Data Communication and Computer Networks – Notes & Tutorials

Assignments

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Assignments

DCN Assignment 1

DCN Assignment 2

Data Communication & Computer Network Assignment 1 Solution in hindi

Data Communication & Computer Network Assignment 2 Solution in hindi(.JPG).

Data Communication and Computer Network Assignment No. 2

DCN Assignments

Routing principles/Issues.

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What is Routing?

Routing is the process of selecting the best or most suitable path for forwarding data packets from a source network to a destination network through one or more routers.
Routing is mainly performed at the Network Layer (Layer 3) of the OSI Model.

Routing Process

Simple Example

 Source Computer
       │
       ▼
    Router R1
       │
       ├────────► Router R2 ───────► Router R4
       │                              │
       └────────► Router R3 ──────────┘
                                      │
                                      ▼
                              Destination Computer

Here, the router has to decide which path should be used to reach the destination.

2. How Does Routing Work?

Suppose a computer with IP address 192.168.1.10 wants to send data to 192.168.4.20.

The router performs the following steps:

Receives the data packet.
Checks the Destination IP Address.
Looks for the destination network in its Routing Table.
Compares available routes using routing metrics.
Selects an appropriate route.
Sends the packet to the Next Hop.

Example Routing Table

Destination Network	Next Hop	Metric
192.168.1.0/24	Direct	0
192.168.2.0/24	Router R2	1
192.168.3.0/24	Router R3	2
192.168.4.0/24	Router R2	3

If the destination is 192.168.4.20, Router R1 can select Router R2 as the next hop.

3. Routing Principles

The major principles of routing are:

3.1 Correctness

The routing algorithm should select a path that can successfully deliver the packet to the correct destination.

Example:

Source → R1 → R2 → Destination
                 ✓
              Correct Path

A router should not forward packets through an unavailable or invalid route.

3.2 Simplicity

The routing mechanism should be simple and efficient.

A simple routing system:

Requires less processing
Uses fewer resources
Is easier to manage
Reduces configuration errors

3.3 Robustness

Robustness means that the routing system should continue to work even when some network components fail.

/ \

Source → R1 R5 → Destination

\ /

If the link through R2 fails, traffic can be redirected through R3.

3.4 Stability

A routing algorithm should not change routes unnecessarily or too frequently.

Frequent route changes may cause:

Routing instability
Extra routing traffic
Delays
Packet loss

A stable routing system provides more predictable network performance.

3.5 Fairness

Routing should provide fair access to network resources.
For example, one connection should not unnecessarily consume all the available capacity of a network path.

3.6 Optimality

The routing algorithm should select an appropriate or optimal path according to its routing metric.

For example:

Path 1:  A → R1 → R2 → B
         3 Hops

Path 2:  A → R3 → R4 → R5 → B
         4 Hops

If hop count is the selected metric, Path 1 may be preferred.
However, the shortest path is not always the fastest path because bandwidth, delay and congestion can also affect route selection.

4. Routing Metrics

A routing metric is a value used by a routing algorithm to compare different routes.
Common routing metrics include:

1. Hop Count

Number of routers a packet must pass through.

2. Bandwidth

Capacity of a network link.

3. Delay

Time required for a packet to travel through a network.

4. Cost

A numerical value assigned to a network path.

5. Reliability

Indicates how dependable a particular link or path is.

6. Load

Amount of traffic currently using a network path.

             Path A
       ┌─────────────────┐
       │                 │
Source ── R1 ── R2 ──────┴──► Destination
       │
       │    Path B
       └──── R3 ── R4 ─────────►

The routing algorithm uses its defined metric(s) to select a suitable route.

5. Routing Issues

Several important issues must be considered while designing a routing system.

5.1 Path Selection

The router must determine which path should be used from source to destination.

                 R2
                /  \
Source → R1 ───     ─── R5 → Destination
                \  /
                 R3

When multiple paths are available, the routing algorithm selects one according to its metrics and rules.

5.2 Routing Table Management

A router maintains a routing table containing information about available routes.

             ROUTER
                │
                ▼
       ┌─────────────────┐
       │  Routing Table  │
       ├─────────────────┤
       │ Destination     │
       │ Next Hop        │
       │ Metric          │
       │ Interface       │
       └─────────────────┘

The router uses this information to determine where the packet should be forwarded.

5.3 Routing Loops

A routing loop occurs when packets continuously travel between routers without reaching their destination.

┌─────────┐

▼ │

R1 ──────► R2

▲ │

│ ▼

└──────── R3

Routing loops can cause:

Wasted bandwidth
Increased network traffic
Packet loss
Network performance problems

5.4 Congestion

Congestion occurs when a network path receives more traffic than it can efficiently handle.

PC1 ──┐
PC2 ──┤
PC3 ──┼──► Router R1 ───► Router R2 ───► Destination
PC4 ──┤                         ▲
PC5 ──┘                         │
                           Heavy Traffic

Congestion can result in:

Increased delay
Packet loss
Reduced throughput
Poor network performance

5.5 Network Failure

Routers, switches, cables or links can fail.
A good routing system should detect the failure and, where possible, use an alternative path.

Normal:

A ── R1 ── R2 ── R3 ── B

After R2 Failure:

A ── R1 ── R4 ── R5 ── R3 ── B

5.6 Scalability

A routing system should work efficiently even when the network becomes very large.
For example, the Internet contains a huge number of networks and routers.

Therefore, routing protocols must efficiently handle:

Large routing tables
Many routers
Frequent network changes
Large amounts of routing information

5.7 Routing Overhead

Routers need to exchange routing information.

       Routing Updates
       ↔          ↔
      R1 ───────── R2
       │            │
       ↕            ↕
      R3 ───────── R4

This exchange consumes:

Bandwidth
CPU resources
Memory

Therefore, routing protocols should minimize unnecessary routing updates.

5.8 Security

Routing information can be manipulated by unauthorized users or malicious devices.

Possible security issues include:

Fake routing information
Unauthorized route changes
Traffic redirection
Routing-table manipulation

Therefore, secure routing mechanisms and authentication can be important in network design.

