Inter-Networking Overview

Explain line configuration Explain different types of topologies Explain the types of networks Discuss the modes of transmission Discuss the hierarchical network model Discuss the OSI Layers

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A dedicated link exists between the two devices

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More than two devices share the same link

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Represents the physical layout of devices on a network

It is the arrangement of the devices on the network and the way they communicate with each other

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Bus

Star

RingTree

MeshPhysical Topology

This is used in a small area, an office or organization

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The computers can be connected to each other and other devices, printer or a modem

The rate at which the data is transmitted is very fast

This is used in a large geographical area, town or city Enables high speed connections using fiber optic

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This is used in a larger area than MAN, countries or cities

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Enables high speed connections using public networks, telephone lines, satellites, or leased lines

Only one device can transmit the data, whereas the other can only receive the data

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Both devices can transmit and receive the data, but not simultaneously

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Both the devices can send and receive the data simultaneously

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The topmost layer of the OSI model Link between the user and the presentation layer

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Functions include› Authentication› File access, transfer and management› Directory Services

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Acts as a link between application and the session layer

Defines the forms of text, graphics, video or audio information that is to be sent to the user

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Responsible to validate and establish a connection between the users

Each session is divided into sub sessions Functions include

› Session Management› Synchronization› Dialog Control› Closing the session

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Responsible for source-to-destination delivery of the entire message

divides each message into segments and assigns a sequence number to each segment

Functions include› Service point addressing› End-to-end message delivery› Segmentation and reassembly› Connection control

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Three-Way handshake helps to establish the connection between the two devices

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This concept of deciding the window size without sending an acknowledgement is termed as Windowing

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Responsible for routing and logical addressing Assigns IP addresses and routes the packets to the

destination Functions include

› Source-to-destination delivery› Logical addressing› Routing› Address transformation› Multiplexing

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Second layer of the OSI model Functions include

› Identifying the encapsulated data› Framing› Arbitration› Physical addressing› Error detection

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Responsible for transmitting a bit over the physical medium

Converts the data from the data link layer in a format that the communication medium can carry

Functions include:› Line configuration› Data transmission› Topology› Signals

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Half Duplex Full Duplex

One wire is used to connect the networks and transmit the data

Two wires are used to connect the networks and transmit the data

Chances of collision if client and server transmit data simultaneously

There are no chances of collision

It uses Carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol

CSMA/CD not required hence the data transmission rate is 100 percent

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Frames are used to transfer the packets They perform the data security check and

ensure that the data is not corrupted

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The benefits of Cisco hierarchical model include› High performance› Efficient management and troubleshooting› Policy creation› Scalability› Behavior prediction

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Responsible for fast and reliable transportation of data across a network

Devices include› Cisco Switches in the 7000, 7200, 7500 and

12000 series for connecting to the WAN devices

› Catalyst Switches in the 6000, 5000 and 4000 series for connecting to the LAN devices

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Responsible for routing and managing network traffic

Functions include› Packet filtering› Access layer aggregation point› Control broadcast and multicast› Application gateways

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Layer ensures that the packets are delivered to the destination computers

Functions include› Address filtering› Separate collisions domain› Share bandwidth› Handle switch bandwidth

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Unshielded Twisted Pair (UTP)

Shielded Twisted Pair (STP)

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Line configuration is the manner in which the devices are attached to the communication links

Topology is the way in which the devices are connected together in the network

Two types of line configuration are:› Point-to-point› Multipoint

Five basic topologies include› Bus› Star

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› Ring› Tree› Mesh

The types of network are› Local Area Network› Metropolitan Area Network› Wide Area Network

Modes of transmission › Simplex › Half Duplex› Full Duplex

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The hierarchical network model designed by Cisco provides a reliable, scalable and cost effective way to transfer information

The three layers of the network model are:› Core› Distributional› Access

Core layer is responsible for fast and reliable transportation of data on the network

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Distribution layer is responsible for routing and it manipulates the packets by queuing them

Access layer ensures that the packets are delivered to the destination computers

The Open Systems Interconnection (OSI) is the layered model for the network systems, which enables computers in the network to communicate with each other

Application layer provides an interface for the user to interact with the application

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The seven layers of the OSI model include:› Application› Presentation › Session › Transport› Network› Data Link› Physical

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Presentation layer is responsible for the delivery of information

Session layer controls the communication between the applications on the hosts

Transport layer is responsible for source-to-destination delivery of the entire message

Ethernet Frames are used by the Data Link layer to transfer the packets of data from the Network layer

Physical layer is responsible to transmit a bit over the physical medium

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