Ethernet

Resources

This article describes the setup of an Ethernet network device.

Installation

Hardware detection

To choose the right driver, first detect the used Ethernet controllers. Use lspci for this task:

root #lspci | grep --color Ethernet

Kernel

The next step is to activate the kernel options appropriate to the Ethernet hardware in the machine. Open up a second terminal window in order to reference the output generated in the step above. The option to enable Ethernet drivers can be found in the following location:

KERNEL

Device Drivers  --->
    Networking support  --->
        [*] Network device support --->
            [*]   Ethernet driver support  --->

Scan the drivers carefully. Compare the results of the lspci command above with the available drivers in the list. Enable the feature(s) that match the installed Ethernet device(s).

Note
For more information on configuring the kernel see the kernel configuration article.

Configuration

Physical interface settings

List eth0 physical interface settings using sys-apps/ethtool:

root #ethtool eth0

Settings for eth0:
        Supported ports: [ TP ]
        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:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Advertised pause frame use: No
        Advertised auto-negotiation: Yes
        Speed: 1000Mb/s
        Duplex: Full
        Port: Twisted Pair
        PHYAD: 0
        Transceiver: internal
        Auto-negotiation: on
        MDI-X: off (auto)
        Supports Wake-on: umbg
        Wake-on: g
        Current message level: 0x00000007 (7)
                               drv probe link
        Link detected: yes

Or using mii-tool from sys-apps/net-tools package:

root #mii-tool eth0 -v

eth0: negotiated 1000baseT-FD flow-control, link ok
  product info: vendor 23:58:00, model 42 rev 0
  basic mode:   autonegotiation enabled
  basic status: autonegotiation complete, link ok
  capabilities: 1000baseT-FD 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD
  advertising:  1000baseT-FD 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD flow-control
  link partner: 1000baseT-HD 1000baseT-FD 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD

Note
The output of mii-tool sometimes does not work for certain network drivers.

Physical interface features (TCP offloading)

Sometimes NIC's have basic/partial TCP/IP stack implementation, and support offloading of certain networking routines/protocols to the NIC chip.

Example below shows network interface offloading features supported on device eth0:

root #ethtool --show-offload eth0

Features for eth0:
rx-checksumming: off
tx-checksumming: on
        tx-checksum-ipv4: off [fixed]
        tx-checksum-ip-generic: on
        tx-checksum-ipv6: off [fixed]
        tx-checksum-fcoe-crc: off [fixed]
        tx-checksum-sctp: off [fixed]
scatter-gather: on
        tx-scatter-gather: on
        tx-scatter-gather-fraglist: off [fixed]
tcp-segmentation-offload: on
        tx-tcp-segmentation: on
        tx-tcp-ecn-segmentation: off [fixed]
        tx-tcp6-segmentation: off [fixed]
udp-fragmentation-offload: off [fixed]
generic-segmentation-offload: on
generic-receive-offload: on
large-receive-offload: off [fixed]
rx-vlan-offload: on
tx-vlan-offload: on [fixed]
ntuple-filters: off [fixed]
receive-hashing: off [fixed]
highdma: off [fixed]
rx-vlan-filter: on [fixed]
vlan-challenged: off [fixed]
tx-lockless: off [fixed]
netns-local: off [fixed]
tx-gso-robust: off [fixed]
tx-fcoe-segmentation: off [fixed]
fcoe-mtu: off [fixed]
tx-nocache-copy: on
loopback: off [fixed]
rx-fcs: off
rx-all: off

External resources

TCP offload engine (Wikipedia)
Ethernet (Arch Wiki)