Is gigabit LAN possible w/ gigabit switch + megabit router?

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PartEleven
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Is gigabit LAN possible w/ gigabit switch + megabit router?

Post by PartEleven » Tue Aug 25, 2009 9:19 am

I'm new to networking, so I'm hoping someone more knowledgeable could help. Currently, my network looks like this:

DSL modem -> 10/100 router --> many devices (PCs, PS3, notebook, wii)

Since I have a mix of megabit and gigabit enabled devices, I was wondering if it was possible to upgrade my network so that the gigabit devices can see and transfer to each other at gigabit speeds while maintaining internet access. I was thinking of something like:

DLS modem -> 10/100 router --> 10/100 devices + gigabit switch --> gigabit devices

Would this achieve what I want?

nutball
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Post by nutball » Tue Aug 25, 2009 9:55 am

Would this achieve what I want?
Yes. Your configuration is very similar to mine which works fine. Ethernet devices will auto-negotiate the best transfer speed between themselves and use that best speed on a case-by-case basis.

idale
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Post by idale » Tue Aug 25, 2009 10:30 am

With a switch, the connection is completely point-to-point, and so if both ends support gigabit (and the switch does, too, of course), then you'll get gigabit. So you can actually hook all your devices up to the switch and still maintain gigabit ability between the gigabit devices. In case that makes your networking change easier. 8)

PartEleven
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Post by PartEleven » Tue Aug 25, 2009 11:07 am

And I can still maintain internet access while connected to the switch? How would the router know that there is a switch with multiple devices attached to one of its ports? What settings do I have to change?

idale
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Post by idale » Tue Aug 25, 2009 11:48 am

PartEleven wrote:And I can still maintain internet access while connected to the switch? How would the router know that there is a switch with multiple devices attached to one of its ports? What settings do I have to change?
Yep, everything will work exactly as it does now. And there's nothing special you need to do, as switches (there's a switch in your router, too) will "learn" what devices are where on its ports, and handle sending packets where they need to go on their own. Just hook the parts together the right way and it'll all work out of the box. 8)

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Post by piglover » Tue Aug 25, 2009 12:08 pm

Yes, what you propose will work exactly as you plan. It is exactly the way my network is built today. Most Gigabit switches will also auto negotiate link speeds for each port, so you really don't need to worry about what devices you connect to it (i.e., feel free to connect you Wii to the gigabit switch if it is convenient for you). You just need to ensure that all of the gigabit capable devices are connected to the gigabit switch.

dhanson865
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Post by dhanson865 » Tue Aug 25, 2009 1:29 pm

I'd state your desired state as

DLS modem -> 10/100 router --> gigabit switch --> gigabit devices + 10/100 devices

or in other words plug your 100 mbit devices into the gigabit switch assuming you have no shortage of open jacks.

Your router might be limited to 10/100 on it's ports but there is no reason to segregate the 100 megabit devices onto it instead of plugging into the gigabit switch.

In rare cases you might have a 10mbit device that won't play nice with the gigabit switch that forces you to plug it into the 10/100 port but it'd have to be something super old.

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Post by Jay_S » Tue Aug 25, 2009 1:57 pm

http://www.newegg.com/Product/Product.a ... 6833156251

For about the same price, your can get the excellent Trend TEG-S80g 8-port unmanaged "Green" switch. I've read too many horror stories about the budget D-link, Netgear, etc. GigE switches.

I own a TEG-S80g and love it.

PartEleven
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Post by PartEleven » Tue Aug 25, 2009 3:03 pm

Thanks. I was deciding between the TRENDnet and the D-link. I've always thought D-link was be a better brand than TRENDnet though, since it's got some very well received higher end routers. With all of the networking brands, every one of them has a budget priced product that I've read complaints about. Anyway, I went with the D-link (bought from newegg with the 10% Bing cashback!) because of several great reviews from Amazon reviewers who know what they are doing and the lower price.

Still a few questions though:

1) Why is it better for me to plug everything into the gigabit switch? Would the megabit devices not show up on the local network if they were plugged into the router instead? If this is true then that's a bummer, since I have a few laptops connected through WAN that I'd like to still network as well.

