Jump to content

GigE network setup - quick question


Zxian
 Share

Recommended Posts

I'm just wondering about my future network that I'm hoping to setup. I'd like to use gigabit ethernet for the wired network, but I'm happy with 802.11g for wireless, since that's what all my wireless computers use, and there aren't any major problems yet.

I've got a WRT54GL, which I absolutely love, because of the stability and setup. I was hoping that I could add a gigabit switch to the network, and have the GigE devices connected to it. Would I be loosing all benefit of GigE because it's controlled by a 100Mbps device?

Also - does a GigE network suffer from the same overall slowdown that wireless suffers from a mixed B/G network?

Link to comment
Share on other sites


The only thing that would be limited is whatever is connected to the wireless. Not only that, but the speed is further limited by the inherent slowness of wireless anyway. So you wouldn't see much change now, but you are future proofing your network.

Link to comment
Share on other sites

the best thing to do would be to connect a gig switch to the switch on the router and plug any devices into this, nothing that passes through that switch to the internet will be limited by the 100mpbs of the router, and everything plugged into the gig switch will run at 1gbps. problem solved! :)

Link to comment
Share on other sites

I guess what I'm asking is where the packets themsevles travel to/from in a situation where you have

ISP--ROUTER--SWITCH--COMPUTER1
\--COMPUTER2

if you understand my diagram.... ;)

If I'm sharing files between the two comptuers, does any traffic go to the router? The router-switch speed would be limited to 100Mbps, so if traffic goes to/from the router, the "1Gbps" speed of the computers and the switch is completely negated.

I realize the wireless would be the slowest at the moment, but I'm hoping to make a fileserver, and I've already run into times where the network becomes a bottleneck transferring files to and fro.

Link to comment
Share on other sites

no, all that goes through the router with this setup is

ComputerX <-> WLAN

ComputerX <-> Internet

Traffic between the computers will not leave the Gigabit switch (if its not broadcasted).

Link to comment
Share on other sites

zxian, the reason none of your data will travel past the router or even to it is because the subnet mask will tell your computers that the other one they are trying to reach is on the same subnet. Therefore there is no need to go to the (router) default gateway in this case :)

like bj-kaiser mentions only broadcast will hit the router, but that will get dropped anyway as all routers (as far as i know) drop broadcasts, especially Lan to Wan

cheers :D

Link to comment
Share on other sites

  • 3 weeks later...

Just happened to be looking through Zxian's profile and came across this thread....

I've got the exact same setup you're looking at setting up. I have a Linksys WRT54GL router with a Netgear GS105 GigE switch attached to it. The cable modem is, of course, attached to the WAN port on the router. The Netgear uplink port is connected to port 1 of the router's switch. All of my wired computers have GigE NICs so they're connected to the GigE switch.

The additional network throughput was immediately noticeable when I first hooked up the GS105. Netgear makes (or used to anyway) a GigE switch that will stack perfectly on top of (or under) the WRT54G line of routers. That little Netgear switch gets HOT sometimes so you may want to look for something else. The only reason I got the Netgear is because Best Buy had them mis-marked @ $15! :thumbup

Also, just a little information...from what I've read neither the Netgear I have nor the Linksys models support jumbo frames in case that's a consideration for you. Again, $15 for a GigE switch was impossible to resist.

I'm actually thinking about replacing the GS105 with either a Dell PowerConnect 2708 (8-port web managed) or 2716 (16-port web managed). The prices on them are really good for psuedo managed switches.

Link to comment
Share on other sites

  • 2 months later...

So... a bump to this thread with a bit of an update.

As a foreword, I've been testing my network with two methods. First is by using a tool called iperf. You copy the executable to somewhere in your path (I put it under system32), and then run the following commands:

On the server:

iperf -s -D -w1m

On the client:

iperf -c <server_address> -w1m -i1 -t30

The -w switch is key - it sets the TCP window size to 1MB in this case. The default 8K window is simply too small to make use of a gigabit network. The second testing method is by copying files over a network share using TeraCopy. I typically used a 8MB buffer size, since I found that this often gave me the highest speeds.

