Ethernet Problems: Link but no data

[julianoforti]

Folks,

I’m doing an ADSL test in Brazil with SMARTBITS (SMB) and Speed Touch Pro from Alcatel and DSLink from Ericsson.

- When I connect the SMB directly to the modem from Alcatel, the modem does not transmit any packet to the DSLAM but the Ethernet interfaces are up.
- I connected a hub between modem and SMB and the modem sent all packets to the DSLAM.
- When I connect the SMB directly to the modem from Ericsson, the modem WORKS VERY WELL without HUB.
- I connected my laptop to the SMB and the ethernet interface didn't go up.
- I connected another laptop to the SMB and the ethernet interface UP.

What kind of problem I can have?
Cable? If the problem is cable, why it works for some equipments? IS there any logical explanation to that?

Thanks for your help.

Juliano

 

[bcastner]

You have an autonegotiation issue with some of your adapters. The fault can lie in the autonegotiation logic of either the adapter, or the device, or both.

Check the Media Type/Speed/Duplex settings on the adapters to make sure that they are set to autosense.

If they are, the use of the switch/hub is perfectly reasonable to resolve the issue.

 

[julianoforti]

I configured my laptop and SMB to 10Mbps/Half and it didn't work.

This diagram worked a few weeks ago with the modems and now it stopped to work. The auto-negotiation can work sporadic or the problem is the cable, such as sensitive interface,....

 

[Crusher400]

I agree with bcastner. It seems to be a duplex/speed mis match from your equipment to your laptop. Remember that laptops, even same model can have different NIC cards and therefore one worked with auto and one did not. Auto-negotiation is not reliable.

You will need to read the manual for the equipment your using to find out what settings are supported. You may find out that certain equipment may not support the full range of 10/half, 10/full, 100/half & 100/full.

After you find out the common modes that all the connected equipment can support, set them to the best setting manually vs using auto-negotiate.