2) What's the benefit to buying a native gigabit router then? From what I've learned here it seems amazingly easy to upgrade your existing network. And if you're starting from scratch it still seems cheaper to buy a megabit router + gigabit switch. Gigabit routers are typically $80+ even when on sale.

idale
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Post by idale » Tue Aug 25, 2009 3:21 pm

PartEleven wrote:1) Why is it better for me to plug everything into the gigabit switch? Would the megabit devices not show up on the local network if they were plugged into the router instead? If this is true then that's a bummer, since I have a few laptops connected through WAN that I'd like to still network as well.
You can plug devices into both the router and the switch and they'll be on the same LAN (you can think of the switch like a "power strip" sort of thing, just extending Ethernet ports instead of power outlets). Putting them all on the switch tends to be more for ease of use than anything.
2) What's the benefit to buying a native gigabit router then? From what I've learned here it seems amazingly easy to upgrade your existing network. And if you're starting from scratch it still seems cheaper to buy a megabit router + gigabit switch. Gigabit routers are typically $80+ even when on sale.
A multi-port router is just a router with a switch attached (internally), so there's not a particular difference between a 100Mb and 1Gb router, other than having a gigabit router means that you may not need an extra switch.

Though there's some market segmentation differences, too, as many companies can "bundle" the gigabit switching and higher-end features so you have to get them all together, so sometimes you'll get a gigabit router for the other features and not the speed itself.

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Post by Jay_S » Tue Aug 25, 2009 4:02 pm

PartEleven wrote:With all of the networking brands, every one of them has a budget priced product that I've read complaints about.
So true. It's kinda funny reading amazon and newegg reviews ("It's the best" ... "Total POS" ... "It's the best"...). The metal chassis, 5W power consumption, 8k jumbo support, and 5-year warranty sold me on the Trend switch.

Good luck with the D-Link. Most of the complaints I remember seeing on it were related to overheating issues. You could always do what this guy did - cable tie a heat sink to the processor!.
PartEleven wrote:Why is it better for me to plug everything into the gigabit switch?
It's not necessarily better, but it may simplify cable management to have everything patch through your switch. My home network is similar to yours:

DSL modem -> Router/Wireless Access Point/4-port 100Mb/s Swtich -> 8-port GigE switch

I have two devices that only have 10/100 NICs, and to save gigE ports they are plugged into my 100Mb router.

Some basic networking concepts may help you understand what's going on with these devices. What you are calling your router is (at least) three devices in a single chassis: router, wireless access point, switch. These interact to various degrees depending on the nature of the network traffic. Simplifying things a bit, for network traffic that doesn't leave your LAN, the router portion of this device doesn't do anything (aside from initial DHCP assignment). It's not routing unless traffic needs to leave your LAN.

Local traffic is all switched. Switching relies on hardware MAC addresses. Switches build tables of MAC addresses as they learn them from attached devices, so that they know which port to send data out of. Switches can connect to other switches and will "see through" each other to learn MAC addresses of more distant devices (there are limits to this).

Your router/WAP/switch gets cabled to the gigE switch (pick 1 of its LAN ports), and they share MAC addresses with each other. So, you can connect devices to both your gigE switch and your router/access pt/switch and all attached devices will be on the same LAN.
PartEleven wrote:Would the megabit devices not show up on the local network if they were plugged into the router instead? If this is true then that's a bummer, since I have a few laptops connected through WAN that I'd like to still network as well.
Through WAN (wide area network)? Or wireless? If wireless, then no problem - see above. The wireless access point in your router is connected to its internal switch and will be on the same LAN.
PartEleven wrote:What's the benefit to buying a native gigabit router then? From what I've learned here it seems amazingly easy to upgrade your existing network. And if you're starting from scratch it still seems cheaper to buy a megabit router + gigabit switch. Gigabit routers are typically $80+ even when on sale.
I assume you're talking about multi-function router/WAP/switches with gigE LAN switch ports, and not gigE WAN port(s). Someone might be short on desk space and have a small number of wired devices. Having a single gigE router instead of separate router + switch would save on desk space and power outlet wall-wart space. But I agree with your general idea - there's really no NEED for a gigE router. Possibly once wireless bandwidth exceeds 100Mb, though.

[EDIT] I see idale beat me to it!

dhanson865
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Post by dhanson865 » Wed Aug 26, 2009 2:22 pm

PartEleven wrote: 1) Why is it better for me to plug everything into the gigabit switch? Would the megabit devices not show up on the local network if they were plugged into the router instead? If this is true then that's a bummer, since I have a few laptops connected through WAN that I'd like to still network as well.

2) What's the benefit to buying a native gigabit router then? From what I've learned here it seems amazingly easy to upgrade your existing network. And if you're starting from scratch it still seems cheaper to buy a megabit router + gigabit switch. Gigabit routers are typically $80+ even when on sale.
1a. If you decide to power down the router or power cycle it you won't kill the connection between other devices on your "internal" network.

1b. You don't have to think about the speed of the device the gigabit switch will autodetect and run at 1000 or 100 as needed

1c. You may be able to use shorter cables (extreme edge case) if say the gigabit switch is closer to another end user device than the router is.

