root@ubuntuZen:/home/mihai# ip a s
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master xenbr0 state UP group default qlen 1000
    link/ether 08:00:27:5d:d9:fb brd ff:ff:ff:ff:ff:ff
3: xenbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default
    link/ether 08:00:27:5d:d9:fb brd ff:ff:ff:ff:ff:ff
    inet 10.0.2.15/24 brd 10.0.2.255 scope global xenbr0
       valid_lft forever preferred_lft forever
    inet6 fe80::a00:27ff:fe5d:d9fb/64 scope link
       valid_lft forever preferred_lft forever
5: vif5.0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master xenbr0 state UP group default qlen 1
    link/ether fe:ff:ff:ff:ff:ff brd ff:ff:ff:ff:ff:ff
    inet6 fe80::fcff:ffff:feff:ffff/64 scope link
       valid_lft forever preferred_lft forever

___________________________


root@ubuntuZen:/home/mihai# brctl show
bridge name	bridge id		STP enabled	interfaces
xenbr0		8000.0800275dd9fb	no		eth0
							vif5.0
____________________________

root@ubuntuZen:/home/mihai# brctl showstp xenbr0
xenbr0
 bridge id		8000.0800275dd9fb
 designated root	8000.0800275dd9fb
 root port		   0			path cost		   0
 max age		  20.00			bridge max age		  20.00
 hello time		   2.00			bridge hello time	   2.00
 forward delay		  15.00			bridge forward delay	  15.00
 ageing time		 300.00
 hello timer		   1.24			tcn timer		   0.00
 topology change timer	   0.00			gc timer		  11.57
 flags


eth0 (1)
 port id		8001			state		     forwarding
 designated root	8000.0800275dd9fb	path cost		   4
 designated bridge	8000.0800275dd9fb	message age timer	   0.00
 designated port	8001			forward delay timer	   0.00
 designated cost	   0			hold timer		   0.22
 flags

vif5.0 (2)
 port id		8002			state		     forwarding
 designated root	8000.0800275dd9fb	path cost		 100
 designated bridge	8000.0800275dd9fb	message age timer	   0.00
 designated port	8002			forward delay timer	   0.00
 designated cost	   0			hold timer		   0.22
 flags