CSA Week 9

Overview

We will briefly cover:Layered architectureNetwork addressing

CSA Week 9

Layered Architecture - Protocols

ProtocolsThe format or structure of the messageThe method by which networking devices share

information about pathways with other networksHow and when error and system messages are

passed between devicesThe setup and termination of data transfer

sessions

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Layered Architecture

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Layered Architecture

Web server and Web browser interactionHttpTCPIPEthernet

Layered architecture is used to visualize interaction of many different protocols

CSA Week 9

Layered Architecture

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Layered Architecture- OSI Model

CSA Week 9

Layered Architecture Help in design of complex, multiuse, multi-vendors networks

Assists in protocol design, because protocols that operate at a specific layer have defined information that they act upon and a defined interface to the layers above and below

Fosters competition because products from different vendors can work together

Prevents technology or capability changes in one layer from affecting other layers above and below

Provides a common language to describe networking functions and capabilities

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Layered Architecture- OSI Model

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OSI Model Data Encapsulation

Segment

Packet

Frame

Bits

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Layered Architecture- OSI Model Application Layer

provides the interface to the user and the rules for communication between applications the Application layer protocols implemented on the source and destination host must match

Presentation Coding and conversion of Application layer data to ensure that data from the source device can be

interpreted by the appropriate application on the destination device. Compression of the data in a manner that can be decompressed by the destination device Encryption of the data for transmission and the decryption of data upon receipt by the destination

Session create and maintain dialogs between source and destination applications

Transport Enables multiple applications to communicate over the network at the same time on a single device -

port numbers Ensures that, if required, all the data is received reliably and in order by the correct application Employs error handling mechanisms TCP, UDP

CSA Week 9

Layered Architecture- OSI Model

Network Enables devices to reach each other

Logical addressing Routing IPv4, IPv6, Novell IPX, AppleTalk

Data Link To prepare Network layer packets for transmission and to control access to the physical media Controls how data is placed onto the media and is received from the media using techniques

such as media access control and error detection

Physical To encode the binary digits that represent Data Link layer frames into signals and to transmit

and receive these signals across the physical media provides the means to transport across the network media the bits that make up a Data Link

layer frame to create the electrical, optical, or microwave signal that represents the bits in each frame

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Layered Architecture- OSI Model

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TCP/IP Model

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Applications

The Interface Between Human and Data Networks

applications provide the means for generating and receiving data that

can be transported on the network

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Applications

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Applications

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Domain Name System

Resolving DNS addresses

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DNS

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WWW Services and HTTP

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WWW Services and HTTP

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WWW Services and HTTP

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E-mail and SMTP/POP Protocols

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E-mail and SMTP/POP Protocols

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E-mail and SMTP/POP Protocols

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Telnet

Remote connection Used in examining and managing networks

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Server Message Block (SMB)

SMB protocol is used in supporting file sharing in Microsoft-based networks

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Transport Layer Role and Services

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Transport Layer Role and ServicesUDP TCP

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Network Layer and Internet Protocol (IP)

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IPv4 protocol

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Network Addressing

A way to identify and locate the source and destination Physical addressing

network interface has a physical address assigned to it when it is manufactured

the Media Access Control (MAC) address 48-bit address space : 01-23-45-67-89-ab, 01:23:45:67:89:ab,

0123.4567.89ab (hexadecimal format)

Logical addressing An IP address is assigned to the Network interface connection for a host 32 binary into four 8 bytes each octet is presented as its decimal value, separated by a decimal point

or period 192.168.1.1

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Physical Addressing

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Physical Addressing

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Logical (IP) Addressing

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IP Addressing –Hierarchical

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IP Addressing –Subnet Mask

Differentiate network and host part of an IP address

32 bits long1s represent the network portion and 0’s

represents host portion192.168.1.1 255.255.255.0

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IP Addressing –Subnet Mask

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IP Address Classes

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IP Address –Private Addresses

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Unicast, Multicast, Broadcast

Hosts can use IP addresses to communicate one-to-one (unicast)one-to-many (multicast) one-to-all (broadcast)

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Unicast

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Broadcast

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Multicast

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Static IP Address Assignment

network administrator must manually configure the network information for a host

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Dynamic IP Address Assignment

IP addresses assigned automatically using Dynamic Host Configuration Protocol (DHCP).

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IPv6

128-bit hierarchical addressing - to expand addressing capabilities

Header format simplification - to improve packet handling Improved support for extensions and options - for

increased scalability/longevity and improved packet handling

Flow labelling capability - as QoS mechanisms Authentication and privacy capabilities - to integrate

security