jeremymacmull

Gigabit Switches

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Okay here is the thing ive wanted to have a gigabit ethernet network for some time now

all the computers have gigabit ethernet capability and after looking at the prices of some switches i thought why not

the computers are

1 X A64 3200 with 160 gb (2X hitachis 7K250 in Raid 0) (2X 160 gb Hitachis in RAID 0 ) with and onboard gigabit network interface on asus K8V deluxe

1X A64 3400 with onboard Gigabit network interface with (2X samsung spinpoint 80 gb in RAiD 0) ASUS K8V deluxe

1X P4 3.2 with HT (1 X 74 gb raptor ) & (2X 7K250 80 gb in RAID 0) INTEL 875p chipset with CSA for ethernet

all the files pretty much that i want to move about are single large files ie more than 4000 mb often dvd size (dvd images to be exact) so i included disk setups as i thought in this case linear sequentual read and write performance could become a bottle neck due to the fact that im copying large files from pc A to pc b and c. i stress these are my mates computers and we live in a shared house so i dont really want a discussion about advantages etc etc of RAID 0 at all. all the raid systems can do 80 mb sec according to bechmarks so they should be able to get the maximum thruput without being disk limited too much

ive already got cat 5 e cabling in place although at the moment im using a linksys bef8r1 router and switch combo attached to my cable modem. which limits us to 100mbit speeds i was going to buy one of these gigabit swtiches and place all our computers on it after attaching it to the router to keep the internet connection

i know ill have a speed up in file transfers and i know what to realistically expect as a minimum but i was hoping with RAID 0 and the serial nature of large file transfers i would like to maximise that speed possibility by choosing the best switch for the money

the reason i ask questions is all the switches are very similiar in price and there are two from linksys and i cant tell the difference between em at all just the 5 pound diff in price and different shape!!??

OK ive blabbed on enough here are my choices of switches

1) D-Link DGS-1005D 5-Port GigaExpress Switch 51 pounds

2) Linksys EG005W Gigabit 5-Port Switch 62 pounds

3) Linksys SD2005 5-Port Gigabit Switch 66 pounds (2 and 3 are the ones i cant tell the difference from and linksys are my preferred manufacturer but if there is a marked difference in speed then im willing to use another)

4) Netgear GS105 5 Port Gigabit Switch 55 pounds

5) US Robotics USR997930 8-Port Gigabit 60 pounds

6) Asus GigaX 1105 Gigabit Switch 43 pounds

ok thats it the price difference is inconsequential as at most its only about 10 to 20 pounds and im quite willing to spend the 66 pounds of the most expensive one so im not interested in that comparison. the only thing id like is a pure performance comparison

all those with experience with these switches pls contribute it would be appreciated

ive looked up reviews and benchmarks for the linksys EG005W switch and they say wildly different things on has a transfer of 49 mb sec other has 29 etc etc

JEREMY

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I would go with the Linksys, I don't know the difference between the 2 models but I've had and heard more positives about linksys then the other brands.

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um ok see i was biased towards linksys anyways

as for the other replys um not really much help :(

dont really care if it looks cool and the specs dont seem to say about jumbo frames and i was hoping someone had some real world experience with using gigabit switches to be able to comment for me

hopefully on these models

also why kinda of transfer rates am i likely to get between the pcs as listed some sites say up to 80 mb sec others say about 29 big difference and that is the only one i could find reviewer the linksys cheaper switch and it did not say a thing about jumbo frames or otherwise

sorry still need help

JEREMY

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Get SMC's gigabit switch. It is the only low-cost switch to support gigabit frames.

Note that all other devices connected to the switch must also support gigabit frames, or the entire network is degraded to regular frame sizes. Most gigabit NICs support them just fine.

