2 Local Machines Via Switch + Router for Net

mothermachine

mothermachine

mothermachine

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8 Oct 2004
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Hi folks,

Here is my scenario:

I have 2 PCs with Gigabit network adapters each connected to a Gigabit switch. Also connected to this same switch is a BTHomeHub of a colleage, which is providing the Internet connection to the first switch (and therefore my 2 PCs). Also on his BTHub is a couple of his own rubbish PCs which are running at 100mbs.

I think the issue is that his PCs are running at 100mb/s which is pulling the entire network down to 100mb/s including my own switch and PCs.

Question: Is there a way to maintain my 2 PCs at Gigabit speed while still using his BTHub/PCs at 100mb/s?

Thanks!
 
I think I found a Gigabit port on his HomeHub. So in theory if I connect my Switch to his hub in this port, it should maintain Gigabit speed along the network back to my switch + my 2 PCs... I think....
 
Speed, I would have thought, should be negotiated seperately on each port ... so at worst the link from router to switch would be 100Mb with the each PC still connecting to the switch at 1Gb ... clearly the path to the router will be limiting speed from PC to router but then again from their out to internet you're going to be less than 100Mb on a BT connection!
 
deshepherd said:
Speed, I would have thought, should be negotiated seperately on each port ... so at worst the link from router to switch would be 100Mb with the each PC still connecting to the switch at 1Gb ... clearly the path to the router will be limiting speed from PC to router but then again from their out to internet you're going to be less than 100Mb on a BT connection!
Click to expand...

My understanding is that if you have even one device running at 100mb/s it will pull the whole network down to 100mb/s. But I'm hoping I'm wrong, or that the special Gigabit port on the HomeHub will stop that happening.

All the adapters on my machines are set to Auto Negotiate. I could try forcing them to Gigabit and see what happens but I don't think that should be necessary. If they could run at Gigabit with the current config then they should be already.
 
Copying a file between your 2 PC's on the gigabit switch should result in upto gigabit speeds (overall speed is very dependent on what your transferring, how big it is, what switch you are using and network adapters on the PC's).

If you copy a file from your PC to his or vice versa then the most you can hope for is up to 100mb/s as the home hub and his slower NIC's will slow the connection down. Likewise with the internet, that will still be constrained to a 100mb/s LAN connection from the home hub unless using the gigabit socket (assuming this is the home hub 3?)

The fact his PC's are only running 100mb/s shouldn't slow the entire network down to 100mb/s. The only time I'm aware anything like this will happen is with wireless N. if using a single band 2.4ghz wireless N router and one device connects at 54g, it slows the wireless down for all devices to 54g regardless. This is where dual band wireless N comes into play. In the case of the wireless it doesn't affect the speed of the wired network as such (still can be connected at gigabit speeds but copying a file from pc to laptop on 54g will obviously limit transfer speeds to 54g). Assuming you don't share data/connect to his PC's then connecting your switch to the single gigabit port on the home hub won't actually do anything bar provide a gigabit link for the internet.

You could try and enable jumbo frames on your PC's NIC's and see if that helps with transfer speeds.
 
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cokecan said:
Copying a file between your 2 PC's on the gigabit switch should result in upto gigabit speeds (overall speed is very dependent on what your transferring, how big it is, what switch you are using and network adapters on the PC's).

If you copy a file from your PC to his or vice versa then the most you can hope for is up to 100mb/s as the home hub and his slower NIC's will slow the connection down. Likewise with the internet, that will still be constrained to a 100mb/s LAN connection from the home hub unless using the gigabit socket (assuming this is the home hub 3?)

The fact his PC's are only running 100mb/s shouldn't slow the entire network down to 100mb/s (The only time I'm aware this will happen is with wireless N. if using a single band 2.4ghz wireless N router and one device connects at 54g, it slows the wireless down for all devices to 54g regardless. This is where dual band wireless N comes into play). Assuming you don't share data/connect to his PC's then connecting your switch to the single gigabit port on the home hub won't actually do anything bar provide a gigabit link for the internet.

You could try and enable jumbo frames on your PC's NIC's and see if that helps with transfer speeds.
Click to expand...

But I assume this is only the case if the Network Adapters are actually operating at Gigabit speed, and they're not (they're on Auto and syncing at 100mb/s). So what I need to do then is force them to use Gigabit and see if that works. In the past, I've seen that this only works if ALL machines on the same network at running Gigabit, otherwise they will all drop to 100mb/s.

The internet speed itself is totally irrelevant as you say. But the point is that I think it's the other machines connected to the Router at 100mb/s that are pulling my end of the network down to 100mb/s as well.

I can't test that port out until tomorrow unfortunately but I'll try forcing my adapters to Gigabit and see what happens.

Cheers,
 
deshepherd is correct. The 100 Mbit machines shouldn't be forcing the Gigabit capable machines to connect at a lower speed.

It's easy enough to prove. Just try the two Gigabit machines on their own and see what they sync at.
 
Ok I just tried to force one of my PCs to run at Gigabit in the adapter config and it wouldn't establish a connection (link) to the Switch or end Router at all. Dropping it back down to Auto Negotiate drops it to 100mb/s and it works fine.

I will now test by removing the HomeHub from the Switch and therefore ONLY gigabit machines on the network, and see if I can move up to Gigabit.
 
Unplug the switch from the router so just the two PCs are connected to the switch, do they show as 100mb/s then.

If yes, the router has no bearing on it, if they show as 1000mb/s then the router is somehow causing it, odd one as I have never had this and I have 2 routers and two switches in my home setup only one of which is gigabit and all the devices connected to the gigabit switch are running at 1000mb/s.
 
as above, check network cables and also remember if you are only connecting to the switch without the router you will need to assign an IP to each PC as the router's DHCP wont be able to assign one
 
pepp77 said:
Unplug the switch from the router so just the two PCs are connected to the switch, do they show as 100mb/s then.

If yes, the router has no bearing on it, if they show as 1000mb/s then the router is somehow causing it, odd one as I have never had this and I have 2 routers and two switches in my home setup only one of which is gigabit and all the devices connected to the gigabit switch are running at 1000mb/s.
Click to expand...

And we have a solution! For some reason I completely forgot to replace a temporary network cable with a proper one (it was a horrible cheapo crossover cable I borrowed from a mate) - replaced it with a decent CAT5E and boom - Gigabit speed.

Thanks folks! Sometimes talking through a problem really works even if the solution is stupidly simple...
 
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