I made sure to get devices that supported jumbo frames, since every document I've read indicates that 1500 byte frames are simply not enough for gigabit networks. To enable jumbo frames, you'll need to set this in the device properties page, as well as in the TCP stack. I followed the instructions found here, but used 513920 as the value for the TCP Window sizes (both regular and maximum).

I've got two new systems, both with gigabit, and both with crazy fast hard drive subsystems (as far as most computers go anyways :P). I had bought the Netgear GS605, which in the end turned out to be a piece of crap. Using iperf, I was getting about 700mbps on a good test. I swapped this for a DLink DGS-1005D and found that network performance was actually what it should have been - 990mbps. I managed to find another store that sold the DGS-1008D (the 8-port version of the same switch) for the same price, and speeds were the same.

With my TeraCopy testing, I copied files to/from my RAID0 (2xWD3200AAKS on ICH8R) array on my one system to my RAID5 (4xWD5000AAKS on 3ware 9650SE-8LPML) array on the other. Copying from the RAID5 to the RAID0, I'm disk limited by the write on my RAID0 array - I get about 75-80MB/s average speeds when copying a 1.4GB XviD rip. Going the other way I think I'm network limited, since I get about 110MB/s average transfer speed. Before anyone asks, yes, both drives are defragged regularly by PerfectDisk.

One last thing I noticed... transferring this much data requires quite a few CPU cycles. My file server (the one with the RAID5 setup) is based on an Intel E2160 CPU at stock speeds. When running the iperf test, the overall CPU usage was around 18%! Just a word of warning for others who might try this with a less powerful single CPU system - you might be limited by your CPU's capabilities.

Long story short - don't buy Netgear's "consumer" lineup, and make sure you've got jumbo frames enabled for maximum network throughput. :)

Link to comment
Share on other sites

Long story short - don't buy Netgear's "consumer" lineup, and make sure you've got jumbo frames enabled for maximum network throughput. :)

An Interesting story; I’m not surprised Netgear's "consumer" lineup doesn’t satisfy you, but I’m surprised that the ones from DLink did well for a low price.

For me there is only one brand and that is LinkSYS, from the SLM2005 and up.

I have now an 100Mbps network here but when I move from here I’ll go 1GiB as well. Did you use CAT5 or 6 by the way?

Link to comment
Share on other sites

@Punto - I used cat6 cables. I found that with Cat5e on the netgear box, it would occasionally drop me down to 100Mbps. I haven't bothered trying cat5e with the DLink switch.

@cluberti - I had also heard good things about the pro lineup of Netgear switches, but I didn't like how the power cord is on one side, and the ethernet jacks are on the other. That doesn't really lend itself to a clean layout.

Link to comment
Share on other sites

Hm - all of the network switching gear I've used from Netgear had power on the back and ports on the front, which is exactly what you'd want for cable management. Maybe I misunderstand - no matter though, as higher-end devices from almost any vendor will be good enough for demanding home / small business users.

Link to comment
Share on other sites

Right, we're talking about the same thing, but considering that my networking equipment is sitting on my desk, one of the two sides is going to be at the "front", leaving at least one cable poking out. I'd rather have all the plugs in the back, and status lights on the front (like traditional home routers mostly have), like you see below:

Networking_gear_thumb.jpg

Having a power cable or ethernet cables come out the front is slightly unfavorable, but if I were to install this in my basement or server room (which I plan on having one day... one day), then I'd probably go with something more like what you're talking about.

The bottom two devices are old networking equipment. Below my current WRT54GL, is a dead WRT54G v2.2. It's not bricked, but dead. The power light won't even show up. I had added a 60mm fan to it, and I think the whole thing died one day when I flicked the power switch... :blushing:

The bottom DLink switch is my old DSS-8+. It still works, and I figure I'll keep it around in case I ever run off to another LAN party in the area and someone needs an extra switch.

I personally find it a shame that Linksys changed the physical dimensions of their devices. It would have been really nice to find the modern equivalent to the EG008W (it didn't support jumbo frames) that would have fit underneath my WRT54GL. I just found it really slick how they stacked on top of each other so easily.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.


×
×
  • Create New...