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cheers silvar for the suggestion but thats not a switch available to me

the ones i have a choice of are listed above

does anyone know if any of them do gigabit ethernet jumbo frames and if the computers attached to them do it

JEREMY

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I believe all the switches you name don't support jumbo frames. The SMC is the only cheap switch to date that does. I think that if I were you, I would try and make the SMC switch available to you. I have one and I love it! You also don't have to make everything on the switch support jumbo frames. I have 10mbit half duplex print servers attached the the switch and it work just fine when all my computer have jumbo frames on. With Jumbo frame off I only get about 20MB/s transfers between computers. With Jumbo frames on I get 30MB/s transfers. Jumbo frames also lower my CPU usage. With Jumbo frames on the CPU never get over 40%. With Jumbo frames off the CPU usage is 100%. Almost all gigabit cards support jumbo frames, so if I were you I would make sure you get a switch that supports jumbo frames.

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You definetely need to get a jumbo frame supporting switch. Since you want to do file copies, this is ESSENTIAL for you. W/O jumbo frames, you will only get a modest -if at all- improvement. All your NIC should support it anyway.

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thanks for the replys

do the intergrated gigabit ethernet options on these motherboards support jumbo frames

cos its useless me looking for a switch if the network interfaces dont support it

also if i get one of these switches which do not support jumbo frames what likely speeds am i possibly going to see with my current setup for copying large files 4 gb Plus in size to pc A to Pc b and c

20 mb/sec ? 30mb/sec more ????? etc

thanks for the replys

PS ive never even heard of SMC

if someone has a UK outlet that sells these switches pls let me know also if u could let me know the price of such thing

JEREMY

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Jeremy I just gleaned these SMC links from a previous discussion here.

5 port model : SMC8505T

http://www.buy.com/retail/product.asp?sku=...2103&dcaid=1688

$50

8 port model :

http://www.buy.com/retail/product.asp?sku=...30&loc=&rp=true

$100

Both handle the Jumbo frames which one should be looking for and I don't believe is supported in the switches listed above.

thanks for the replys

do the intergrated gigabit ethernet options on these motherboards support jumbo frames

cos its useless me looking for a switch if the network interfaces dont support it

also if i get one of these switches which do not support jumbo frames what likely speeds am i possibly going to see with my current setup for copying large files 4 gb Plus in size to pc A to Pc b and c

20 mb/sec ? 30mb/sec more ????? etc

thanks for the replys

PS ive never even heard of SMC

if someone has a UK outlet that sells these switches pls let me know also if u could let me know the price of such thing

JEREMY

192162[/snapback]

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does anyone know if any of them do gigabit ethernet jumbo frames and if the computers attached to them do it

The nVidia nForce3 250-gb and nForce4 integrated ethernet support jumbo frames, if the motherboard uses the nVidia chipset-based ethernet. If it uses something else, it depends on the something else.

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Lets put it like this, I have never seen a gigabit nic not support jumbo frames. I've used Realteks, Broadcoms, Intels, Dlinks, Linksys, and all support Jumbo frames.

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I believe all the switches you name don't support jumbo frames.  The SMC is the only cheap switch to date that does.  I think that if I were you, I would  try and make the SMC switch available to you.  I have one and I love it!  You also don't have to make everything on the switch support jumbo frames.  I have 10mbit half duplex print servers attached the the switch and it work just fine when all my computer have jumbo frames on.  With Jumbo frame off I only get about 20MB/s transfers between computers.  With Jumbo frames on I get 30MB/s transfers.  Jumbo frames also lower my CPU usage.  With Jumbo frames on the CPU never get over 40%.  With Jumbo frames off the CPU usage is 100%.

192116[/snapback]

What's this? So, the theory saying that all your hooked up gear have to support jumbo frames is wrong? I thought you lost jumbo frame support on your switch as soon as you use regular MTU 1518 devices?

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I believe all the switches you name don't support jumbo frames.  The SMC is the only cheap switch to date that does.  I think that if I were you, I would  try and make the SMC switch available to you.  I have one and I love it!  You also don't have to make everything on the switch support jumbo frames.  I have 10mbit half duplex print servers attached the the switch and it work just fine when all my computer have jumbo frames on.  With Jumbo frame off I only get about 20MB/s transfers between computers.  With Jumbo frames on I get 30MB/s transfers.  Jumbo frames also lower my CPU usage.  With Jumbo frames on the CPU never get over 40%.  With Jumbo frames off the CPU usage is 100%.

