Friday, May 22, 2009

What is a virtual bridge Virbr0 ?

A virtual bridge, can be defined as a device that
bridges virtual interfaces. It provides an easy
means of networking virtual networking devices
such as venet (virtual network) or veth (virtual
ethernet).

Typically, a virtual bridge Virbr0, has point to
point devices such as venet devices. So whenever
traffic is directed from the kernel to one of the
guest VMs / virtual containers, if the vbridge
is configured with the right IP address and subnet
information, it accepts traffic from the kernel.
Internally, the bridge then forwards the packet to
the correct venet interface as it learns their IPs.
So the typical configuration is -

virbr0 ----------> venet0 -----> eth0 192.168.10.2
|
----- > venet 1 -----> eth0 192.168.10.5

In this case virbr0 could have an IP of 192.168.10.7/24.
Hence virbr0 takes all traffic for 192.168.10.0 and
sends it to the venets which are typically point-point
devices.

If you have any questions please post a comment.

1 comments:

Sethu said...

Hey can you explain more about this. When i create a VM , I dont get to see the IP address. While loading the OS , It says determining IP failed ..... My mail id is sethusubbiah@gmail.com. Please help me out if u can. Thanks !

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