6. Static and Dynamic Routing

Static Routing	Dynamic Routing
Routes are manually configured	Routes are learned automatically
Suitable for small/simple networks	Suitable for larger networks
No routing-protocol update traffic	Routing information is exchanged
Administrator must update routes	Routes can adapt to network changes
Simple to understand	More complex
Less protocol overhead	More protocol overhead

Examples of Dynamic Routing Protocols

RIP – Routing Information Protocol
OSPF – Open Shortest Path First
EIGRP – Enhanced Interior Gateway Routing Protocol
BGP – Border Gateway Protocol

7. Complete Routing Process

The complete routing process can be represented as:

SOURCE

│

▼

Create Data Packet

│

▼

Destination IP Address

│

▼

ROUTER

│

▼

Check Routing Table

│

▼

Select Suitable Route

│

▼

Next Hop

│

▼

Forward the Packet

│

▼

Another Router

│

▼

DESTINATION

8. Important Points for BTEUP Exam

Routing Principles

Correctness
Simplicity
Robustness
Stability
Fairness
Optimality

Routing Issues

Path Selection
Routing Table Management
Routing Metrics
Routing Loops
Congestion
Network Failure
Scalability
Routing Overhead
Security

Exam Definition

Routing is the process of determining and selecting a suitable path for forwarding data packets from a source network to a destination network through one or more intermediate routers.

In short:
Routing = Destination IP → Routing Table → Route Selection → Next Hop → Packet Forwarding → Destination.

Network Layer – Design Issues

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Network Layer – Design Issues

The Network Layer is the third layer (Layer 3) of the OSI model.
Its main responsibility is to deliver packets from the source network to the destination network, even when multiple networks and routers exist between them.

Basic Network Layer Diagram

┌──────────────┐
│ Source Host  │
│ 192.168.1.10 │
└──────┬───────┘
       │
       ▼
  ┌─────────┐       ┌─────────┐       ┌──────────────┐
  │ Router 1│ ────► │ Router 2│ ────► │Destination   │
  └─────────┘       └─────────┘       │Host          │
                                      │192.168.3.10   │
                                      └──────────────┘

             NETWORK LAYER
       Provides packet delivery
       across multiple networks

What are Network Layer Design Issues?

Network Layer design issues are the important problems and decisions that must be considered while designing the Network Layer so that packets can be delivered efficiently, reliably, and correctly.

The major design issues are:

Store-and-Forward Packet Switching
Services Provided to the Transport Layer
Implementation of Connectionless Service
Implementation of Connection-Oriented Service
Routing
Congestion Control
Quality of Service (QoS)
Internetworking
Fragmentation and Reassembly

1. Store-and-Forward Packet Switching

A router generally receives a packet, stores it temporarily, examines its header, and then forwards it to the next router.
This process is called Store-and-Forward Packet Switching.

Diagram

       Packet
         │
         ▼
┌────────────────┐
│    Router 1    │
│    Receive     │
│    Store       │
│    Forward     │
└───────┬────────┘
        │
        ▼
┌────────────────┐
│    Router 2    │
│    Receive     │
│    Store       │
│    Forward     │
└───────┬────────┘
        │
        ▼
   Destination

The router normally does not forward the packet until it has received enough information to process it.

2. Services Provided to the Transport Layer

The Network Layer provides services to the Transport Layer (Layer 4).
The service should define how packets are delivered from source to destination.

Two important approaches are:

Connectionless Service

Each packet is treated independently.

Packet 1 ──► Router ──► Destination
Packet 2 ──► Router ──► Destination
Packet 3 ──► Router ──► Destination

This is commonly associated with the datagram approach.

Connection-Oriented Service

A logical connection is established before data transfer.

Connection Setup
       ↓
Data Transfer
       ↓
Connection Release

3. Routing

Routing is one of the most important functions of the Network Layer.
Routing determines the path that packets should take from source to destination.

Example

             ┌─────────┐
        ┌───►│ Router 1│───┐
        │    └─────────┘   │
        │                  ▼
Source ─┤              ┌─────────┐
        │              │ Router 3│ ───► Destination
        │              └─────────┘
        │                  ▲
        │    ┌─────────┐   │
        └───►│ Router 2│───┘
             └─────────┘

The routing algorithm selects an appropriate path.
Examples of routing protocols include:

RIP
OSPF
BGP

4. Congestion Control

Congestion occurs when too many packets are present in a network and the network cannot handle the traffic efficiently.

Diagram

PC1 ──┐
PC2 ──┤
PC3 ──┼────► Router ─────► Destination
PC4 ──┤       ▲
PC5 ──┘       │
          Too much traffic
               ↓
            Congestion

Congestion can result in:

Packet loss
Increased delay
Reduced network performance

Therefore, the Network Layer needs mechanisms to manage congestion.

5. Quality of Service (QoS)

Quality of Service (QoS) refers to techniques used to provide appropriate network performance for different types of traffic.

Important QoS parameters include:

Bandwidth
Delay
Jitter
Packet loss

For example, voice and video applications can be sensitive to delay and jitter.

Voice/Video ──► Network ──► Destination
                  │
                  ▼
             QoS Management

6. Internetworking

Different networks may use different technologies and characteristics.
The Network Layer helps connect these different networks into an internetwork.

 LAN 1              WAN              LAN 2

┌─────────┐      ┌─────────┐      ┌─────────┐
│ PCs     │─────►│ Routers │─────►│ Servers │
│ Network │      │         │      │ Network │
└─────────┘      └─────────┘      └─────────┘

IP is the major protocol used to provide internetworking across heterogeneous networks.

7. Fragmentation and Reassembly

Sometimes a packet may be larger than the Maximum Transmission Unit (MTU) supported by a network.
The packet may need to be fragmented according to the protocol and network conditions.

IPv4

In IPv4, fragmentation can be performed by the source or routers, depending on the packet and configuration.

             Large Packet
                  │
                  ▼
              ┌───────┐
              │Router │
              └───┬───┘
                  │
           ┌──────┼──────┐
           ▼      ▼      ▼
        Fragment Fragment Fragment
           │      │      │
           └──────┼──────┘
                  ▼
             Destination

IPv6
IPv6 routers do not fragment packets. If fragmentation is required, it is performed by the source using the appropriate IPv6 fragmentation mechanism.

8. Connectionless vs Connection-Oriented Service

Feature	Connectionless	Connection-Oriented
Connection setup	Not required	Required
Packet treatment	Independent	Part of a logical connection
Example concept	Datagram	Virtual circuit
Routing	Packets may be routed independently	Typically associated with an established path/state
Overhead	Generally lower	Generally higher

9. Important Network Layer Design Issues

For examination, remember the following:

              NETWORK LAYER
                    │
       ┌────────────┼────────────┐
       ▼            ▼            ▼
    Routing     Congestion    QoS
                  Control
       │            │            │
       └────────────┼────────────┘
                    ▼
             Internetworking
                    │
                    ▼
             Packet Delivery
                    │
              ┌─────┴─────┐
              ▼           ▼
       Connectionless  Connection-
          Service       Oriented

Short Exam Definition

Network Layer design issues are the major design considerations involved in providing efficient packet delivery across interconnected networks.

