Computer Network Tutorial

Introduction of Computer Network Types of Computer Network Network Topology Computer Networking Architecture Transmission Modes (Data Flow) Basic Networking Devices Integrate Services Digital Network (ISDN)

Model

OSI Model TCP/IP Model

Physical Layer

Digital Transmission Analog Transmission Transmission Media Switching

Data Link Layer

Error detection and Error correction Data Link Control Multiple Access Aloha

Network Layer

Network Layer - Logical Address Address Mapping Unicast Routing Protocol

Transport Layer

Process to Process Delivery User Datagram Protocol Transmission Control Protocol Stream Control Transmission Protocol Session Layer and Presentation Layer

Application Layer

Domain Name System Application Protocol E-mail Cryptography

Misc

Classes of Routing Protocols Classification of Routing Algorithms Controlled Access Protocols in Computer Networks Differences between IPv4 and IPv6 Fixed and Flooding Routing Algorithms Advantages and Disadvantages of Fibre Optics Cable APIPA Difference between Active and Passive FTP Fiber Optics and its Types Method of Joining and Fusion of Fiber Optic Cable Define Framing in Computer Network Disadvantages of Computer Network Mesh Topology Diagram in Computer Network Ring Topology in Computer Network Star Topology in Computer Networks 4G Mobile Communication Technology Advantages and Disadvantages of LAN Advantages and Disadvantages of MAN Advantages and Disadvantages of WAN Application Layer in OSI Model Cyclic Redundancy Check Example Data link layer in OSI model Difference between Transport and Network Layer Hamming Code Example Network Layer in OSI Model Session Layer in OSI Model Transport Layer in OSI Model Two Port Network in Computer Networks Uses of Computer Networks What is Computer Network What is Framing in a Computer Network Advantages and Disadvantages of Bus Topology Difference between Star Topology and Bus Topology Subnetting in Computer Network Subnetting Questions and Answers What is Bus Topology What is Network Topology and Types in Computer Networks Access Control in Networking Basic Characteristics of Computer Network Benefits of SOCKS5 Proxy in Computer Networks Computer Network viva Questions Difference between BOOTP and RARP Difference Between Network Topologies and Network Protocols Difference between NFC and RFID Difference Between Point-to-Point Link and star Topology Network Differences Between MSS and MTU Differences Between Trunk Port and Access Port Different Modes of Communication in Computer Networks MIME Protocol in Computer Networks Modes of Communication in Computer Networks Network Attack in Computer Network Port Address in Networking Simplest Protocol in Computer Network Sliding Window Protocol in Computer Network Stop And Wait Protocol in Computer Networks TCP 3-Way Handshake Process in Computer Networks What is a Proxy Server What is APPN What is ICMP Protocol What is Point-to-Point Protocol What is Port Address in Networking What is the HDLC Protocol What is VRRP Protocol Difference Between Analog and Digital Signals Difference Between Hub and Repeater Difference between Repeater and Switch Difference Between Transparent Bridge and Source Routing Bridge Source Routing Bridge in Computer Networks Transparent Bridge in Computer Networks Transport Protocol in Computer Networks Types of CSMA in Computer Networks What is Wired and Wireless Networking Network Security in Computer Network Disadvantages of Extranet Difference Between TELNET and FTP Define Protocol in Computer Networks Guided Transmission Media in Computer Network What is a Gateway in a Computer Network IGMP in Computer Networks LAN Protocols in Computer Networks MAN Meaning in Computer Modulation Techniques in Computer Networks Switching in DCN TCP/IP Applications What is IGMP? What is Modem in Networking What is Non-Persistent CSMA Difference between Cell Splitting and Cell Sectoring Forouzen Computer Network

Unicast Routing Protocol

Unicast Routing Protocol: Unicast is a point to point communication arrangement that only occurs between the sender and receiver.

Routing Information Protocol

RIP is an open standard protocol that can work with any company's router. RIP is a classful routing protocol; therefore, it does not support VLSM (variable length subnet mask).

The RIP is a distance-vector protocol. It is used in small networks. In this, the hop count is used as a matrix to determine the most appropriate path (s). So that data packets may reach the destination from that path. In this protocol, the maximum number of hops count can only be up to 15. The hop count 16 is considered infinite. The hop count 16 is used to indicate networks that cannot be accessed.

Note: It uses UDP port 250 for the routings table updates.

Distance Vector Routing

Let take an example to understand the distance-vector routing protocol better.

In this example, is a network consisting of four routers A, B, C, and D. The weights are shown in the edges. And the weights could be distances or costs or delays.

Unicast Routing Protocol

Step 1: Every router prepares its routing table using its information. Every table of the router is shown below.

At Router A

DestinationDistanceNext Hop
A0A
B2B
C8C
D1D

At Router B

DestinationDistanceNext Hop
A2A
B0B
C5C
DInfinite-

At Router C

DestinationDistanceNext Hop
A8A
B5B
C0C
D3D

At Router D

DestinationDistanceNext Hop
A1A
BInfinite-
C3C
D0D

Step 2:

  • Every router shares its distance vector with its neighbors obtained in Step-01.
  • Every router prepares a new routing table after exchanging of distance vectors.

At Router A new table:

Unicast Routing Protocol

Cost (A -- B) = 2            Cost (A -- C) = 8            Cost (A -- D) = 1

Cost of reaching destination

B from router A = min {2+0, 8+5, 1+?} = 2 via B.

C from router A = min {2+5, 8+0, 1+3} = 4 via C.

D from router A = min {2+?, 8+3, 1+0} = 1 via D.

DestinationDistanceNext Hop
A0A
B2B
C4D
D1D

At Router B new table:

Unicast Routing Protocol

Cost (B -- A) = 2         Cost (B -- C) = 5 

Cost of reaching destination

A from router B = min {2+0, 5+8} = 2 via A.

C from router B = min {2+8, 5+0} = 5 via C.

D from router B = min {2+1, 5+3} = 3 via D.

DestinationDistanceNext Hop
A2A
B0B
C5C
D3A

At Router C new table:

Unicast Routing Protocol

Cost (C -- A) = 8            Cost (C -- B) = 5            Cost (C -- D) = 3

Cost of reaching destination

A from router C = min {8+0, 5+2, 3+1} = 4 via A.

B from router C = min {8+2, 5+0, 3+?} = 5 via B.

D from router C = min {8+1, 5+?, 3+0} = 3 via D.

DestinationDistanceNext Hop
A4D
B5B
C0C
D3A

At Router D new table:

Unicast Routing Protocol

Cost (D -- A) = 1      Cost (D -- C) = 3

Cost of reaching destination

A from router D = min {1+0, 3+8} = 1 via A.

B from router D = min {1+2, 3+5} = 3 via B.

C from router D = min {1+8, 3+0} = 3 via D.

DestinationDistanceNext Hop
A1A
B3A
C3C
D0D

Final routing tables of every router.

Open Shortest Path First

OSPF is a Link-State routing protocol. It uses SPF (shortest path first) or dikistra algorithm. It is a classless routing protocol; therefore, it supports VLSM (variable length subnet mask). OSPF is a dynamic protocol that takes information (data) from its nearest routers and passes that information to all other routers.