1. S305 – Network Infrastructure Chapter 6 Local Area Network

2. Announcements and Outline Subnetting Review CIDR Notation Number of Subnets Number of Hosts Outline LAN/WLAN Components Traditional Ethernet (IEEE 802.3) Switched Ethernet Wireless LAN Best Practices Improving Performance 2 Copyright 2010 John Wiley & Sons, Inc

3. Why Use a LAN? Information sharing Resource sharing 3

4. Network Types Dedicated server network Permanently assigned a specific task May form a powerful enterprise network replacing mainframes Runs a server network operating system (NOS) (Windows 2008) Common Servers: web, email, print Peer-to-peer network Having hardware devices shared by all users (printers, internet) All computers act as both clients and servers Results in reduced costs 4

5. Basic LAN/WLAN Components 5

6. Component - Network Interface Cards (NICs) Also called network cards and network adapters Mostly built into motherboards today 6

7. Component - Hubs & Switches Act as junction boxes, linking cables from several computers on a network May allow connection of more than one kind of cabling, such as UTP and coax. Repeater (reconstruct and strengthen) incoming signals 7

8. Component - Network Cables Used to connect a computer physically to the network Types of cables  Unsheilded wire pairs (UTP) – leading LAN cable type  Shielded twisted pair (STP)  Optical fiber – high capacity, just beginning in LANs 8

9. 1. Ethernet Media Types 9

10. Planning for LAN Installations Critically important with today’s LAN explosions Cheapest point to install the cable?

11. Wiring Closets 11

12. Wiring Closets 12

13. Wiring Closets 13

14. Component – Software Software that controls the LAN Parts of Network Operating System  Server version of NOS Runs on the network servers  Client version of NOS Runs on the client computers  Network Profiles Indicate the resources available in the network and authorized users  Directory Service Provide information about resources on the LAN 14

15. Traditional Ethernet (IEEE 802.3) - Wired Used by almost all LANs today Originally developed by a consortium of Digital Equipment Corp., Intel and Xerox Standardized as IEEE 802.3 Types of Ethernet: 15

16. Switched Ethernet Uses workgroup switches Logical and physical topology of the network becomes a star topology via switch Switch reads destination address of the frame and only sends it to the corresponding port How does a hub handle frames? 16

17. Forwarding Tables What happens when a frame is received? 17

18. Performance Comparison – Hub vs. Switch 18

19. Media Access Control (MAC) Uses a contention-based protocol called CSMA/CD (Carrier Sense Multiple Access / Collision Detect) Frames can be sent by two computers on the same network at the same time 19

20. CSMA/CD Carrier Sense (CS):  Multiple Access (MA):  Collision Detect (CD):  20

21. Best Practice Recommendations - LAN 21

22. Improving LAN Performance 22

23. Identifying Network Bottlenecks 23

24. Improving Network Server Performance 24

25. Improving Network Circuit Capacity 25

26. Network Segmentation 26

27. Reducing Network Demand