1. Networks: Bridges1 Bridges

2. Networks: Bridges2 Repeater S1S2 S3 LAN1LAN2 S4 A repeater operates at the physical layer and forwards everything between the two LANs. LAN1 and LAN2 are in the same collision domain.

3. Networks: Bridges3 Figure 6.79Copyright ©2000 The McGraw Hill Companies Leon-Garcia & Widjaja: Communication Networks

4. Networks: Bridges4 Bridges Operate at the data link layer. Bridges 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 the location of the destination node. Bridge management gets more complicated when loops are possible in the frame route.

5. Networks: Bridges5 Bridge Network Physical Network LLC Physical LLC MAC Figure 6.80 Bridge A bridge is a store and forward device that separates collision domains. Copyright ©2000 The McGraw Hill CompaniesLeon-Garcia & Widjaja: Communication Networks

6. Networks: Bridges6 B1 S1S2 B2 S3S4 S5 Address Port port 1port 2port 1port 2 LAN1LAN2LAN3 Figure 6.81 Copyright ©2000 The McGraw Hill CompaniesLeon-Garcia & Widjaja: Communication Networks

7. Networks: Bridges7 B1 S1S2 B2 S3S4 S5 Address Port port 1port 2port 1port 2 LAN1LAN2LAN3 S1 S5 S11 1 Figure 6.82 Copyright ©2000 The McGraw Hill CompaniesLeon-Garcia & Widjaja: Communication Networks

8. Networks: Bridges8 B1 S1S2 B2 S3S4 S5 Address Port port 1port 2port 1port 2 LAN1LAN2LAN3 S3 S2 S11 1 S32 1 Figure 6.83Copyright ©2000 The McGraw Hill CompaniesLeon-Garcia & Widjaja: Communication Networks

9. Networks: Bridges9 B1 S1S2 B2 S3S4 S5 Address Port port 1port 2port 1port 2 LAN1LAN2LAN3 S4 S3 S11 1 S32 1 S42 2 Figure 6.84Copyright ©2000 The McGraw Hill CompaniesLeon-Garcia & Widjaja: Communication Networks

10. Networks: Bridges10 Bridge1 S1S2 Bridge 2 S3S4 S5 Address Port port 1port 2port 1port 2 LAN1LAN2LAN3 S2 S1 S11 1 S32 1 S42 2 S21 Figure 6.85Copyright ©2000 The McGraw Hill Companies Leon-Garcia & Widjaja: Communication Networks

11. Networks: Bridges11 (1) (2) (3) Figure 6.86Copyright ©2000 The McGraw Hill Companies Leon-Garcia & Widjaja: Communication Networks MANs with Bridge Loops

12. Networks: Bridges12 Figure 6.87 Copyright ©2000 The McGraw Hill Companies Leon-Garcia & Widjaja: Communication Networks MANs with Bridge Loops Solution to bridge loops Build a Spanning Tree!