S305 – Network Infrastructure Chapter 6 Local Area Network

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

Why Use a LAN? Information sharing Resource sharing 3

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, , 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

Basic LAN/WLAN Components 5

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

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

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

1. Ethernet Media Types 9

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

Wiring Closets 11

Wiring Closets 12

Wiring Closets 13

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

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 Types of Ethernet: 15

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

Forwarding Tables What happens when a frame is received? 17

Performance Comparison – Hub vs. Switch 18

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

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

Best Practice Recommendations - LAN 21

Improving LAN Performance 22

Identifying Network Bottlenecks 23

Improving Network Server Performance 24

Improving Network Circuit Capacity 25

Network Segmentation 26

Reducing Network Demand