s305 – network infrastructure chapter 6 local area network
TRANSCRIPT
S305 – Network Infrastructure
Chapter 6
Local Area Network
Announcements and OutlineSubnetting ReviewCIDR NotationNumber of SubnetsNumber of Hosts
OutlineLAN/WLAN ComponentsTraditional Ethernet (IEEE 802.3)Switched EthernetWireless LANBest Practices Improving Performance
2Copyright 2010 John Wiley & Sons, Inc
Why Use a LAN?
Information sharing
Resource sharing
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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
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Basic LAN/WLAN Components
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Component - Network Interface Cards (NICs)
Also called network cards and network adapters
Mostly built into motherboards today
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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
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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
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1.
Ethernet Media Types
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Planning for LAN Installations
Critically important with today’s LAN explosions
Cheapest point to install the cable?
Wiring Closets
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Wiring Closets
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Wiring Closets
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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
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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:•
•
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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?
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Forwarding Tables
What happens when a frame is received?
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Performance Comparison – Hub vs. Switch
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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
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CSMA/CD
Carrier Sense (CS):
Multiple Access (MA):
Collision Detect (CD):
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Best Practice Recommendations - LAN
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Improving LAN Performance
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Identifying Network Bottlenecks
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Improving Network Server Performance
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Improving Network Circuit Capacity
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Network Segmentation
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Reducing Network Demand