Gig-E speeds for wired network behind old router

Clocker

Clocker

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Hi-
I have a 802.11g / 10/100 router I want to keep using (don't want 802.11n stuff until final ratification of the standard). But I want to gave gigabit speed between my main PC and my WHS box in my basement. What is the best/easiest/cheapest way to achieve that and maintain connectivity to the internet (via my router) for the WHS box? I already have CAT6 cable going to the WHS box. BTW, my cable company gives me up to 3 IPs if that makes a difference.

And, Happy Holidays!

Thanks,
C
 
ddrueding

ddrueding

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Based on my research (ie - not guaranteed to be accurate)

Get a basic GbE switch, connect it to your router, connect your GbE devices to the switch. This still won't utilize "Jumbo Frames", but it will be faster (at least mine was) between GbE devices. In order to use jumbo frames, you need some more intelligent hardware to bridge between, which was really expensive last I looked.
 
Clocker

Clocker

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Thanks.... any recommended brands?

BTW, the network adapters I'm using are as follows:

Main PC: Realtek RTL8111B Gigabit LAN (PCI-E onboard)

WHS box : Marvell Yukon 88E8053 PCI-E Gigabit Ethernet Controller

The WHS box also has another Yukon Gig-E controller in the PCI bus that is not currently utilized.
 
ddrueding

ddrueding

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Clocker said:
The WHS box also has another Yukon Gig-E controller in the PCI bus that is not currently utilized.
Click to expand...

I have been told that using both network ports on a computer by bridging them allows one side to run jumbo frames and the other side to not. If this is the case, and you only have the two devices to run GbE, you could just connect a crossover cable between the second GbE port on the server and your other GbE machine. Then enable bridging on the server and enable jumbo frames on the the two interfaces connected by crossover.

Of course, this is typically where the better informed members (Merc or Mark) correct what I have said, so you may want to wait for them ;)
 
F

Fushigi

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What am I missing about jumbo frame support? Basic GbE switches like the 8-port Netgear GS608 and it's 5-port cousin have it. Jumbo won't help when leaving the switch's environment, i.e. wireless & Internet, but should be fine for the LAN segment hosted on the switch itself.
 
ddrueding

ddrueding

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I was under the impression that a NIC either sends jumbo frames or it doesn't. If jumbo frames are enabled on the NIC, then everything it talks to has to be able to handle them. If your router can't handle jumbo frames, then that traffic won't get out. I believe this is why jumbo frames are either disabled by default or broken on many network devices. Switches that can handle jumbo frames simply pass them along, I was under the impression that you would need a bridge-like device to convert from jumbo to non-jumbo frames.

I would do the research, but I need to clean before guests arrive for dinner.
 
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Fushigi

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My impression was that jumbo frames are negotiated at each point in the link:
PC <--Jumbo--> Switch <--Regular--> Router and regular out of the router.
PC <--Jumbo--> Switch <--Jumbo--> Server
The switch would handle packet fragmentation & assembly when moving from Jumbo to Regular and back again. That's why the switches tend to have RAM; so they can manipulate the packets that need 'surgery' before sending them on.

Of course I could be wrong but that was my assumption.
 
P5-133XL

P5-133XL

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I don't think that is the way it works.

Switches do not manipulate or modify packets in any way: That takes a bridge or a router. Switches have RAM to keep keep track of and associate MAC addresses to individual ports, so it can quickly send an incoming packet to the correct port. They will also have ram, if they deal with multiple connection speeds so there will be a packet queue when sending from a fast connection (Gigabit), to a slower link (10/100).
 
Clocker

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So I'm a little confused. If I connect the two machines via a Gig-E switch that is behind a 10/100 router, will the traffic between the two machines that are local have to go through the 10/100 router and thus be slowed down to the speed of the router?

Thanks,
C
 
P5-133XL

P5-133XL

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Clocker said:
So I'm a little confused. If I connect the two machines via a Gig-E switch that is behind a 10/100 router, will the traffic between the two machines that are local have to go through the 10/100 router and thus be slowed down to the speed of the router?

