1. Connecting LANs, Backbone Networks, and Virtual LANs 01204325: Data Communication and Computer Networks Asst. Prof. Chaiporn Jaikaeo, Ph.D. chaiporn.j@ku.ac.th http://www.cpe.ku.ac.th/~cpj Computer Engineering Department Kasetsart University, Bangkok, Thailand Adapted from lecture slides by Behrouz A. Forouzan © The McGraw-Hill Companies, Inc. All rights reserved

2. 2 Outline Network connecting devices Network connecting devices Backbone networks Backbone networks Virtual LANs Virtual LANs

3. 3 Network Connecting Devices

4. 4 Layer-1 Connecting Devices

5. 5 Repeaters Connected segments become single collision domain Connected segments become single collision domain

6. 6 Repeater Function

7. 7 Hubs Similar to multiport repeaters Similar to multiport repeaters All segments belong to the same collision domain All segments belong to the same collision domain

8. 8 Layer-2 Connecting Devices

9. 9 Bridges Bridges process information up to the frame-level (layer 2) Bridges process information up to the frame-level (layer 2)

10. 10 Bridges Connecting LANs while separating collision domains Connecting LANs while separating collision domains MAC addresses are used for filtering MAC addresses are used for filtering Connected segments form a single network (same broadcast domain) Connected segments form a single network (same broadcast domain)

11. 11 Learning Bridges A  D E  A B  C

12. 12 Loop Problem

13. 13 Graph Representation

14. 14 Creating Spanning Tree

15. 15 Blocking Ports

16. 16 Switches Similar to multiport bridges Similar to multiport bridges Also run Spanning-Tree Protocol Also run Spanning-Tree Protocol

17. 17 Layer-3 Connecting Devices

18. 18 Routers Capable of connecting networks of different types Capable of connecting networks of different types Routers separate networks into different broadcast domains Routers separate networks into different broadcast domains

19. Backbone Networks

20. 20 Bus Backbone

21. 21 Star Backbone

22. 22 Connecting Remote LANs

23. Virtual LANs

24. 24 Regular Switch Three LANs are connected by a regular switch, forming one LAN (one broadcast domain) Three LANs are connected by a regular switch, forming one LAN (one broadcast domain)

25. 25 Switch with VLAN Feature Different VLANs belong to different broadcast domains Different VLANs belong to different broadcast domains They are considered isolated networks They are considered isolated networks

26. 26 Multiple VLAN Switches Trunk

27. 27 Routing Across VLANs Router is required to connect different VLANs Router is required to connect different VLANs Trunk