Poor transfer speeds with Dlink Gigabit switch

Rickster said:
I know im right, I just need proof.
Click to expand...
So you think because 1 unrelated device attached to it is at 100Mbs every device attached will max out at 100Mbs even if they're Gbit?

Please go buy a switch and try this.
 
calypso said:
Maybe it's just a dud switch? I got 8 of them in the office. One had poor speeds, swopped it out and now all is good.
Click to expand...

Hmm. I bought 2 switches. The other one is still in the box. Perhaps I should try that. I never had a switch fail on me like that...Even them fong kong chinese ones..
 
janplank said:
Hmm. I bought 2 switches. The other one is still in the box. Perhaps I should try that. I never had a switch fail on me like that...Even them fong kong chinese ones..
Click to expand...

That's exactly what I thought. I imagined either it works or its dead. But after the second user complained about speeds I knew something was up.
 
slvr said:
So you think because 1 unrelated device attached to it is at 100Mbs every device attached will max out at 100Mbs even if they're Gbit?

Please go buy a switch and try this.
Click to expand...

Aaah...not so fast. If the 100Mbps device is pulling the full 100Mbps then he is partially right. You will run into a situation with cheaper switches which don't have big enough buffers, the 100Mbps device will send pause frames and slow all the gigabit connections down to 100Mbps...head of line blocking.

EDIT: This only applies when the 100Mbps device is saturating the link and only seems to happen on cheaper switches with small buffers.

So you both right depending on the switch fabric :-)
 
Last edited:
eddief1 said:
Aaah...not so fast. If the 100Mbps device is pulling the full 100Mbps then he is partially right. You will run into a situation with cheaper switches which don't have big enough buffers, the 100Mbps device will send pause frames and slow all the gigabit connections down to 100Mbps...head of line blocking.
Click to expand...

While that may be true, that was not the original assertion:

You cant have some devices running gigabit and some fast Ethernet, if one device is 100meg then all other devices will be transferring at 100meg.
Click to expand...

No mention was made of the 100Mbps device running at full tilt at the same time.

And yes, it is easy to come up with scenarios where the performance of a switch with mixed devices may deteriorate. But this is not what was claimed. Even in your example, so long as the 100Mbps device is not involved in any communications with the two Gbps devices, the switch should still be able to achieve near gigabit speeds, assuming the switch is able to sustain the required packet rate of both streams.
 
RoganDawes said:
No mention was made of the 100Mbps device running at full tilt at the same time.
Click to expand...

Fair enough, but logic would say he run tests which would have saturated the link, how else would he have tested his theory?

Even in your example, so long as the 100Mbps device is not involved in any communications with the two GBE devices, the switch should still be able to achieve near gigabit speeds, assuming the switch is able to sustain the required packet rate of both streams.
Click to expand...

This is true of course, two gigabit devices communicating directly with each other would be unaffected, but a 100Mbps device and a gig device both communicating with say a gig file server...this is probably how he ran his tests hence his conclusion.

You cant have some devices running gigabit and some fast Ethernet, if one device is 100meg then all other devices will be transferring at 100meg.
Click to expand...

Anyway...the point is everyone jumped on him for saying that having a single 100Mbps device can affect gig devices, when in fact it can.
 
Last edited:
eddief1 said:
Fair enough, but logic would say he run tests which would have saturated the link, how else would he have tested his theory?



This is true of course, two gigabit devices communicating directly with each other would be unaffected, but a 100Mbps device and a gig device both communicating with say a gig file server...this is probably how he ran his tests hence his conclusion.
Click to expand...

But he said:

I bought a TPlink gigabit NIC for the NAS
Click to expand...
 
Just to clear it up, I did not as yet test speeds with the gigabit nic after the poor performance of the switch.

Are you saying that if I copy a 10gb file from one PC to another via gigabit switch and NIC's and one PC is connected via the gigabit switch to a 100Mbit router that's on the web, the actual act of browsing the web would cause the gigabit port to throttle back to 100Mbits???
 
janplank said:
Just to clear it up, I did not as yet test speeds with the gigabit nic after the poor performance of the switch.

Are you saying that if I copy a 10gb file from one PC to another via gigabit switch and NIC's and one PC is connected via the gigabit switch to a 100Mbit router that's on the web, the actual act of browsing the web would cause the gigabit port to throttle back to 100Mbits???
Click to expand...

No, you should get gigabit speeds on the file copy barring hardware limitations (PCI bus, HDD Speeds)
 
Rickster said:
You cant have some devices running gigabit and some fast Ethernet, if one device is 100meg then all other devices will be transferring at 100meg.

Also set all switches and PC's to auto negotiation.
Click to expand...
Er, no.
 
You must log in or register to reply here.
Back
Top
Sign up to the MyBroadband newsletter
X