They include routing, congestion control, quality of service, internetworking, packet forwarding, service models, and fragmentation.

Key Point

The main goal of the Network Layer is to provide efficient and correct delivery of packets from the source network to the destination network through one or more routers.

IPv6 (Internet Protocol Version 6)

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IPv6 (Internet Protocol Version 6)

1. Introduction to IPv6

IPv6 stands for Internet Protocol Version 6. It is a Network Layer (Layer 3) protocol used to provide addressing and routing for devices connected to an IP network.
IPv6 was developed mainly to overcome the limited address space of IPv4 and to support the continued growth of the Internet.

Basic Diagram

              IPv6 NETWORK

┌──────────────┐
│   Computer   │
│ 2001:db8::10 │
└──────┬───────┘
       │
       │ IPv6 Packet
       ▼
┌──────────────┐
│    Router    │
│ IPv6 Router  │
└──────┬───────┘
       │
       │
       ▼
┌──────────────┐
│    Server    │
│ 2001:db8::20 │
└──────────────┘

The router uses the destination IPv6 address to forward the packet toward the destination network.

2. IPv6 Address

An IPv6 address is 128 bits long.
It is normally represented as eight groups of 16 bits, written in hexadecimal and separated by colons (:).

IPv6 Address Structure

                         128 Bits
┌──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┐
│ 16b  │ 16b  │ 16b  │ 16b  │ 16b  │ 16b  │ 16b  │ 16b  │
└──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┘

  2001 : 0db8 : 0000 : 0000 : 0000 : ff00 : 0042 : 8329

Example

2001:0db8:0000:0000:0000:ff00:0042:8329

Each group contains 4 hexadecimal digits, representing 16 bits.

3. IPv6 Address Shortening

IPv6 provides rules for shortening addresses.

Rule 1: Leading zeros can be removed

0db8 → db8
0042 → 42

Therefore:

2001:0db8:0000:0000:0000:ff00:0042:8329

can become:

2001:db8:0:0:0:ff00:42:8329

Rule 2: Consecutive zero groups can be replaced by `::`

2001:db8:0:0:0:ff00:42:8329

can be written as:

2001:db8::ff00:42:8329

Important: :: should normally be used only once in an IPv6 address.

4. IPv6 Address Structure

An IPv6 address can be logically divided into:

┌───────────────────────────────┬──────────────────────┐
│       Network Prefix          │    Interface ID      │
└───────────────────────────────┴──────────────────────┘
             64 bits                    64 bits

A common IPv6 subnet uses a /64 prefix.

For example:

2001:db8:1234:5678:abcd:ef01:2345:6789
└───────────────┬───────────────┘
       Network Prefix
           64 bits

                         └───────────────┬───────────────┘
                                  Interface ID
                                     64 bits

5. Types of IPv6 Addresses

IPv6 has three main address types.

A. Unicast

A Unicast address identifies a single interface.

Communication is:

One → One

PC ─────────────────► Server
       Unicast

B. Multicast

A Multicast address identifies a group of interfaces.

Communication is:

                 ┌──► PC 1
                 │
Server ──────────┼──► PC 2
                 │
                 └──► PC 3

                Multicast

One sender can send data to multiple receivers that belong to the multicast group.

C. Anycast

An Anycast address can be assigned to multiple interfaces.
Routing delivers the packet to one appropriate destination, typically the nearest according to the routing topology.

                 ┌──► Server 1
                 │
Client ──────────┼──► Server 2
                 │
                 └──► Server 3

                  Anycast

6. IPv6 Does Not Use Broadcast

One important difference from IPv4 is that IPv6 does not use broadcast.

Instead, IPv6 uses mechanisms such as:

Multicast
Anycast

for communication patterns that do not require ordinary unicast.

7. IPv6 Packet Format

An IPv6 packet consists of:

┌─────────────────────────────────────┐
│          IPv6 Base Header           │
│              40 Bytes               │
├─────────────────────────────────────┤
│        Extension Header(s)          │
│             Optional                │
├─────────────────────────────────────┤
│              Payload                │
│               Data                  │
└─────────────────────────────────────┘

The IPv6 base header is fixed at 40 bytes.

8. IPv6 Header

The important fields of the IPv6 header are:

┌──────────────────────────────────────────────┐
│ Version │ Traffic Class │                    │
├─────────┴────────────────────────────────────┤
│              Flow Label                      │
├──────────────────────┬───────────────────────┤
│ Payload Length       │ Next Header           │
├──────────────────────┴───────────────────────┤
│              Hop Limit                       │
├──────────────────────────────────────────────┤
│          Source Address (128 bits)           │
├──────────────────────────────────────────────┤
│       Destination Address (128 bits)         │
└──────────────────────────────────────────────┘

Important Fields

Version: Indicates the IP version. For IPv6, the value is 6.
Traffic Class: Used for traffic classification and handling.
Flow Label: Helps identify packets belonging to a particular flow.
Payload Length: Specifies the length of the payload following the IPv6 base header.
Next Header: Identifies the next header, such as an extension header or transport protocol.
Hop Limit: Limits the number of routers a packet can pass through.
Source Address: IPv6 address of the sender.
Destination Address: IPv6 address of the receiver.

9. IPv6 Communication

             SOURCE                         DESTINATION

       ┌──────────────┐                 ┌──────────────┐
       │      PC      │                 │    Server    │
       │ 2001:db8::10 │                 │ 2001:db8::20 │
       └──────┬───────┘                 └──────▲───────┘
              │                                │
              │         IPv6 Packet            │
              ▼                                │
       ┌──────────────┐                 ┌──────┴───────┐
       │   Router 1   │──────► Router 2 ─►│ Destination │
       └──────────────┘                 └──────────────┘

The routers examine the destination IPv6 address and forward the packet toward the appropriate network.

10. IPv6 Auto-Configuration

IPv6 supports SLAAC (Stateless Address Autoconfiguration).
SLAAC allows a host to automatically configure an IPv6 address in suitable network environments.

             Router
                │
                │ Router Advertisement
                ▼
          ┌────────────┐
          │  Computer  │
          └─────┬──────┘
                │
                ▼
        IPv6 Address
         Configured

IPv6 can also use DHCPv6 when required.

11. Neighbor Discovery Protocol (NDP)

IPv6 uses Neighbor Discovery Protocol (NDP) for discovering and interacting with neighboring nodes on the local link.
NDP is based on ICMPv6.

It can help with:

Neighbor discovery
Router discovery
Address resolution
Neighbor reachability detection
Address configuration support

In IPv4, ARP is commonly used for address resolution. IPv6 uses NDP instead of ARP.

