Home Network Upgrade

soulselekta · 07-15-2003, 02:01 PM

Currently I have 5 computers hooked to a hub which is hooked to a single port router, connected to a cable modem. This works fine for sharing the internet connection, but when sharing files (especially large ones) between computers, it's extremely slow (running at 10mbps, I'm being limited by some device, not the NIC's). I believe the cable is regular Cat5, so if I should upgrade to Cat5e, I'll do that. i've also been told that it's it the hub which is slowing everything down. I was considering just getting a 5 port switch similar to this one: Linksys Switch on Newegg

So hopefully I could have all 5 pc's hooked into it and have the cable modem going into the uplink port. Would this be what I want to do? Thanks for the help!

Edit: Also thinking about running freesco on one of the extra boxes to serve as a firewall if the switch doesn't offer that feature.

**SKI** · 07-15-2003, 02:26 PM

Ideally, you want to retain your Router and buy a bigger switch. The 5-port linksys will actually only accomodate 4 PCs and the uplink to your 1 port router. It will also work if you run freesco on one box (5 PCs or 4 PCs + uplink to router), but then you'll need 2 nics in the freesco box, which you'd have to run full time as a router. Since you already own a router, I see no reason to dedicate resources on a PC to do the routers job.

Also, to ensure 100Mbps you need to confirm that all your NICs can run at that speed. As for specific hardware, try this switch or this one. 8 ports, $45 for either...

To recap, I'd just put an 8 port switch in place of your current hub. BTW, there's no reason to replace your cat5 with cat5e unless one or more of the current runs aren't in spec and don't support 100Mbps. In a commercial network I'd have the cable plant tested and certified before changing from 10Mbps to 100Mbps, but the cost is prohibitive for a home network. The easiest way to go is to hook up the new hardware, try to run @ 100, and replace any cable runs where you can't get to 100Mbps.

HTH

soulselekta · 07-15-2003, 04:14 PM

I'm ordering the Linksys switch today, thanks for the help!

soulselekta · 07-16-2003, 03:15 PM

Out of curiousity.. what's the difference between a hub and a switch? Besides the increase in speed, are there any other advantages?

**SKI** · 07-16-2003, 04:25 PM

Simply stated: a hub works like an old-fashioned telephone party-line. Everyone can hear everything, and only one person can talk at a time (or nobody can tell who's saying what). A switch is more like our modern telephones. Connections are established between specific devices, and everybody can call someone else and talk at once without coufusion. There's more to it than that, but that's the meat of the issue: you wind up with more effective bandwidth even given equal speed.

And now, for those of you with time on your hands, here's a little more detail...

Hubs create a shared connection. Anything that goes in a port is sent out all other ports (called flooding), so every other NIC has to decide if every packet is intended for it. This consumes some resources on every PC connected to the hub. Further, with a hub/shared media, two PCs can send traffic at the same time, creating a digital collision and requiring both PCs to resend that data. Only one PC at a time can transmit when you're using a hub. Technically this is called half/duplex communication, and the mechanism that Ethernet uses to handle this is referred to as CSMA/CD (carrier sense multiple access/collision detection). So yes, there are more disadvantages to a hub than just raw speed. BTW, there are 100Mbps hubs in existance, but the cost is unreasonable when compared to unmanaged switches like the one you're ordering.

Switches are more sophisticated. When traffic comes into a switch port, the switch takes note of the sending and destination NICs MAC addresses (by reading them off the data packet) and enters sending MAC address into a table relating known MAC addresses to switch ports. If the switch doesn't have the destination MAC address in its table, it floods the traffic out all ports. If the switch has an entry, it sends the traffic out just the port that relates to the known destination MAC address. This drastically reduces LAN traffic volumn.

Switches are also (in general) capable of supporting full-duplex communication. This allows PCs to both transmit and receive packets at the same time. The switches ability to learn MAC addresses allows it to go one step further than just reducing traffic: by relating just two ports to a particular data "conversation" it constructs a dedicated link between the two PCs involved. This uses a second pair of wires in the Ethernet cable and allows the PC on each end to send and receive traffic at the same time. Notice that with such a dedicated two-way link you've just virtually eliminated collisions. This is referred to as full-duplex Ethernet communication, and in fact the CSMA/CD mechanism is disabled, which reduces communications process overhead and speeds throughput. This feature is why some switch manufacturers advertise "speeds up to 200Mbps" for what is by definition a 100Mbps full-duplex switch: they mean 100Mbps in each direction at the same time. Any occasional collisions that occur are dealt with via software in what's referred to as the "upper layers" of the communications stack.