192116[/snapback]

What's this? So, the theory saying that all your hooked up gear have to support jumbo frames is wrong? I thought you lost jumbo frame support on your switch as soon as you use regular MTU 1518 devices?

193543[/snapback]

In theory, since a switch is a point-to-point connection (unlike a hub), shouldn't the switch be able to handle a mix of frame types?

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Yes, you can mix them. But the frame sized should then downgrade to standard MTU value (1518). But obviously he claimed to receive higher performance while having jumbo frames enabled. I just thought it was strange... :blink:

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Will the CPU utilization decrease if you have jumbo frame enabled on the NIC, although your switch doesn't support it?

193554[/snapback]

In theory your CPU utilization should go to zero because there will be no data transfer...

Oh wait. What will actually happen, is that the NIC and the switch will negotiate their highest speed and will fall back to normal frames. Nope, no significant change in CPU utilization.

-- Rick

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1 X A64 3200 with 160 gb (2X hitachis 7K250 in Raid 0) (2X 160 gb Hitachis in RAID 0 ) with and onboard gigabit network interface on asus K8V deluxe

1X A64 3400 with onboard Gigabit network interface with (2X samsung spinpoint 80 gb in RAiD 0) ASUS K8V deluxe

Both these systems use PCI ethernet chips. This will limit performance to 30-40meg per sec.

1X P4 3.2 with HT (1 X 74 gb raptor ) & (2X 7K250 80 gb in RAID 0) INTEL 875p chipset with CSA for ethernet

This has the ethernet directly connected to the CSA network, and potentially can see much better performance.

all the files pretty much that i want to move about are single large files ie more than 4000 mb often dvd size (dvd images to be exact) so i included disk setups as i thought in this case linear sequentual read and write performance could become a bottle neck due to the fact that im copying large files from pc A to pc b and c. i stress these are my mates computers and we live in a shared house so i dont really want a discussion about advantages etc etc of RAID 0  at all. all the raid systems can do 80 mb sec according to bechmarks so they should be able to get the maximum thruput without being disk limited too much

With the PCI gigabit ethernet, you should not expect higher then 40mbyte per sec. It would be best to get the SMC switch.

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I got 8-port SMC switch mentioned above. Using TTCP it seems I hit the limit of PCI bus for network transfer. Doing the file copy I move 4.5 GB DVD image from one PC to another in 2.5 min vs 7.5 min in 100Mbit mode. Jumbo frames are off.

I am under impression that not all onboard Gigabit NICs support Jumbo frames. At work I have Dell PowerEdge 400SC and it has this option in Advanced setup for the network adapter, at home I have Dell Dimension 8400 - and it doesn't seem to have this option available via UI.

However, I returned this SMC switch b/c it was making high-pitched sound that was driving me nuts. I also didn't like that cables connect in the front - turned out to be inconvenient on the desk for me. If your switch is on the wall I guess you don't care. I ordered D-Link gigabit switch instead (haven't gotten it yet).

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In theory, since a switch is a point-to-point connection (unlike a hub), shouldn't the switch be able to handle a mix of frame types?

193551[/snapback]

Yes, you can mix them. But the frame sized should then downgrade to standard MTU value (1518). But obviously he claimed to receive higher performance while having jumbo frames enabled. I just thought it was strange...  :blink:

193553[/snapback]

My understanding from previous discussions on this topic is that it's all or nothing for jumbo. The switch doesn't have the capability of breaking up the jumbo frames when forwarding them on to NICs that don't support it. And the NIC uses a constant frame size when sending data - it can't intelligently alter the frame size dependant on the recipient.

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However, I returned this SMC switch b/c it was making high-pitched sound that was driving me nuts.

193596[/snapback]

YUP!

