Film-Tech Forum ARCHIVE: Hub Help

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Posted by Michael Brown (Member # 890) on 04-06-2003, 04:04 PM:

Just a basic question about hubs since I need to replace the one that is in our office.

Are they all pretty much generic?

The one at the moment is for 5 computers. But its owner wants to retrieve it.

As long as a buy another one that also has 5 ports in it, will it be ok? Or are there any specifications I need to look out for?

Posted by Ian Price (Member # 14) on 04-06-2003, 04:08 PM:

When the professional installers ran network cable here at the theatre, they removed all of our hubs and replaced it with a switch. Looks the same, does the same thing, but they told me it would work better.

It hasn't let us down yet.

Posted by Michael Brown (Member # 890) on 04-06-2003, 04:42 PM:

I guess I just need something like this

Posted by Adrian Steiner (Member # 1527) on 04-06-2003, 05:11 PM:

A hub connects all computers with the same speed, a switch with different speeds. IIRC hubs connect mostly with 10Mb/s (anyone correct me, if I am wrong here.).
When you have a network in which all but one computers have a 100Mb/s card and one has a 10Mb/s card, the maximum bandwith with a hub will be 10Mb/s, even if you copy data between 2 computers with 100Mb/s cards.
When using a switch, you have 100Mb/s between 2 computers with 100Mb/s, and 10Mb/s between computers with a 10 Mb/s and 100Mb/s cards.

c't (a german computermagazine) tested some time ago various hubs & switches. They didn't find big differences in performance (not hubs vs switches, but expensive vs cheap switches/hubs). As switches are not much more expensive than hubs, I'd buy a switch.

Posted by Michael Brown (Member # 890) on 04-06-2003, 06:26 PM:

I got slightly confused. It isn't for 5 computers. It is for 4. The fifth port is where the hub plugs into the network socket on the wall.

EDIT: Also, I need to figure out what the sockets are. They are not USB. So I guess 10BASE-T or ETHERNET.

Posted by Mark Lensenmayer (Member # 134) on 04-06-2003, 07:41 PM:

Connectors are RJ-45, similar to a telephone connector (RJ-11) but with 8 pins. For all practical purposes, 10-baseT and Ethernet are the same.

You may need a crossover cable from the device to the wall. I'd just reconnect that cable that was there.

Way to tell a crossover from a straight-through...look at the ends. If the color sequence doesn't match, its a crossover. If they are the same, a straight-through.

There is a standard color sequence for cables. 568-B cables are Orange/White- Orange-Green/White-Blue-Blue/White-Green-Brown/White-Brown.

568-A standard is Green/White-Green-Orange/White-Blue-Blue/White-Orange-Brown/White-Brown.

Straight through has same standard on each end, crossover has 568-A on one end and 568-B on the other.

The 4-pairs are wrapped at different rates to eliminate crosstalk. In these types of cables, the color makes a big difference.

Michael, I agree that a switch is best. There are some cheap switches out there that outperform hubs. I just bought one for about $30 that works just fine for me. You certainly don't need to spend many hundred dollars for a switch any more.

Posted by Joe Redifer (Member # 3) on 04-06-2003, 08:32 PM:

Hubs are just stupid. Everyone who is cool uses a switch. Ian is cool. Hubs share bandwidth. So if you are transferring one file to another computer and two other computers are doing the same thing at the same time, the bandwidth is split in half. With a switch, all four computers would get the 10/100 speed. Just because two computers on your network are transferring files doesn't mean your computer will get bogged down.

Buying a hub makes you less of a man. I have 15 hubs. [Smile]

Posted by David Stambaugh (Member # 1102) on 04-06-2003, 08:46 PM:

What Joe said is correct for data transfers across ports on the same switch. But if multiple clients on the switch are simultaneously accessing upstream resources (via the switch's uplink port), the bandwidth will still be split up. Although that issue can be mitigated if you have a switch with a gig uplink port. [Wink]

Does anyone even make hubs any more?

Posted by Scott Norwood (Member # 30) on 04-06-2003, 08:47 PM:

For simple networks (like what Michael has), the difference between a hub and a switch will be minimal and isn't worth worrying about.

Hubs and switches can be either 10 megabit, 100 megabit, or dual-speed. Get a dual-speed model to avoid any potential issues. Some will have an "uplink" port, which does the same thing as a crossover (flip) cable, so you can just use a straight-through cable to connect the hub/switch to the wall.

There's not much difference in "cheap" hubs/switches--they either work or they don't. The "expensive" ones (usually in the $600 range for about 24 ports) offer useful management and troubleshooting features, but are unlikely to be more useful than the cheap models for Michael's purpose.

Posted by Barry Floyd (Member # 385) on 04-07-2003, 09:07 AM:

We've got 4 of those really small 3Com "Office Connect" 8-port hubs here at the office. There's no configuration to it, just plug'em in and they work.

I never really understood the difference between a hub and a switch... they look the same to me.

Our network here is pretty simple. 14 work-stations and 4 network shared printer/copiers. We are getting ready to upgrade to a server with hot-swappable drive arrays, and it scares the crap out of me. I don't have a clue about a server, and I'm the one who'll have to fix it if it breaks.

Posted by John Hawkinson (Member # 1135) on 04-07-2003, 09:45 AM:

It's worth noting that there is a lot of industry confusion about terms like "hub," "switch," "bridge," "repeater," and even "router." The terms have evolved and changed over time, and not to the benefit of clarity or consistency.

The definitions given earlier in this thread are the generally accepted ones (hubs do not isolate the collision domain and share the bandwidth across ports, switches can let each port reach the full bandwidth when talking to any other port), but that is not universal, so check closely the specifications on what you purchase if it matters.

Also, switches have finite backplane bandwidth, so a cheap 10-port 10mbps switch is unlikely to support 5 10mbps conversations between pairs of ports.

--jhawk

Posted by Mike Rendall (Member # 1499) on 04-07-2003, 10:17 AM:

I take it you need the hub to connect to a standard uni network?

In our case, we just buy a standard Netgear 5port switch 100M/10M. You can buy them from Misco quite cheaply (they also give university discount - Make sure when you order it that they have the correct account for you). We use Netgear all the time, they work well with minimal fuss. Part No:FS105/ Misco No:40297, Price £31.99 (usually less 10-15%) +VAT

You don't need a cross-over cable (cos it is all automatic nowadays) just plug them all in and the unit will figure out which one is the internet and which ones are your PC's. A 100Mb switch will last near enough for ever.

Posted by Michael Brown (Member # 890) on 04-07-2003, 01:28 PM:

quote:
I take it you need the hub to connect to a standard uni network?

Yeah. 4 computers and the wall socket.

Posted by Stephen Furley (Member # 1277) on 04-08-2003, 07:10 AM:

I would recommend the Netgear FS105 5 port switch, there's also the 8 port FS108 if you need it. They are low cost, small, well built with metal cases, and seem to be reliable. We have loads of them. They do 10 or 100 Mb/s, have auto uplink (no need for crossover cables), the only problem we've had was with a few of the very early ones where the power supply plug was a poor fit, but that was some time ago. All the more recent ones have been fine.

Hubs are still made, but there's not much point in them now, the cost per port is only slightly less than with a simple, unmanaged switch, and there's no problem connecting a mixture of 10 and 100 Mb/s devices. Dual speed hubs were made, but they were more of a bridge, with slow devices one side, and fast ones on the other. I'm not sure if anyone is still making them, but they would probably cost at least as a switch now.

You do not say where your data is going, is it all to/from remote servers, or is some of it between the local machines? If the latter, the switch is definately the better option.