12. Advantages of IPv6

1. Huge Address Space

IPv6 uses 128-bit addresses.
The theoretical address space is of 2¹²⁸
This provides an enormous number of possible addresses.

2. Simplified Base Header

The IPv6 base header has a fixed size of 40 bytes.

3. No Broadcast

IPv6 eliminates broadcast and uses multicast/anycast where appropriate.

4. Auto-Configuration

IPv6 supports automatic address configuration through mechanisms such as SLAAC.

5. Efficient Multicast Support

Multicast is an important part of IPv6 communication.

6. Suitable for Large Networks

The huge address space makes IPv6 suitable for large-scale networks, including modern Internet and IoT deployments.

13. Why Was IPv6 Developed?

The major limitation of IPv4 is its 32-bit address space.

                  IPv4
                    │
                    ▼
                 32 bits
                    │
                    ▼
          Limited Address Space
                    │
                    ▼
             More Devices
                    │
                    ▼
                  IPv6
                    │
                    ▼
                128 bits
                    │
                    ▼
          Huge Address Space

As the number of Internet-connected devices increased, the availability of IPv4 addresses became a major issue. IPv6 provides a vastly larger address space.

14. Example of IPv6 in a College Network

Suppose a college has several computers and a server:

                 COLLEGE IPv6 NETWORK

       ┌─────────────────┐
       │   Computer 1    │
       │ 2001:db8:1::10  │
       └────────┬────────┘
                │
         ┌──────▼──────┐
         │   Switch    │
         └──────┬──────┘
                │
         ┌──────▼──────┐
         │    Router   │
         │ 2001:db8:1::1│
         └──────┬──────┘
                │
         ┌──────▼──────┐
         │    Server   │
         │ 2001:db8:1::20│
         └─────────────┘

The computer can send an IPv6 packet to the server using the server's IPv6 address as the destination address.

15. IPv6 vs IPv4 — Important Comparison

16. Quick Revision Diagram

                         IPv6
                          │
              ┌───────────┴───────────┐
              │                       │
          128-bit Address          Layer 3
              │                       │
       Hexadecimal Format          Routing
              │
      ┌───────┼────────┐
      │       │        │
   Unicast Multicast Anycast
      │
      └─────────────────────┐
                            │
                     No Broadcast
                            │
                 ┌──────────┴──────────┐
                 │                     │
               SLAAC                  NDP
          Auto Configuration    Neighbor Discovery

Exam Definition

IPv6 (Internet Protocol Version 6) is a 128-bit Network Layer protocol that provides addressing and routing for IP networks.

It was developed primarily to provide a vastly larger address space than IPv4 and includes features such as multicast, SLAAC, and Neighbor Discovery Protocol (NDP).

Key point to remember:
IPv4 = 32-bit address
IPv6 = 128-bit address

Advantages of IPv6

Realtime Data Transmission: There is very little latency in the transmission of data. For instance, live broadcasting of sporting events with a five to six second lag.
IPv6 authentication verifies that data is authentic and hasn't been tampered with. For instance, utilizing hash values to verify messages.
IPv6 Encryption: Provides inherent security by encrypting communications at the network layer even when the application layer does not.
Faster Router Processing: Compared to IPv4's 20–60 byte variable header, IPv6's fixed 40-byte header enables routers to process packets more quickly.

Disadvantages of IPv6

Transition Period: It will take a while to fully switch to IPv6 because IPv4 is still widely used.
Communication Barrier: Direct communication between IPv4 and IPv6 machines is not possible.
No Backward Compatibility: Because IPv4 systems do not support IPv6, IPv6 cannot operate on computers that support IPv4.
Conversion Challenges: The switch from IPv4 to IPv6 is time-consuming due to IPv6's inability to uniquely identify every device on the network.
Protocol Isolation: Direct communication between IPv4 and IPv6 is impossible, making cross-protocol communication impossible.

Concept of IPv4

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Concept of IPv4

IPv4 (Internet Protocol Version 4) is the most widely known traditional version of IP. It uses a 32-bit address to identify a device/interface on an IP network.

IPv4 Address Structure

A 32-bit IPv4 address is divided into four 8-bit parts, called octets.

32 Bits
┌────────┬────────┬────────┬────────┐
│ 8 Bits │ 8 Bits │ 8 Bits │ 8 Bits │
├────────┼────────┼────────┼────────┤
│  192   │  168   │   1    │   10   │
└────────┴────────┴────────┴────────┘

        192.168.1.10

Each octet can have a value from:

0 to 255

Therefore, an IPv4 address looks like:

192.168.1.10

This notation is called dotted-decimal notation.

IPv4 Communication Diagram

┌──────────┐                         ┌──────────┐
│ Computer │                         │ Server   │
│192.168.1.10                       │8.8.8.8  │
└────┬─────┘                         └────▲─────┘
     │                                    │
     │        IP Packet                   │
     └──────────────► Router ─────────────┘
                    │
             Finds destination
             using IP address

The router examines the destination IP address and forwards the packet toward the appropriate network.

2. IPv4 Addressing

IPv4 addresses have two logical parts:

IPv4 Address
┌─────────────────────┬──────────────────┐
│     Network Part    │    Host Part     │
└─────────────────────┴──────────────────┘

For example, with a /24 prefix:

192.168.1.10/24

Network Part          Host Part
───────────────       ─────────
192.168.1             10

The /24 means that the first 24 bits represent the network prefix.

3. IPv4 Private Addresses

Some IPv4 address ranges are reserved for use inside private networks.

Range	Typical Use
10.0.0.0/8	Private network
172.16.0.0/12	Private network
192.168.0.0/16	Private network

Example:

PC 1 → 192.168.1.10
PC 2 → 192.168.1.20
Router → 192.168.1.1

These addresses are commonly used in homes, colleges, offices and laboratories.

4. Limitations of IPv4

The biggest limitation of IPv4 is its limited address space.

IPv4 has:

32 bits

Therefore, the theoretical number of addresses is:

2³² = 4,294,967,296

Not all of these are usable as ordinary host addresses because some ranges have special purposes.

With the growth of:

Computers
Smartphones
IoT devices
Servers
Smart TVs
Industrial devices
The demand for IP addresses increased greatly.

This was one of the major reasons for developing IPv6.

Parts of IPv4

Three components make up an IPv4 address:

Network Part:

The unique variation assigned to the network is indicated by the network part. The designated network category is jointly identified in the network section.

Host Part:

The machine on your network is uniquely identified by the host part. Each host is given this portion of the IPv4 address.
The network portion is the same for every host on the network, but the host portion needs to change.
The optional component of IPv4 is the subnet number. Subnet numbers are assigned to local networks with a large number of hosts.