The switch is junk in my opinion. Something inside emits a squeal around 14 to 15 KHz, and even my old ears can pick it up just fine.

Plus it did nothing for speed. I tried everything. Upgraded my NIC drivers, tried all the jumbo frame settings on the NICs. 500 to 0 KB/sec performance. It froze for a few minutes during several of the tries, but eventually let me shutdown. Each time it froze when attempting to copy files or explore folders for files to copy. One time it locked hard and I had to hit the reset button. Which is all terrible because then my 3Ware RAID 10 array spends 4 hours resyncing.. glacially slow performance during.

Hardware is decent- Supermicro P4SCT+II (file server) and X5DAL-G (workstation). Windows 2000 on both. Tried several brands of Cat5e and Cat6 cables.

At work this week we upgraded to several $5000 Cisco 48 port managed switches. Don't recall the model but for $5000 per you'd think jumbo would work. No lockups, but very long browse times (1 to 2 minutes) and 500 KB/sec performance when copying files. Tried all the block permutations. We're going to try upgrading the drivers soon. Recent HP and Dell servers. Plus to keep working, we've locked down the NICs to 100 Mbps. They won't even work at GIG-E minus jumbo (got 500 KB/sec still). New Cat5e cables.

Why is this so difficult to get working?

Has anyone actually got jumbo to work, and if so, what model switch and NICs (chipset please if onboard), switch and NICs settings, and brand cables?

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My understanding from previous discussions on this topic is that it's all or nothing for jumbo.  The switch doesn't have the capability of breaking up the jumbo frames when forwarding them on to NICs that don't support it.  And the NIC uses a constant frame size when sending data - it can't intelligently alter the frame size dependant on the recipient.

193600[/snapback]

What I'm suggesting is that since TCP/IP requires a handshake prior to operation, one could arrange matters so that the packet size is the best available prior to data transfer from one NIC to another via the switch. Ergo, a network could exist with both jumbo and non-jumbo frames. This is theoretically possible; I just don't know if it's practical or warranted.

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My understanding from previous discussions on this topic is that it's all or nothing for jumbo.  The switch doesn't have the capability of breaking up the jumbo frames when forwarding them on to NICs that don't support it.  And the NIC uses a constant frame size when sending data - it can't intelligently alter the frame size dependant on the recipient.

193600[/snapback]

What I'm suggesting is that since TCP/IP requires a handshake prior to operation, one could arrange matters so that the packet size is the best available prior to data transfer from one NIC to another via the switch. Ergo, a network could exist with both jumbo and non-jumbo frames. This is theoretically possible; I just don't know if it's practical or warranted.

193635[/snapback]

I plan on trying a switch that can jumbo, not jumbo and 100 all at once. I'll let you all know how it works after it gets up and ready.

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My understanding from previous discussions on this topic is that it's all or nothing for jumbo.  The switch doesn't have the capability of breaking up the jumbo frames when forwarding them on to NICs that don't support it.  And the NIC uses a constant frame size when sending data - it can't intelligently alter the frame size dependant on the recipient.

193600[/snapback]

What I'm suggesting is that since TCP/IP requires a handshake prior to operation, one could arrange matters so that the packet size is the best available prior to data transfer from one NIC to another via the switch. Ergo, a network could exist with both jumbo and non-jumbo frames. This is theoretically possible; I just don't know if it's practical or warranted.

193635[/snapback]

I think the problem is that frame size is a functionality of a lower level of the network model than TCP/IP. So the entire local LAN must be operating in either jumbo or non-jumbo mode, because even if the sending NIC could query the receiving NIC to check for jumbo capability (which would happen at the driver level), there's no guarantee or method to check the entire network path to the receiver supports jumbo. At least that's my understanding of why you can't mix jumbo and non-jumbo on a normal, single LAN.

Maybe you could use VLAN technology to get around this problem, but there's no consumer level switches that support both jumbo and VLAN. Or you could use a switch or router that operates at a higher level.

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