Finally, there is the matter of range. A hub has a fixed 100 meter range, PC to hub. So does a switch in half/duplex mode: this is a timing component of CSMA/CD, intended to prevent what are referred to as "late collisions". When you convert to full-duplex communications, you turn off CSMA/CD and thus the limitation on overall distance is now 100 meters FROM DEVICE TO DEVICE, and the practical limitation becomes how good your wiring is, interference, and how good the hardware is at regenerating signals (which is another function of both switches and powered, or "active" hubs). In this scenario you can put, say, 3 switches between two PCs, and with 100 meters between each device you've just spanned 400 meters. Usually this sort of thing goes on only in very large buildings. Between buildings (and over long runs in general) it's advisable to use fiber links due to electrical safety and other issues.

I could go on and on... there are a lot more things you can do with switches that just don't work with hubs...

See what curiosity gets you?

GreyFox · 07-16-2003, 04:35 PM

I thought I read somewhere that a hub divides the speed among the active pc's, where a switch allows all conections to run a full speed. Is this true?

zsaz1029 · 07-16-2003, 04:41 PM

You just summed up the first half of my Intro to LAN class from last semester.

Quote:

Originally posted by SKI
I could go on and on... there are a lot more things you can do with switches that just don't work with hubs...

See what curiosity gets you?

This is interesting stuff. What else can a switch do?

FWIW I'm using one of these at home.

**SKI** · 07-16-2003, 05:07 PM

With managed switches you can do things like:

Create Virtual LANS (VLANS) independent of physical proximity

Manage redundant LAN links for reliability (Spanning Tree Protocol)

Create multi-link traffic paths for increased link capacity (port channels, generally on trunk links) and multi-VLAN trafic paths (VLAN trunking)

Improve routing performance using multi-layer switching (also handy for ToS/QoS issues). Think switching at layer three and layer four rather than routing, although things get realy blurry here

Implement security policies (Port security based on static or dynamic MAC address learning, and by limiting the number of MAC adresses that the port will accept)

Can you say "CCNP"?

If you REALLY want to freak out, take a look at MPLS (Multi-Protocol Label Switching)!

I'm still working on this one...

**SKI** · 07-16-2003, 05:17 PM

Quote:

Originally posted by haven
I thought I read somewhere that a hub divides the speed among the active pc's, where a switch allows all conections to run a full speed. Is this true?

Actually, a hub allows just one PC at a time to transmit, at full speed. What they meant was that every PC has to share the available bandwidth, which is a little different.

Imagine a 1 lane, one-way street that you can drive 100kph on, but only one car can use at a time: that's the hub.

Now imagine a two-way multi-lane highway with room for a group of cars to drive @ 100kph at the same time (without running into each other): that's a full-duplex switch.

HTH

soulselekta · 07-16-2003, 05:36 PM

Wow. Very informative. Thank you! :eek:

zsaz1029 · 07-16-2003, 05:56 PM

Quote:

Originally posted by soulselekta
Wow. Very informative. Thank you! :eek:

I agree, thanks!!

We must have the very best Comms Moderator in all the internet!

**SKI** · 07-16-2003, 06:06 PM

Gee, thanks!

If you want to see the real hardcore people, though, check out the GroupStudy and Tek-Tips sites...

There are some pretty savvy people lurking around here too, as a matter of fact.

zsaz1029 · 07-16-2003, 06:54 PM

I'm in school right now studying various computer-related subjects, but don't yet know where I might go with it. Honestly, it's probably not going to be the network route.