Types of IPv4 Addressing

IPv4 basically supports three different types of addressing modes

Unicast Addressing method:

This addressing method designates a single sender and a single recipient. For instance, visiting a webpage.

Broadcast Addressing Mode:

Sending messages to every device in a network is done via the broadcast addressing option. Sending a message to every device on a local network is one example.

Multicast Addressing Mode:

This addressing mode transmits messages to a collection of devices and is commonly used within a local network or across networks. For instance, simultaneously streaming audio to several devices.

IPv4 Datagram Header

These fields together ensure the proper delivery, routing, fragmentation, and reassembly of IP packets across the network.

VERSION: Version of the IP protocol (4 bits), which is 4 for IPv4
HLEN: IP header length (4 bits), which is the number of 32 bit words in the header. The minimum value for this field is 5 and the maximum is 15.
Type of service: Low Delay, High Throughput, Reliability (8 bits)
Total Length: Length of header + Data (16 bits), which has a minimum value 20 bytes and the maximum is 65,535 bytes.
Identification: Unique Packet Id for identifying the group of fragments of a single IP datagram (16 bits)
Flags: 3 flags of 1 bit each : reserved bit (must be zero), do not fragment flag, more fragments flag (same order)
Fragment Offset: Represents the number of Data Bytes ahead of the particular fragment in the particular Datagram. Specified in terms of number of 8 bytes, which has the maximum value of 65,528 bytes.
Time to live: Datagram’s lifetime (8 bits), It prevents the datagram to loop through the network by restricting the number of Hops taken by a Packet before delivering to the Destination.
Protocol: Name of the protocol to which the data is to be passed (8 bits)
Header Checksum: 16 bits header checksum for checking errors in the datagram header
Source IP address: 32 bits IP address of the sender
Destination IP address: 32 bits IP address of the receiver
Option: Optional information such as source route, record route. Used by the Network administrator to check whether a path is working or not.

Characteristics of IPv4

IPv4 could be a 32-bit IP Address.
IPv4 could be a numeric address, and its bits are separated by a dot.
The number of header fields is twelve and the length of the header field is twenty.
It has Unicast, broadcast, and multicast-style addresses.
IPv4 supports VLSM (Virtual Length Subnet Mask).
IPv4 uses the Post Address Resolution Protocol to map to the MAC address.

Advantages of IPv4

IPv4 security permits encryption to keep up privacy and security.
IPV4 network allocation is significant and presently has quite 85000 practical routers.
It becomes easy to attach multiple devices across an outsized network while not NAT.
This is a model of communication so provides quality service also as economical knowledge transfer.
IPV4 addresses are redefined and permit flawless encoding.

Limitations of IPv4

IP relies on network layer addresses to identify end-points on the network, and each network has a unique IP address.
The world's supply of unique IP addresses is dwindling, and they might eventually run out theoretically.
If there are multiple hosts, we need the IP addresses of the next class.
Complex host and routing configuration, non-hierarchical addressing, difficult to re-numbering addresses, large routing tables, non-trivial implementations in providing security, QoS (Quality of Service), mobility, and multi-homing, multicasting, etc. are the big limitations of IPv4 so that's why IPv6 came into the picture.

Network Management System and example protocol (SNMP)

2026-09-25T11:33:11.682+05:30

What is Network Management System?

A Network Management System (NMS) is a software system used by network administrators to monitor, manage, configure, and troubleshoot network devices such as routers, switches, servers, access points, and firewalls.

An NMS helps the administrator know:

Whether a network device is working or not
How much bandwidth is being used
Whether there are errors or failures
CPU and memory utilization of devices
Network traffic and performance
When a device goes down or comes back up

Basic NMS Diagram

                  NETWORK MANAGEMENT SYSTEM
                         (NMS Server)
                              │
                    ┌─────────┴─────────┐
                    │                   │
                  SNMP                 SNMP
                    │                   │
             ┌──────▼──────┐     ┌──────▼──────┐
             │   Router    │     │   Switch    │
             │ SNMP Agent  │     │ SNMP Agent  │
             └─────────────┘     └─────────────┘
                    │                   │
                    │                   │
              ┌─────▼─────┐       ┌─────▼─────┐
              │  Server   │       │  Access   │
              │SNMP Agent │       │   Point   │
              └───────────┘       │SNMP Agent │
                                  └───────────┘

The NMS Server communicates with network devices and collects information about their status and performance.

2. What is SNMP?

SNMP stands for Simple Network Management Protocol.

It is an application-layer protocol used to monitor and manage network devices over an IP network.

SNMP is commonly used with:

Routers
Switches
Servers
Printers
Firewalls
Wireless Access Points
UPS systems

SNMP generally uses UDP for communication.

UDP Port 161 → Used for SNMP queries/responses
UDP Port 162 → Used for SNMP Trap messages

3. SNMP Architecture

SNMP mainly consists of three important components:

1. SNMP Manager

The SNMP Manager is usually part of the NMS.

It requests and receives information from network devices.

2. SNMP Agent

An SNMP Agent is software running on a managed network device.

It collects information about the device and provides that information to the SNMP Manager.

3. MIB

MIB stands for Management Information Base.

It is a structured collection of information/objects that can be monitored or managed through SNMP.

Examples:

Device uptime
Interface status
Number of received packets
Number of transmitted packets
Error counts
CPU-related information, when exposed by the device

4. SNMP Architecture Diagram

                    ┌─────────────────────────┐
                    │    Network Manager      │
                    │        / NMS            │
                    │    (SNMP Manager)       │
                    └────────────┬────────────┘
                                 │
                         SNMP Messages
                                 │
                    ─────────────┼─────────────
                                 │
              ┌──────────────────┼──────────────────┐
              │                  │                  │
        ┌─────▼─────┐      ┌─────▼─────┐      ┌─────▼─────┐
        │  Router   │      │  Switch   │      │  Server   │
        │SNMP Agent │      │SNMP Agent │      │SNMP Agent │
        └─────┬─────┘      └─────┬─────┘      └─────┬─────┘
              │                  │                  │
           ┌──▼──┐            ┌──▼──┐            ┌──▼──┐
           │ MIB │            │ MIB │            │ MIB │
           └─────┘            └─────┘            └─────┘

5. How SNMP Works

Suppose a network administrator wants to know whether a router's interface is working.

Step 1: NMS sends a request

The SNMP Manager sends a GET request to the router's SNMP Agent.

NMS / Manager
      │
      │ SNMP GET
      ▼
  ┌───────────┐
  │  Router   │
  │SNMP Agent │
  └───────────┘

Step 2: Agent checks the information

The SNMP Agent looks at the required object in its MIB.

Step 3: Agent sends response

The agent sends the requested information back to the NMS.