2a. Until your WAN connection (aka whatever your ISP gives you) gets to be greater than 60MB/s* you don't gain anything by getting a Gigabit router if you already own a gigabit switch. However if you only have 2 or 3 devices then the 4 or 5 ports on a router/switch might be enough for you and save you desk space / shelf space / power strip space / electricity / etcetera by not having a separate device sitting around powered on.

Since I'm still on a cable modem that gives me less than 10mb down and well less than that on the upstream I don't expect to be worrying about the port speed on my home switches. I don't do enough PC to PC traffic with large transfers to care that I'm on a 100 Mbit network at home.

*on the 60 MB/s number I'm pulling that out of my foggy memory and rounding liberally. I think it is based on tests I read about months ago before buying new switches for work the last time I needed to buy some.

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Post by piglover » Wed Aug 26, 2009 2:38 pm

dhanson865 wrote:
PartEleven wrote: ...Since I'm still on a cable modem that gives me less than 10mb down and well less than that on the upstream I don't expect to be worrying about the port speed on my home switches. I don't do enough PC to PC traffic with large transfers to care that I'm on a 100 Mbit network at home...
But you will care! It will happen on the very same day that you buy a small NAS or WHS box for backups or media streaming!

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Post by PartEleven » Wed Aug 26, 2009 5:15 pm

Thanks for the tips guys.
Jay_S wrote:Through WAN (wide area network)? Or wireless?
I meant wireless. I guess the correct term is "WLAN".
dhanson865 wrote:1a. If you decide to power down the router or power cycle it you won't kill the connection between other devices on your "internal" network.
That's a really good point. I haven't really encountered a situation where this could matter yet, but it's handy to be able to power cycle the router while streaming a movie.
piglover wrote:But you will care! It will happen on the very same day that you buy a small NAS or WHS box for backups or media streaming!
Meh, I guess it depends on your usage. I already have a server-ish system set up on my network, and the network speeds didn't really bother me much. I'd just set up a transfer and walk away, or switch to my laptop. Actually my main motivation for upgrading was because I am out of ports. If I'm going to have to buy an extra device, might as well make it gigabit right? ^ ^

EDIT: So the switch arrived tonight and I hooked everything up. I did some quick transfers to see what kind of speeds I get, and I'm only getting ~20-30 MB/sec. It's definitely faster than megabit ethernet, but it seems much slower than it could potentially be. I have no idea what I should be looking at to see where's the bottleneck. My network chipsets? cables? drivers?

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Post by theycallmebruce » Wed Aug 26, 2009 7:01 pm

More than likely your disks and the inefficiencies of Windows file sharing.

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Post by Riffer » Thu Aug 27, 2009 7:07 am

You might just want to replace you router with a gigabit one. the 100 stuff will still operate at 100, and your gigabit devices will still transfer at gigabit speeds. Simplifies cabling, but it may cost a bit more.

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Post by Jay_S » Thu Aug 27, 2009 12:35 pm

Edited:
theycallmebruce wrote:More than likely your disks and the inefficiencies of all file sharing protocols.
This is a real shock to everyone upgrading to a gigabit network. It was certainly shocking to me. "Why don't I get 125 MB/s transfers?" Even if you accept a reasonable amount of protocol overhead (20%?), it's hard to get 100MB/s network transfers without really fast disk subsystems on both ends.

The "How to Build a Really Fast NAS" series over at smallnetbuilder.com is a terrific introduction to DIY network storage, and illustrates how difficult it is to get 100MB/s performance.

The bottle neck hunt should begin with your drives. Get familiar with iozone. Here's a how-to. Unless you're transferring really small files, your drives' ability to get data physically on/off their platters will be the ultimate speed limitation.

You can use jperf (iperf with a java GUI) to conduct raw TCP stream tests between NIC transceivers. This will confirm your cables and switch are not your bottleneck (tip with WinXP: set TCP window size to 64k). You should see TCP stream speeds in the upper 900 Mb/s range.

Ultimately, SMB isn't very efficient protocol. Apparently SMB2 (in vista and server 2008) brings a performance increase, but I don't use either OS's and can't comment. FTP is fast, but not as convenient as SMB. I don't have any experience with NFS, iSCSI, or anything esoteric.

PartEleven
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Post by PartEleven » Fri Aug 28, 2009 7:18 am

Thanks for the links Jay_S. Of course I wasn't expecting anything like 125MB/s. My older hard drives don't even transfer that fast between themselves locally. I was expecting something in the 45-50 mb/s range though, so I found it surprising to see my transfers dipping down to 25 mb/s.