07-15-2003, 02:01 PM	#1
soulselekta Registered User Join Date: Jul 2003 Location: Washington DC Posts: 23	Home Network Upgrade Currently I have 5 computers hooked to a hub which is hooked to a single port router, connected to a cable modem. This works fine for sharing the internet connection, but when sharing files (especially large ones) between computers, it's extremely slow (running at 10mbps, I'm being limited by some device, not the NIC's). I believe the cable is regular Cat5, so if I should upgrade to Cat5e, I'll do that. i've also been told that it's it the hub which is slowing everything down. I was considering just getting a 5 port switch similar to this one: Linksys Switch on Newegg So hopefully I could have all 5 pc's hooked into it and have the cable modem going into the uplink port. Would this be what I want to do? Thanks for the help! Edit: Also thinking about running freesco on one of the extra boxes to serve as a firewall if the switch doesn't offer that feature.
(Offline)

07-15-2003, 02:26 PM	#2
SKI Comms Moderator Join Date: Apr 2001 Location: Tempe, AZ (or wherever my luggage is) Posts: 8,487	Ideally, you want to retain your Router and buy a bigger switch. The 5-port linksys will actually only accomodate 4 PCs and the uplink to your 1 port router. It will also work if you run freesco on one box (5 PCs or 4 PCs + uplink to router), but then you'll need 2 nics in the freesco box, which you'd have to run full time as a router. Since you already own a router, I see no reason to dedicate resources on a PC to do the routers job. Also, to ensure 100Mbps you need to confirm that all your NICs can run at that speed. As for specific hardware, try this switch or this one. 8 ports, $45 for either... To recap, I'd just put an 8 port switch in place of your current hub. BTW, there's no reason to replace your cat5 with cat5e unless one or more of the current runs aren't in spec and don't support 100Mbps. In a commercial network I'd have the cable plant tested and certified before changing from 10Mbps to 100Mbps, but the cost is prohibitive for a home network. The easiest way to go is to hook up the new hardware, try to run @ 100, and replace any cable runs where you can't get to 100Mbps. HTH __________________ Never try to teach a pig to sing... It wastes your time, and annoys the pig.
(Offline)

07-15-2003, 04:14 PM	#3
soulselekta Registered User Join Date: Jul 2003 Location: Washington DC Posts: 23	I'm ordering the Linksys switch today, thanks for the help!
(Offline)

07-16-2003, 03:15 PM	#4
soulselekta Registered User Join Date: Jul 2003 Location: Washington DC Posts: 23	Out of curiousity.. what's the difference between a hub and a switch? Besides the increase in speed, are there any other advantages?
(Offline)

07-16-2003, 04:25 PM	#5
SKI Comms Moderator Join Date: Apr 2001 Location: Tempe, AZ (or wherever my luggage is) Posts: 8,487	Simply stated: a hub works like an old-fashioned telephone party-line. Everyone can hear everything, and only one person can talk at a time (or nobody can tell who's saying what). A switch is more like our modern telephones. Connections are established between specific devices, and everybody can call someone else and talk at once without coufusion. There's more to it than that, but that's the meat of the issue: you wind up with more effective bandwidth even given equal speed. And now, for those of you with time on your hands, here's a little more detail... Hubs create a shared connection. Anything that goes in a port is sent out all other ports (called flooding), so every other NIC has to decide if every packet is intended for it. This consumes some resources on every PC connected to the hub. Further, with a hub/shared media, two PCs can send traffic at the same time, creating a digital collision and requiring both PCs to resend that data. Only one PC at a time can transmit when you're using a hub. Technically this is called half/duplex communication, and the mechanism that Ethernet uses to handle this is referred to as CSMA/CD (carrier sense multiple access/collision detection). So yes, there are more disadvantages to a hub than just raw speed. BTW, there are 100Mbps hubs in existance, but the cost is unreasonable when compared to unmanaged switches like the one you're ordering. Switches are more sophisticated. When traffic comes into a switch port, the switch takes note of the sending and destination NICs MAC addresses (by reading them off the data packet) and enters sending MAC address into a table relating known MAC addresses to switch ports. If the switch doesn't have the destination MAC address in its table, it floods the traffic out all ports. If the switch has an entry, it sends the traffic out just the port that relates to the known destination MAC address. This drastically reduces LAN traffic volumn. Switches are also (in general) capable of supporting full-duplex communication. This allows PCs to both transmit and receive packets at the same time. The switches ability to learn MAC addresses allows it to go one step further than just reducing traffic: by relating just two ports to a particular data "conversation" it constructs a dedicated link between the two PCs involved. This uses a second pair of wires in the Ethernet cable and allows the PC on each end to send and receive traffic at the same time. Notice that with such a dedicated two-way link you've just virtually eliminated collisions. This is referred to as full-duplex Ethernet communication, and in fact the CSMA/CD mechanism is disabled, which reduces communications process overhead and speeds throughput. This feature is why some switch manufacturers advertise "speeds up to 200Mbps" for what is by definition a 100Mbps full-duplex switch: they mean 100Mbps in each direction at the same time. Any occasional collisions that occur are dealt with via software in what's referred to as the "upper layers" of the communications stack. Finally, there is the matter of range. A hub has a fixed 100 meter range, PC to hub. So does a switch in half/duplex mode: this is a timing component of CSMA/CD, intended to prevent what are referred to as "late collisions". When you convert to full-duplex communications, you turn off CSMA/CD and thus the limitation on overall distance is now 100 meters FROM DEVICE TO DEVICE, and the practical limitation becomes how good your wiring is, interference, and how good the hardware is at regenerating signals (which is another function of both switches and powered, or "active" hubs). In this scenario you can put, say, 3 switches between two PCs, and with 100 meters between each device you've just spanned 400 meters. Usually this sort of thing goes on only in very large buildings. Between buildings (and over long runs in general) it's advisable to use fiber links due to electrical safety and other issues. I could go on and on... there are a lot more things you can do with switches that just don't work with hubs... See what curiosity gets you? __________________ Never try to teach a pig to sing... It wastes your time, and annoys the pig.
(Offline)