Thanks,
C
Click to expand...
No, A connection between two Gigabit clients traveling through a 1000/100/10 router will travel at gigabit speeds, even if there is a 10/100 router on a different port. The purpose of the switche's queue is to deal with the situation when a gigabit client talks to a slower 100/10 Mbit client. It will then be accepting packets far faster than it can deliver them, so rather than having to throw them away, it will store some at least until the queue is filled up. If the connection is full-duplex, then the switch can also pause the gigabit client to allow the slower port to catchup.
 
Clocker

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Thanks Mark. Just to confirm...here my my setup:

Cable Modem-->Router (DHCP)-->GigE Switch-->Two PCs

The PCs are getting their IP addresses as well as their internet feed from the old router.

I'll be able to transfer data between the two PCs at full GigE speeds?

Thanks,
C
 
Clocker

Clocker

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And...I guess the other question is whether or not using Jumbo Frames for traffic that must go through my old router (i.e. to and fromt he internet) will cause some type of problem (i.e. data corruption or something) ??

Interesting info: http://sd.wareonearth.com/~phil/jumbo.html

How can jumbo frames and 1500 byte frames coexist?
Two basic approaches exist:

* On a port by port basis, where everything "downstream" from a given port is known to support jumbo frames.
* Using 802.1q Virtual LANs, where jumbo frame and non-jumbo frame devices are segregated to different VLANs.
Click to expand...

I don't have any idea how the 2nd approach works but it seems like the first approach is what I'm trying to do..?
 
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Stereodude

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I looked into all this before, and you're basically SOL for Jumbo frames.

You can do the VLAN thing with a switch that supports VLANs, and using 802.1q each of your gigabit NICs will end up looking like two NICs to Windows. In theory that would let you use Jumbo Frames between the two gigabit PCs on one virtual NIC, and not use jumbo frames between each gigabit PC and the router with the other virtual NIC.

The problem with this that I couldn't figure out to solve is how to force certain applications to use a particular virtual NIC.
 
ddrueding

ddrueding

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Computer 1 <----> Computer 2
192.168.0.100 <----> 192.168.0.105 - Without jumbo frames
10.0.0.100 <----> 10.0.0.105 - With jumbo frames


Now, if you refer to computer 2 using 10.0.0.105, it should use jumbo frames, no? If you keep your default gateway as 192.168.0.1, it should still go without for internet traffic.
 
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Stereodude

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Very interesting...

I think you would want to leave the dns and gateway entries empty on the jumbo frame "nic".
 
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Stereodude

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I might have to try this once I get a 24 port switch. Any suggestions for a 24 port 10/100/1000, VLAN supporting model? (noise not an issue) I've seen some reviewers rave about the Linksys SRW series of switches and all their capability for the price, but the reviews at Newegg are not kind to them.

Any opinions on the 3com 2924 Baseline Plus?

Apologies to Clocker for hijacking his thread.
 
J

Jan Kivar

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I have a D-Link DGS-1005D as switch, ZyXEL (Realtek chipset) and onboard NF3 NICs. I get ~25 MB/s, which is nice boost from the ~10 MB/s I got with the D-Link 10/100 switch/router/firewall/WLAN/whatever.

This is just the basic no jumbo frame Gig-E connection. The given speed is with FTP, I don't know whether Samba/CIFS or something else would have less overhead. Most likely the bottleneck is in the server, which is based on an Intel socket 370 board with 1,3 GHz Celeron.

I've also thought of getting a proper "managed" switch with VLAN support, but I can't justify paying ~160 euros for a 8-port HP 1800-8G to gain, what? 30 MB/s? 35 MB/s? 40 MB/s? I think 25 MB/s is borderline throughput for a single HDD with more than one process doing disk I/O simultaneously.

Furthermore, the size of the jumbo frame is mandated by the devices - not all devices support all jumbo frame sizes. That though isn't a large issue when dealing with VLANs, just leave the offending device(s) on the regular MTU, or buy better gear...

I can only hope that Stereodude's findings on the spin-off thread don't make me want to change my mind... :)

Cheers,

Jan
 
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