Aqui está a saída de uma das minhas máquinas Linux de bridge:
Com brctl showstp , você pode imprimir a lista de interfaces e seus parâmetros de spanning tree envolvidos na ponte. Lá, entre parênteses, você encontrará o índice de interface das interfaces constituintes - isso é o que é referenciado em brctl showmacs .
# brctl show
bridge name bridge id STP enabled interfaces
br0 3000.0a32fb000000 yes tap0
tap1
tap14
tap3
tap4
tap5
tap8
tap9
# brctl showstp br0
br0
bridge id 3000.0a32fb000000
designated root 3000.0a32fb000000
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 0.06 tcn timer 0.00
topology change timer 0.00 gc timer 139.36
flags
tap0 (1)
port id 8001 state forwarding
designated root 3000.0a32fb000000 path cost 100
designated bridge 3000.0a32fb000000 message age timer 0.00
designated port 8001 forward delay timer 0.00
designated cost 0 hold timer 0.00
flags
tap1 (2)
port id 8002 state forwarding
designated root 3000.0a32fb000000 path cost 100
designated bridge 3000.0a32fb000000 message age timer 0.00
designated port 8002 forward delay timer 0.00
designated cost 0 hold timer 0.00
flags
tap14 (12)
port id 800c state forwarding
designated root 3000.0a32fb000000 path cost 100
designated bridge 3000.0a32fb000000 message age timer 0.00
designated port 800c forward delay timer 0.00
designated cost 0 hold timer 0.00
flags
tap3 (3)
port id 8003 state forwarding
designated root 3000.0a32fb000000 path cost 100
designated bridge 3000.0a32fb000000 message age timer 0.00
designated port 8003 forward delay timer 0.00
designated cost 0 hold timer 0.00
flags
tap4 (4)
port id 8004 state forwarding
designated root 3000.0a32fb000000 path cost 100
designated bridge 3000.0a32fb000000 message age timer 0.00
designated port 8004 forward delay timer 0.00
designated cost 0 hold timer 0.00
flags
tap5 (5)
port id 8005 state forwarding
designated root 3000.0a32fb000000 path cost 100
designated bridge 3000.0a32fb000000 message age timer 0.00
designated port 8005 forward delay timer 0.00
designated cost 0 hold timer 0.00
flags
tap8 (6)
port id 8006 state forwarding
designated root 3000.0a32fb000000 path cost 100
designated bridge 3000.0a32fb000000 message age timer 0.00
designated port 8006 forward delay timer 0.00
designated cost 0 hold timer 0.00
flags
tap9 (8)
port id 8008 state forwarding
designated root 3000.0a32fb000000 path cost 100
designated bridge 3000.0a32fb000000 message age timer 0.00
designated port 8008 forward delay timer 0.00
designated cost 0 hold timer 0.00
flags
# brctl showmacs br0
port no mac addr is local? ageing timer
8 00:00:00:16:d7:28 yes 0.00
12 00:00:00:23:4c:3b yes 0.00
1 00:00:00:24:fb:74 yes 0.00
8 00:00:00:54:20:b5 no 44.91
2 00:00:00:5b:14:3d yes 0.00
6 00:00:00:6b:dc:8c no 45.22
4 00:00:00:81:6d:8d no 45.03
1 00:00:00:81:6d:92 no 45.00
2 00:00:00:a2:4f:16 no 7.24
8 00:00:00:a2:4f:7e no 53.66
2 00:00:00:a2:4f:9e no 25.54
2 00:00:00:b1:8a:35 no 44.86
3 00:00:00:b8:14:87 yes 0.00
5 00:00:00:c2:7b:d2 no 16.28
12 00:00:00:d4:6c:ea no 45.02
4 00:00:00:ee:25:9f yes 0.00
5 00:00:00:ef:01:b2 no 0.57
Você pode perguntar por que a numeração do índice da interface não é consecutiva. Bem, originalmente, quando você inicia sua ponte e adiciona interfaces a ela, é. Então, se você remover uma interface, as interfaces deixadas na bridge não terão seus números reordenados. No entanto, esses buracos são preenchidos quando você começa novamente a adicionar interfaces à ponte.