NMS / Manager
      ▲
      │ SNMP RESPONSE
      │
  ┌───────────┐
  │  Router   │
  │SNMP Agent │
  └───────────┘

The NMS can then display the information to the administrator.

6. Important SNMP Operations

1. GET

Used by the manager to request information from an SNMP agent.

Manager ───── GET ─────► Agent
Manager ◄── RESPONSE ── Agent

Example:
"Tell me the status of interface 1."

2. GETNEXT

Used to retrieve the next object in the MIB hierarchy.

It is useful when walking through a group of MIB objects.

3. GETBULK

Used to retrieve large amounts of management information efficiently.

It is mainly associated with SNMPv2c and SNMPv3.

4. SET

Used by the manager to change a configurable value on a device.

Manager ───── SET ─────► Agent
Manager ◄── RESPONSE ── Agent

Example:

Changing a configurable network parameter, if the device permits it.

5. TRAP

A Trap is an unsolicited message sent by the SNMP Agent to the Manager when an important event occurs.

For example:

Router
  │
  │ Interface Down
  ▼
SNMP Agent
  │
  │ SNMP TRAP
  ▼
NMS
  │
  ▼
Administrator Alert

6. INFORM

Inform is similar to a Trap, but it requires an acknowledgment from the receiver.

7. SNMP Message Flow

                    ┌──────────────────┐
                    │       NMS        │
                    │ SNMP Manager     │
                    └────────┬─────────┘
                             │
                 ┌───────────┼───────────┐
                 │           │           │
                GET         SET       GETBULK
                 │           │           │
                 ▼           ▼           ▼
              ┌────────────────────────────┐
              │       Network Device       │
              │       SNMP Agent           │
              │                            │
              │            MIB             │
              └─────────────┬──────────────┘
                            │
                       TRAP / INFORM
                            │
                            ▼
                           NMS

8. Example of SNMP in a College Network

Suppose a college has:

2 Routers
10 Switches
3 Servers
20 Access Points

The administrator can install an NMS and enable SNMP agents on the devices.

                         NMS SERVER
                       ┌────────────┐
                       │   SNMP     │
                       │  Manager   │
                       └─────┬──────┘
                             │
                    College Network
                             │
       ┌─────────────┬──────┼──────┬─────────────┐
       │             │      │      │             │
    Router         Switch  Server   AP         Firewall
   SNMP Agent    SNMP Agent  Agent  Agent      Agent

The administrator can monitor:

Device availability
Interface status
Network traffic
Packet errors
Bandwidth utilization
Device uptime
Other supported device statistics

If a switch goes down, the NMS can receive an alert and notify the administrator.

9. SNMP Versions

Version	Important Feature
SNMPv1	Original/basic version
SNMPv2c	Improved operations and performance; community-based security
SNMPv3	Adds stronger security features such as authentication and encryption

For modern deployments, SNMPv3 is generally preferred when supported because it provides security features that older community-string-based versions do not.

10. Advantages of NMS and SNMP

Advantages of NMS

Centralized network monitoring.
Helps detect network failures quickly.
Makes troubleshooting easier.
Provides performance information.
Can generate alerts and reports.
Helps administrators monitor large networks.

Advantages of SNMP

Simple and widely supported.
Works with many types of network devices.
Provides centralized monitoring.
Supports automatic alerts through Trap/Inform.
Helps collect network performance information.

Short Exam Definition

Network Management System (NMS) is a software system used to monitor, manage, configure, and troubleshoot network devices from a centralized location.

SNMP (Simple Network Management Protocol) is an application-layer protocol used to monitor and manage network devices. It uses an SNMP Manager, SNMP Agent, and MIB for network management.

Remember this diagram for exam

             ┌─────────────────┐
             │   NMS / SNMP    │
             │     Manager     │
             └────────┬────────┘
                      │
                 SNMP Messages
                      │
       ┌──────────────┼──────────────┐
       ▼              ▼              ▼
   ┌────────┐     ┌────────┐     ┌────────┐
   │ Router │     │ Switch │     │ Server │
   │ Agent  │     │ Agent  │     │ Agent  │
   └───┬────┘     └───┬────┘     └───┬────┘
       ▼              ▼              ▼
      MIB            MIB            MIB

One-line concept:

NMS = System used for network monitoring and management; SNMP = Protocol used by NMS to communicate with network devices.

Bridge in Computer Network

2026-09-25T11:03:15.597+05:30

Bridge in Computer Network

A Bridge is a networking device that connects two or more LAN segments and forwards data between them. It works mainly at the Data Link Layer (Layer 2) of the OSI Model.
It uses MAC addresses to decide whether a frame should be forwarded or filtered while operating at the Data Link Layer (Layer 2) of the OSI architecture.
A bridge helps cut down on pointless traffic and enhance network performance by splitting a network into several collision domains.
Bridging is the process of utilizing a bridge to connect network parts.

Diagram

Types of Bridges

There are three types of bridges in computer networks, which are as follows

Transparent Bridge: Other networked devices cannot see transparent bridges. When a station is added or removed, this bridge does not reconfigure the network. The primary purpose of the transparent bridge is to either forward or block data based on the MAC address.
Source Routing Bridge: IBM created source routing bridges especially for token ring networks. The source station performs the routing operation by embedding the frame's whole route with the data frames, requiring the frame to follow a predetermined path or route once it is forwarded.
Translational Bridge: Translational bridges transfer data from one networking system to another. Alternatively, it is employed for data transmission or communication between two distinct kinds of networking systems.

How Does a Bridge Work?

A bridge examines the MAC address of incoming data frames and decides whether the frame should be:

Forwarded to another network segment.
Filtered if the destination is on the same segment.

For example:

PC1 ─── LAN 1 ─── Bridge ─── LAN 2 ─── PC3
                     │
              Checks MAC Address

If PC1 sends data to PC3, the bridge checks PC3's MAC address and forwards the frame to LAN 2.
If PC1 sends data to PC2 and both are on LAN 1, the bridge can filter the frame instead of sending it to LAN 2.

Main Functions of a Bridge

Connects LAN segments.
Works at the Data Link Layer (Layer 2).
Uses MAC addresses to make forwarding decisions.
Filters unnecessary traffic.
Helps reduce network traffic and collisions.
Learns and maintains a MAC address table.

Simple Example

Imagine two classrooms connected through a bridge:

Classroom A                    Classroom B
PC1 ── PC2 ──┐              ┌── PC3 ── PC4
             │              │
             └── BRIDGE ────┘

Advantages:-

The bridge allows computers in both classrooms to communicate while preventing unnecessary traffic from being transmitted to the other classroom.
Bridges can serve as a network extension by joining two different network topologies.
It has more bandwidth because it has a distinct collision domain.
When distinct MAC protocols are present for various segments, it may generate a buffer.
incredibly dependable and maintained. There are several LAN segments that can be created from the network.
Easy to install, using only the bridge itself and no additional hardware or software.
The transparency of the protocol is greater than that of other protocols.

