My operating system is Ubuntu 12.04. My cable modem is a motorola surfboard extreme. My comcast cable is 58 mbps. I'm using a belkin router. And my NIC is a NVIDIA Corporation MCP51 Ethernet Controller (rev a3).
The problem I have is I only get 100 mb/s speed:
$ sudo ethtool eth0
[sudo] password for myuser:
Settings for eth0:
Supported ports: [ MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Supported pause frame use: No
Supports auto-negotiation: Yes
Advertised link modes: 100baseT/Full
Advertised pause frame use: No
Advertised auto-negotiation: Yes
Speed: 100Mb/s
Duplex: Full
Port: MII
PHYAD: 1
Transceiver: external
Auto-negotiation: on
Supports Wake-on: g
Wake-on: d
Link detected: yes
When I try to switch speed to 1000, I lose network connection instantly:
$ sudo ethtool -s eth0 speed 1000 duplex full
$ sudo ethtool eth0
Settings for eth0:
Supported ports: [ MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Supported pause frame use: No
Supports auto-negotiation: Yes
Advertised link modes: 1000baseT/Full
Advertised pause frame use: No
Advertised auto-negotiation: Yes
Speed: Unknown!
Duplex: Unknown! (255)
Port: MII
PHYAD: 1
Transceiver: external
Auto-negotiation: on
Supports Wake-on: g
Wake-on: d
Link detected: no
I am forced to change it back to 100 to get network connection back. What is causing this issue?