 users require the same priority. It looks like I now have a one-piece-at-a-time program to follow:

1) Get a LAN-HD with a faster ethernet port, OR split the data onto two separate LAN-HDs; then wait for more 'slowness' complaints before:
2) Replace the 100Mbs switches & hubs with 1000Mbs devices, remembering to use CAT6 cables between them all; wait, etc:
3) Replace all 10/100 NICs with gigabit cards.
4) replace all CAT5e building cabling w/ CAT6.
At this point there's no more that can be done with 'normal' LAN equipment - my users will just have to deal with it. Hopefully Step 1 will by itself accomplish most of my goal.

Thanks again, you are a credit to the Internet. I salute you!
November 13, 2006 9:29:06 PM

If everything you have is Cat5e, replacing the cable would be the last thing on my list. Cat5e can handle gigabit. Cat6 is actually overkill for gigabit. You are unlikely to see any difference in performance except on very long cable runs (approaching the 100 meter limit).

However, if you are buying new cable, then by all means, get Cat6.

My order of proceeding would be:

1) Test the performance of the connection from selected clients to your HD server. You need actual data, not just quantity of complaints. Try to do this testing in normal use scenarios; for example, with the network and users up and running accessing the server, etc., grab one of the workstations and run some large file read / write tests and time the results. I'd recommend you do this at various workstations and various places in your network topology.

2) Develop an incremental plan for getting to where you want to be. A fundamental decision is do you want to end up with a managed or unmanaged network? Unmanaged in cheaper and easier to install, but managed offers advantages in monitoring the network performance and adjusting the bandwidth allocations, etc. You need to decide this before you buy a new switch. If your vendor is actually helpful (as opposed to being a salesman), he can advise you here.

3) Upgrade the NIC in your HD server to gigabit and replace your current switch with a gigabit switch. Don't waste your money on a switch that does not have all ports gigabit capable. Buy this switch based on your managed / unmanaged decision.

4) Re-run your tests and compare results.

5) Based on the results, decide what to do next.

PS: Your old switch can be used to replace your hubs at this time, too, if the hubs are in the same place.
November 13, 2006 10:13:25 PM

Quote:
1) Get a LAN-HD with a faster ethernet port, OR split the data onto two separate LAN-HDs; then wait for more 'slowness' complaints before:


You can replace it with a faster port, but there are other factors besides LAN port speed.

1. Interface speed is going to be either
A. IDE 100 or 133 (unlikely) MB/s
B. SATA 150 or 300 MB/S

2. Drive throughput is going to depend on the specific drives you choose.
A. Check out Tom's Hardware Guide for Hard Drives for actual drive
throughput: http://www23.tomshardware.com/storage.html

3. The number of drives you have in the Network Hard Drive

4. RAID config (if any) will affect throughput as well.

here's the other THG guide to NAS devices that relates specifically to NAS (network hard drive storage) that you can look at to get some comparisons on how well certain setups do and what interfaces they have on them: http://www.tomsnetworking.com/nas/charts/index.html?cha...
November 14, 2006 1:23:55 PM

Good thing I'm not a fast buyer.
Your linked chart shows my LAN-HD (Buffalo 250 USB) to be rather slow. Since Buffalo's my brand-of-choice, I'm glad to see the gigabit version did better in the test.
Since I'm ignorant of what brand of HD is inside the LinkStation, the performance data from the other link-chart isn't germain. But it's clear that SATA3 is best, and it was a little surprising that cache size / spin rate don't seem to affect LAN performance much.
So, if I can, I should get SATA3 w/ a gigabit ethernet port.

I'm still fuzzy about the managed/unmanaged network deal. Right now, each user has maximum draw on the LAN-HD - if I go with a managed setup, it sounds like I'm imposing deliberate data-bottlenecks on each user, which I'm generally opposed to, and the benefits aren't apparent to me. I admit to being a cheap bahstid, and a fan of path-of-least-resistance, so unmanaged looks more attractive to me. Hub-recycling is a way of life, too - both sub-hubs in my LAN were once the main hub in prior lives.

Thank you both for all your efforts to save me from myself; I feel like I'm nearly ready to go a-buying.
November 14, 2006 1:48:20 PM

Quote:
Good thing I'm not a fast buyer.
Your linked chart shows my LAN-HD (Buffalo 250 USB) to be rather slow. Since Buffalo's my brand-of-choice, I'm glad to see the gigabit version did better in the test.
Since I'm ignorant of what brand of HD is inside the LinkStation, the performance data from the other link-chart isn't germain. But it's clear that SATA3 is best, and it was a little surprising that cache size / spin rate don't seem to affect LAN performance much.
I'm not sure the Buffalo LinkStation is up to serving a 25 user network. If you are sure a small NAS appliance is what you want, at least make sure you get the LinkStation Pro. Its performance is significantly better than the standard LinkStation gigabit.

I put in a LinkStation Pro for a small office. With a 100Mbps LAN, they see read/write performance of ~65Mbps. If they put in 1000Mbps, this might go up to near 120Mbps, maybe a little higher, but it would not approach 1000Mbps. For that, you need a higher performance NAS. Of course, they also cost more.
December 12, 2006 1:33:02 PM

My new LinkStation Pro 10/100/1000-400GB is performing well - I no longer have users knocking down my door and threatening me with bodily harm. The old LinkStation 10/100-250GB is still being used for less speed-intensive file storage. Thanks again for all the good advice.
December 12, 2006 4:30:57 PM

Happy to help.

And, thanks for letting us know how things worked out. :wink:
!