Disadvantages:-

Costly in comparison to repeaters and hubs.
Reduce your speed.
Poor performance because viewing the network device's MAC address requires additional processing.
Individual data filtering is not feasible because the traffic is broadcast or received in large quantities.
The network experiences heavy broadcast traffic while data is being broadcast, and broadcast storms may develop.

Bridge vs Switch

A switch can be considered a more advanced version of a bridge. A traditional bridge usually connects a small number of network segments, whereas a switch commonly provides many ports and performs the same basic Layer-2 forwarding function.

In short:

A Bridge is a Layer-2 networking device that connects LAN segments and forwards or filters frames using MAC addresses.

Computer Network

2026-09-19T11:38:59.785+05:30

UNIT 1: Introduction

UNIT 2: Data Communication and Communication Methodologies

UNIT 3: Network Layer

UNIT 4: Transport Layer

Transport Layer – Design issues.
Protocols: TCP and UDP.
Application Layer Protocols (SMTP, DNS)

UNIT 5: Network Devices

Functioning of Network Devices –

NIC.
Hub.
Bridge.
Switch.
Router.
WiFi Devices
NetworkManagement System and example protocol (SNMP).

Wi-Fi 6 vs Wi-Fi 7 Technologies

2025-07-02T15:10:00.003+05:30

🚀 Wi-Fi 6 (802.11ax)

Faster Speeds: Up to 9.6 Gbps (compared to 3.5 Gbps in Wi-Fi 5)
Better Performance in Crowded Areas: Ideal for stadiums, airports, offices, etc.
OFDMA (Orthogonal Frequency Division Multiple Access): Splits channels into smaller sub-channels for efficient bandwidth sharing
MU-MIMO (Multi-User Multiple Input, Multiple Output): Supports multiple devices simultaneously
TWT (Target Wake Time): Improves battery life in smart devices by reducing idle listening
Improved Security: Uses WPA3 for enhanced protection

Suitable For:

Smart homes
Video streaming (HD/4K)
Online gaming
IoT devices

⚡️ Wi-Fi 7 (802.11be) – The Next Generation

Key Upgrades over Wi-Fi 6:

Faster Speeds: Up to 46 Gbps (approx 5x faster than Wi-Fi 6)
Wider Channels: Supports 320 MHz channels (vs 160 MHz in Wi-Fi 6)
16×16 MU-MIMO: More antennas = more simultaneous device support
Multi-Link Operation (MLO): Devices can connect to multiple bands (2.4 GHz + 5 GHz + 6 GHz) at once — improving speed & reliability
Lower Latency: Ideal for VR, AR, and real-time gaming
Enhanced OFDMA and QAM (up to 4096-QAM): More data packed per signal

In Simple Terms:

Wi-Fi 6 = Efficient + Fast
Wi-Fi 7 = Supercharged Speed + Ultra-Low Latency + Multi-band magic

📊 Quick Comparison Table:

Feature	Wi-Fi 6 (802.11ax)	Wi-Fi 7 (802.11be)
Max Speed	~9.6 Gbps	~46 Gbps
Channel Width	Up to 160 MHz	Up to 320 MHz
Modulation	1024-QAM	4096-QAM
MU-MIMO	8×8	16×16
Multi-Link Operation	❌	✅
Latency	Low	Ultra-Low
Release Timeline	2019	2024–2025 (rolling out)

Wi-Fi 6 vs Wi-Fi 7 Technologies

Summary:

Wi-Fi 6 improved speed, stability, and device management.
Wi-Fi 7 is designed for the future: smart cities, AR/VR, 8K streaming, industrial IoT, and high-demand real-time applications.

Classful Addressing in IP Addressing

2024-10-09T14:16:00.002+05:30

Benchmark	Physical Address	Logical Address
Representation	Represents the actual physical location of data in memory or devices	A virtual or symbolic representation of memory locations, used by software programs
Generation	Generated based on the hardware architecture and memory configuration	Generated by the CPU while a program is running
Address Translation	Used directly by hardware to access memory locations, no translation required	Must be translated or mapped to its corresponding physical address by the Memory Management Unit (MMU) before being used by hardware
Address Space	Limited by the amount of installed physical memory in the system	Can be part of a larger virtual address space, exceeding the available physical memory
Portability	Tied to a specific hardware architecture and memory layout, not portable across systems	More portable across different systems and architectures, as long as the address translation mechanisms are compatible
Purpose	Directly accessed by hardware components for low-level operations and efficient data transfer	Used by software programs and operating systems for memory management, memory protection, and efficient resource sharing
Abstraction Level	Low-level, hardware-specific addresses	Higher-level, software-friendly addresses
Mapping	No mapping required, directly used by hardware	Mapped or translated to physical addresses by the MMU
Memory Access	Provides direct access to physical memory locations	Provides an abstraction layer over physical memory access
Memory Management Features	Limited memory management features	Enables features like virtual memory, demand paging, swapping, and shared memory

An IP address is a number that contains information about a host's location, particularly when it's not within a local area network. An IP address is a unique 32-bit address with 232 address space.
Hexadecimal notation and dotted decimal notation are the two common notations used to write IP addresses.

Dotted Decimal Notation

Hexadecimal Notation

Observations regarding dotted decimal notation

Any segment's (byte's) value falls between 0 and 255 (both included).
In every segment, the value comes before any zeros (054 is incorrect, 54 is correct).

Classful Addressing

The 32-bit IP address is divided into five sub-classes. These are:

Class A
Class B
Class C
Class D
Class E
There is a suitable range of IP addresses for each of these classes. For multicast and experimental reasons, respectively, classes D and E are set aside.
The IP address's classes are determined by the bits in the first octet.
The IPv4 address is divided into two parts:

Network ID
Host ID

The bits used for network ID and host ID, as well as the total number of networks and hosts that can be included in that specific class, are determined by the class of IP address.
Every device connected to a network is given an IP address by the network administrator or ISP.

Note:-

Regional Internet registries (RIR) and the Internet Assigned Numbers Authority (IANA) oversee IP addresses internationally.
Since the last IP address is allocated for broadcast IP and the first IP address of any network is the network number, two IP addresses are not counted when determining the total number of host IP addresses. As a result, the total count is dropped.

Class A

Large numbers of hosts are found on networks that are assigned class A IP addresses.

