Bridges

Figure 6.79

Bridges Operate at the data link layer Also use backward learning in recording source address on transmissions Unlike repeaters, bridges will not forward a frame onto another LAN segment if it knows about location of destination node Bridge management gets more complicated when loops are possible in the frame route.

Bridge Network Physical Network LLC Physical LLC MAC Figure 6.80

B1 S1S2 B2 S3S4 S5 Address Port port 1port 2port 1port 2 LAN1LAN2LAN3 Figure 6.81

B1 S1S2 B2 S3S4 S5 Address Port port 1port 2port 1port 2 LAN1LAN2LAN3 S1 S5 S11 1 Figure 6.82

B1 S1S2 B2 S3S4 S5 Address Port port 1port 2port 1port 2 LAN1LAN2LAN3 S3 S2 S11 1 S32 1 Figure 6.83

B1 S1S2 B2 S3S4 S5 Address Port port 1port 2port 1port 2 LAN1LAN2LAN3 S4 S3 S11 1 S32 1 S42 2 Figure 6.84

Bridge1 S1S2 Bridge 2 S3S4 S5 Address Port port 1port 2port 1port 2 LAN1LAN2LAN3 S2 S1 S11 1 S32 1 S42 2 S21 Figure 6.85

(1) (2) (3) Figure 6.86

Figure 6.87