07-16-2003, 04:35 PM	#6
GreyFox Registered User Join Date: Sep 2002 Location: Lurking In Front of the Monitor Posts: 231	I thought I read somewhere that a hub divides the speed among the active pc's, where a switch allows all conections to run a full speed. Is this true?
(Offline)

07-16-2003, 05:07 PM	#8
SKI Comms Moderator Join Date: Apr 2001 Location: Tempe, AZ (or wherever my luggage is) Posts: 8,487	With managed switches you can do things like: Create Virtual LANS (VLANS) independent of physical proximity Manage redundant LAN links for reliability (Spanning Tree Protocol) Create multi-link traffic paths for increased link capacity (port channels, generally on trunk links) and multi-VLAN trafic paths (VLAN trunking) Improve routing performance using multi-layer switching (also handy for ToS/QoS issues). Think switching at layer three and layer four rather than routing, although things get realy blurry here Implement security policies (Port security based on static or dynamic MAC address learning, and by limiting the number of MAC adresses that the port will accept) Can you say "CCNP"? If you REALLY want to freak out, take a look at MPLS (Multi-Protocol Label Switching)! I'm still working on this one... __________________ Never try to teach a pig to sing... It wastes your time, and annoys the pig.
(Offline)

07-16-2003, 05:36 PM	#10
soulselekta Registered User Join Date: Jul 2003 Location: Washington DC Posts: 23	Wow. Very informative. Thank you! :eek:
(Offline)

07-16-2003, 06:06 PM	#12
SKI Comms Moderator Join Date: Apr 2001 Location: Tempe, AZ (or wherever my luggage is) Posts: 8,487	Gee, thanks! If you want to see the real hardcore people, though, check out the GroupStudy and Tek-Tips sites... There are some pretty savvy people lurking around here too, as a matter of fact. __________________ Never try to teach a pig to sing... It wastes your time, and annoys the pig.
(Offline)

07-16-2003, 06:54 PM	#13
zsaz1029 Registered User Join Date: Mar 2003 Posts: 2,013	I'm in school right now studying various computer-related subjects, but don't yet know where I might go with it. Honestly, it's probably not going to be the network route. __________________ Spaz ----- "Those who would sacrifice liberty for security deserve neither." -- paraphrased from Benjamin Franklin. ----- Move into my city! Spaztowne Improve my city's streets! Click here! Open a factory in my city! Click here!
(Offline)

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode