Help whith network device model

[jmperrote]

We are using VirtIO (paravirtualized) on all Vm's as network device model, because admin guide say that is " aim for maximum performance".

But we are detecting that on the os vms installed (ubuntu) the nic is --> configuration: autonegotiation=off, Auto-negotiation: off (command used lshw or ethtool) , but if we use Intel E1000 the nic is --> configuration: autonegotiation=on.

Why happens this, is correct ?

~# ethtool eth0
Settings for eth0:
Supported ports: [ ]
Supported link modes: Not reported
Supported pause frame use: No
Supports auto-negotiation: No
Supported FEC modes: Not reported
Advertised link modes: Not reported
Advertised pause frame use: No
Advertised auto-negotiation: No
Advertised FEC modes: Not reported
Speed: Unknown!
Duplex: Unknown! (255)
Port: Other
PHYAD: 0
Transceiver: internal
Auto-negotiation: off
Link detected: yes

**********

~# lshw -class network
*-network
description: Ethernet controller
product: Virtio network device
vendor: Red Hat, Inc.
physical id: 12
bus info: pci@0000:00:12.0
logical name: /dev/fb0
version: 00
width: 64 bits
clock: 33MHz
capabilities: msix bus_master cap_list rom fb
configuration: depth=32 driver=virtio-pci latency=0 mode=1024x768 visual=truecolor xres=1024 yres=768
resources: iomemory:10-f irq:10 ioport:1000(size=32) memory:40040000-40040fff memory:100000000-100003fff memory:40000000-4003ffff
*-virtio2
description: Ethernet interface
physical id: 0
bus info: virtio@2
logical name: eth0
serial: f6:cb:5b:09:b2:62
capabilities: ethernet physical
configuration: autonegotiation=off broadcast=yes driver=virtio_net driverversion=1.0.0 ip=10.11.37.186 link=yes multicast=yes


regards.

 

[Stefan_R]

The e1000 NIC emulates a regular ethernet "cable", so it tells the OS that it supports autoconfiguration. The paravirtualized virtio-net driver presents itself as a virtual interface directly, so the guest knows there is no cable, and thus there's no need for auto-configuration. virtio-net always operates at the maximum available speed.

Does this help, or is there actually something not working?