Network Foundations Course 09 WeekOne Orientation

8/14/2019 Network Foundations Course 09 WeekOne Orientation

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Jeevan


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ContentCourse Syllabus

Why Networks

Types of Networks

OSI Reference Model

TCP/IP Reference Model

Transmission Media

Ethernet Extension

Data Transmission

Types of Links

Data Switching

Network Topology

IP Address

Subnet Mask

DNS & DHCP


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Course SyllabusWeek OneNetwork basics

Build a smallnetwork

Week TwoNetwork

Programming

Week ThreeRouting

Routing Algorithmsetc

Week FourProject : File Server

JeevanManjunath .


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Why NetworksSharing of Hardware

Sharing of Software

Sharing of Information

Communication


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Types of NetworksLocal Area Network (LAN):Network within a floor/building/campus

Distance: At most a few kilometers

Wide Area Network (WAN):Country-wide or global network

Distance: 100s or 1000s of kilometers


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OSI Reference Model


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TCP/IP Reference Model

Presentation

Session

Transport

Network

Data Link

Physical

Applicaion

Application

Transport

Internet

Host-to-Network

(Data Link/Physical)

OSI TCP/IP


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Transmission MediaGuided MediaCoaxial CableTwisted pair

Shielded Unshielded

Optical fiber

Unguided Media(wireless)Radio link

Terrestrial microwaveSatellite microwave


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Ethernet ExtensionsRepeaterConnects multiple Ethernet segments

Regenerates the signal (different from amplifier).

Works at Physical layer

HubMultiport repeaters.Signal on any input port is retransmitted on all output ports.

Works at Physical layer

BridgeConnects two parts of a network at the Data Link layer


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Ethernet ExtensionSwitchRepeating signal only on the required output port.MAC address to port number mapping table is build dynamically.

Network management, Virtual LANs.Usually switches works at Data Link Layer Network Layer.

Layer 4 and Layer 7 (Vendor-dependent )

Router

Route data packets between two networks

Works at Network Layer.

Doesnt send broadcast or corrupted packets


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Data TransmissionPoint-to-point linkTwo nodes are connected to each other.

Multi-point link

Broadcasting: Information is sent to all nodes at the same time.

Multicasting: Information is sent to a group of nodes.


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Types of LinksSimplex:Information can be sent only in one direction.

Half-duplex:

Information can be sent in both directionsBut only in one direction at any given time.

Full-duplex:Information can be sent in both directions

simultaneously.


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Data SwitchingCircuit-switched:A channel for data transfer is setup before

communication starts.All resources are reserved.

Packet-switched:Packet is sent to next-hop, where it is stored,

and forwarded to next node.Packets are sent independently through ``store-

and-forward'' mechanism.


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Network TopologiesTopology defines the arrangement of nodes,

cables, and connectivity devices that make upthe network.

Two basic categories:Physical topology:Defines the way the network looks

Logical topology.

Defines the way the data passes among thenodes.


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IP AddressUniquely identify a host on a network.Address convention:Four 8-bit decimal numbers, separated by ``.''

e.g. 144.16.160.2

Has two parts:Net-id and Host-id.


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IP AddressSpecial Addresseshost-id = 0 refers to network rather than a

host.

255.255.255.255 refers to local broadcast.

127.x.y.z is used for loopback address.

Private IP Addresses10.0.0.0 -- 10.255.255.255

172.16.0.0 -- 172.31.255.255192.168.0.0 -- 192.168.255.255


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Subnet MaskIs to separate Net-id from Host-id


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DNS and DHCPDomain Name ServerIt Maps human readable Domain names to

network friendly IP addresses

DHCPDynamically assign IP addresses


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Network Foundations Course 09 WeekOne Orientation

Documents