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Semester 1Semester 1
CHAPTER 3CHAPTER 3
Le Chi TrungLe Chi Trung
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ContentContent
• Basic LAN devices
• Basics of data flow through LANs
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ScheduleSchedule
No Name Est time No Name30-Jul Chapter 2 Online Exam
3.1 Basics LAN devices 1:00:003.2 The evolution of network devices
01-Aug 3.3 The basics of data flow through LANs 0:30:00 Discussion3.4 The building of LANs 3.4.2 Basic LAN setup
Summary Chapter 3 0:30:0003-Aug Chapter 3 Online Exam
DateLesson Lab
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BASIC LAN DEVICESBASIC LAN DEVICES
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Are you able to describe this diagram?Are you able to describe this diagram?
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Physical & Logical TopologiesPhysical & Logical Topologies
• Physical topologies
– Define the actual layout of the wire (media)
• Logical topologies
– Define how the media is accessed by the hosts
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Physical TopologiesPhysical Topologies
Bus
Ring
Star
ExtendedStar
Hierarchical
Mesh
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Physical Topology:Physical Topology: Bus Bus
• Single backbone
• All hosts directly connected to backbone
• Each end of the bus must be properly terminated
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Physical Topology:Physical Topology: Ring Ring
• No backbone
• A host is directly connected to each of its neighbors
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Physical Topology:Physical Topology: Star Star
• All devices connected to a central point
• Center of star is usually a hub or a switch
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Physical Topology:Physical Topology: Extended Star Extended Star
• Connects individual star topologies together.
• At the center of the star is a hub or a switch.
• Extends the length and size of the network.
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Physical Topology:Physical Topology: Hierarchical Hierarchical
• Like the extended star except a computer controls traffic (not a hub or a switch).
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Physical Topology:Physical Topology: Mesh Mesh
• Each host has its own connection to every other host.
• Used in situations where communication must not be interrupted.
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Logical TopologiesLogical Topologies
Broadcast
Token Passing
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Logical Topology:Logical Topology: BroadcastBroadcast
• Each host on the LAN sends its data (or broadcasts its data) to every other host.
• First-come, first-serve.
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Logical Topology:Logical Topology: Token PassingToken Passing
• Access to media is controlled by an electronic token.
• Possession of the token gives the host the right to pass data to its destination.
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TechnologiesTechnologies
Ethernet
FDDI
Token Ring
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Technology:Technology: Token Ring Token Ring
Token Ring
Token Passing
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Technology:Technology: FDDI FDDI
FDDI
Token Passing
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Technology:Technology: Ethernet Ethernet
Ethernet
Broadcast
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HostsHosts
Computer Server
Printer
NICNIC
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LAN Media SymbolsLAN Media Symbols
TokenRing
FDDIRing
EthernetLine
SerialLine
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OSI Review:OSI Review: Layer 1 Layer 1
• Responsibility:– Transmission of an unstructured bit stream
over a physical link between end systems.
• Concerned:– Bits.
– Electrical specifications.
– Physical data rate.
– Distances.
– Physical connector.
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LAN Device:LAN Device: Transceiver Transceiver
• Connect different media technologies.
• Layer 1 device.
UTP
BNC
AUI
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LAN Device:LAN Device: Repeater Repeater
• Regenerates and repeats the signal.
• Layer 1 device.
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LAN Device:LAN Device: Hub Hub
• A multi-port repeater.
• Layer 1 device.
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OSI Review:OSI Review: Layer 2 Layer 2
• Responsibility:– Provides for the reliable transfer of data
cross a physical link.
• Concerned:– Frames.
– Physical address (HW or MAC): Flat.
– Line discipline.
– Error and flow control.
– “Segment”.
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LAN Device:LAN Device: NIC NIC
• Network interface of hosts.
• Build-in physical address.
• Layer 2 device.
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LAN Device:LAN Device: Bridge Bridge
• Keeps traffic local by filtering traffic based on physical addresses.
• Layer 2 device.
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LAN Device:LAN Device: Switch Switch
• A multi-port bridge.
• Layer 2 device.
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OSI Review:OSI Review: Layer 3 Layer 3
• Responsibility:– Connection and path selection between two
end system across networks.
• Concerned:– Packets.
– Logical address: Hierarchical.• Networks and Hosts addressing.
– Route , Routing table, Routing protocol.
– “Network”.
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LAN Device:LAN Device: Router Router
• Makes decisions based on network addresses (logical addresses).
• Layer 3 device.
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LAN Device:LAN Device: Router Functions Router Functions
• Path determination:
– The process of evaluating a packet’s destination IP address so that the router can decide which port to send out the packet.
• Packet switching:
– The router re-encapsulates the packet in the protocol needed for the specified port and then switches the packet out that port.
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LAN Device:LAN Device: Cloud Cloud
• Another network
• Include layer 1 – 7 devices
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Devices function at LayersDevices function at Layers
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Teaching TopologyTeaching Topology
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History of NetworkingHistory of Networking
Homework
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ReviewReview
• Physical and logical topologies.
• LAN devices.
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DATA FLOW THROUGH LANsDATA FLOW THROUGH LANs
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Air Mail ExampleAir Mail Example
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EncapsulationEncapsulation
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Encapsulation:Encapsulation: Example Example
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Host to host communicationHost to host communication
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Packet Flow: Packet Flow: Layer 1 DeviceLayer 1 Device
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Packet Flow: Packet Flow: Layer 2 DeviceLayer 2 Device
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Packet Flow:Packet Flow: Layer 3 Device Layer 3 Device
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Packet Flow:Packet Flow: Layer 1-7 Device Layer 1-7 Device
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Packet Traveling Over NetworkPacket Traveling Over Network
Homework
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Preparation for LABPreparation for LAB
• 3.4.1: Readiness.
• 3.4.2: Building a simple network.
• Lab companion:
– 3.4.2
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ReviewReview
• Encapsulation.
• Data flow.