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Post by Lockheed » Fri Aug 28, 2009 10:29 am

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Post by Jay_S » Fri Aug 28, 2009 11:40 am

Lockheed wrote:I get about 45MB/sec write and 67MB/sec read with SMB over my gigabit network.
Those are respectable single-drive numbers. How are you measuring this?

I average ~ 45MB/s reads with my WD10EADS via SMB with large file sizes (2GB+). My writes are horrendous (in the low 20's), but that's a "feature" of unRAID ;).

One of my favorite aspects of smallnetbuilder.com is that they have a very well defined and documented test methodology. Their forums are a great resource as well - there's a DIY section with a few very helpful and active members.

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Post by Lockheed » Tue Sep 01, 2009 12:09 pm

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theycallmebruce
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Post by theycallmebruce » Tue Sep 01, 2009 8:45 pm

Near wire-speed throughput is achievable if your disks are up to it. I have measured almost 2 gigabit per second, full duplex, using a pair of HP PCI Express dual-port Ethernet adapters.

This was measured with a standard disk benchmarking tool under Windows XP. The "disk" was a 6 Gigabyte RAM disk on a Linux machine, connected using ATAoE (ATA over Ethernet), and jumbo (8000 byte) Ethernet frames.

Basically ATAoE just wraps standard ATA commands in raw Ethernet frames. Compared with protocols which run on top of TCP/IP, this is very efficient. It is conceptually similar to iSCSI (but with a simpler spec, less overhead, and a free client driver for Windows which supports network booting).

theycallmebruce
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Post by theycallmebruce » Tue Sep 01, 2009 8:50 pm

Near wire-speed throughput is achievable if your disks are up to it. I have measured almost 2 gigabit per second, full duplex, using a pair of HP PCI Express dual-port Ethernet adapters.

This was measured with a standard disk benchmarking tool under Windows XP. The "disk" was a 6 Gigabyte RAM disk on a Linux machine, connected using ATAoE (ATA over Ethernet), and jumbo (8000 byte) Ethernet frames.

Basically ATAoE just wraps standard ATA commands in raw Ethernet frames. Compared with protocols which run on top of TCP/IP, this is very efficient. It is conceptually similar to iSCSI (but with a simpler spec, less overhead, and a free client driver for Windows which supports network booting).

theycallmebruce
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Post by theycallmebruce » Tue Sep 01, 2009 8:51 pm

Near wire-speed throughput is achievable if your disks are up to it. I have measured almost 2 gigabit per second, full duplex, using a pair of HP PCI Express dual-port Ethernet adapters.

This was measured with a standard disk benchmarking tool under Windows XP. The "disk" was a 6 Gigabyte RAM disk on a Linux machine, connected using ATAoE (ATA over Ethernet), and jumbo (8000 byte) Ethernet frames.

Basically ATAoE just wraps standard ATA commands in raw Ethernet frames. Compared with protocols which run on top of TCP/IP, this is very efficient. It is conceptually similar to iSCSI (but with a simpler spec, less overhead, and a free client driver for Windows which supports network booting).

theycallmebruce
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Post by theycallmebruce » Tue Sep 01, 2009 8:51 pm

Near wire-speed throughput is achievable if your disks are up to it. I have measured almost 2 gigabit per second, full duplex, using a pair of HP PCI Express dual-port Ethernet adapters.

This was measured with a standard disk benchmarking tool under Windows XP. The "disk" was a 6 Gigabyte RAM disk on a Linux machine, connected using ATAoE (ATA over Ethernet), and jumbo (8000 byte) Ethernet frames.

Basically ATAoE just wraps standard ATA commands in raw Ethernet frames. Compared with protocols which run on top of TCP/IP, this is very efficient. It is conceptually similar to iSCSI (but with a simpler spec, less overhead, and a free client driver for Windows which supports network booting).

theycallmebruce
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Post by theycallmebruce » Tue Sep 01, 2009 8:52 pm

Near wire-speed throughput is achievable if your disks are up to it. I have measured almost 2 gigabit per second, full duplex, using a pair of HP PCI Express dual-port Ethernet adapters.

This was measured with a standard disk benchmarking tool under Windows XP. The "disk" was a 6 Gigabyte RAM disk on a Linux machine, connected using ATAoE (ATA over Ethernet), and jumbo (8000 byte) Ethernet frames.

Basically ATAoE just wraps standard ATA commands in raw Ethernet frames. Compared with protocols which run on top of TCP/IP, this is very efficient. It is conceptually similar to iSCSI (but with a simpler spec, less overhead, and a free client driver for Windows which supports network booting).

theycallmebruce
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Post by theycallmebruce » Tue Sep 01, 2009 8:58 pm

Um. Sorry folks. Can't seem to delete the duplicate posts either.

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