The network ID consists of 8 bits.
The host ID consists of 24 bits.
In class A, the first octet's higher-order bit is always set to 0.
The network ID is determined by the final 7 bits of the first octet.
Any network's host can be identified using the 24 bits of the host ID.
For Class A, the default subnet mask is 255.x.x.x. As a result, class A's total is:

Class A host ID IP addresses range from 1.0.0.0 to 126.255.255.255.
2^24 – 2 = 16,777,214.

Class B

Networks ranging in size from medium-sized to large-sized are issued IP addresses under class B.

The network ID consists of 16 bits.
The host ID consists of 16 bits.
Class B IP addresses always have their first octet's higher-order bits set to 10.
The network ID is found using the final 14 bits.
Any network's host can be identified using the 16 bits of the host ID. Class B's default subnet mask is 255.255.x.x.

For Class B, the total is: 2^14 = 16384 network address 2^16 – 2 = 65534 host address
Class B IP addresses start at 128.0.0.0 and go up to 191.255.255.255.

Class C

Class C IP addresses are given to networks with less than ten users.

The network ID consists of 24 bits.
The host ID consists of 8 bits.
IP addresses belonging to class C always have their first octet's higher-order bits set to 110. The network ID is found using the final 21 bits.
Any network's host can be identified using the eight bits of the host ID.

Class C's default subnet mask is 255.255.255.x.
In total, Class C possesses: 2^21=2097152 network address.
IP addresses that belong to class C range from 192.0.0.0 to 223.255.255.255.
2^8 – 2 = 254 host addresses.

Class D

Class D IP addresses are set aside for multicasting. Class D IP addresses always have their first octet's higher-order bits set to 1110.
The addresses that interested hosts recognize are represented by the remaining bits.
There is no subnet mask in Class D.
Class D IP addresses fall between 224.0.0.0 to 239.255.255.255.

Class E

Class E IP addresses are set aside for use in experimentation and research.
The range of class E IP addresses is 240.0.0.0 to 255.255.255.254.
There isn't a subnet mask for this class. Class E's first octet's higher-order bits are always set to 1111.

Different Classes

Rules for Assigning Host ID

Within a network, hosts are identified by their host IDs. The following guidelines are used to assign the host ID:
Any network requires the host ID to be exclusive to that network.
Since this host ID is used to indicate the network ID of the IP address, it is not possible to assign a host ID with all bits set to 0.
It is not possible to provide a host ID with all bits set to 1, as it is designated as a broadcast address for sending packets to every host on that specific network.

Classless Addressing

The subnetting and supernetting strategies used in classfull addressing did not completely solve the address depletion problem.
As the Internet grew, it became clear that a larger address space was needed as a permanent solution. But larger IP addresses are also required due to the enlarged address space, which means that IP packet syntax must be altered.
Although the long-term solution, known as IPv6, has already been devised, the short-term solution was still produced, using the same address space but changing the allocation of addresses to provide a fair amount to each organization.
The workaround, which uses IPv4 addresses still, is classless addressing. The class privilege was removed from the distribution to compensate for address depletion.
Classless addressing divides the entire address space into chunks of different sizes. The prefix of an address identifies the block (network); the suffix identifies the node (device).
We are capable of having a block of 20, 21, 22 ,..., 232 addresses, theoretically. The requirement that a block of addresses have a power of two addresses is one of the restrictions.
An organization may be assigned one address block. The entire address space is segmented into non-overlapping blocks, as seen in the provided figure.

Classless

Classless addressing permits different prefix lengths than classfull addressing. It is conceivable for prefix lengths to range from 0 to 32.
The prefix's length and network size are inversely correlated. The prefix of a larger network is little, and the prefix of a smaller network is large.
It is important to emphasize that the idea of classless addressing can be applied to classfull addressing with equal ease. Think of a class A address as a classless address with an 8-character prefix length.
Class B addresses with the prefix 16 and higher can be considered classless addresses. Stated differently, classless addressing is a particular kind of classfull addressing.

Difference Between Classful and Classless Addressing

IP addresses are divided into five groups using the classfull addressing approach when they are assigned. In order to prevent the depletion of IP addresses, classless addressing is used. It is a method of IP address allocation that will eventually replace classfull addressing.
A further distinction is the usefulness of classfull and classless addressing. Comparatively speaking, classless addressing is more beneficial and useful than classfull addressing.
In classfull addressing, the network ID and host ID are adjusted according to the classes. However, the distinction between network ID and host ID does not exist with classless addressing. This opens up the possibility of making yet another contrast between both addressing.

CIDR with its notation.

2023-12-02T14:22:00.001+05:30

Understanding CIDR (Classless Inter-Domain Routing or supernetting)

CIDR, also known as Classless Inter-Domain Routing or Supernetting, is a protocol for assigning IP addresses that improves address distribution efficiency and replaces the earlier systems based on Class A, Class B, and Class networks.
Initially, CIDR was designed to slow down the increase in routing tables on routers all over the internet and to slow down the rapid exhaustion of IPv4 addresses.
Consequently, the number of accessible internet addresses has increased significantly।

Slash notation is used to show CIDR addresses, which indicate the number of bits in the network prefix.
For instance, an IP address 192.168.1.0 with 24 prefixes would be written as 192.168.1.0/24. According to this notation, the first 24 bits of an IP address serve as the network prefix, while the remaining 8 bits serve as the host identifier।

Advantages of CIDR.

Effective use of IP addresses: As the pool of accessible IPv4 addresses continues to dwindle, CIDR makes it possible to use IP addresses more effectively.
Flexibility: CIDR makes IP address allocation more flexible, which is beneficial for businesses with intricate network requirements.
Improved routing: CIDR makes it possible for IP traffic to be routed more effectively, which can improve network performance. Decreased administrative overhead: By making IP address and route management simpler, CIDR lowers administrative overhead.

Disadvantages of CIDR.

Complexity: Compared to typical class-based addressing, CIDR implementation and management may be more difficult, requiring specialized knowledge and training.
Compatibility problems: Making the switch to a CIDR-based network may be challenging if some older network equipment is incompatible with CIDR.
Security issues: CIDR may make it more challenging to put security controls like firewall rules and access control lists into place, which may raise security threats.

All things considered, CIDR is a practical and effective way to assign IP addresses and route traffic, albeit not every network or company will find it appropriate. Before installing CIDR, it's critical to assess the benefits and drawbacks of the technology and take your network's unique requirements into account.

Data Communication & Computer Network Assignment No. 2 Session 2023-24.

2023-11-08T13:40:00.003+05:30

DCN- Assignment No. 2

Q1. What is addressing? Explain with its types.

Q2. Write the differences between Logical and Physical addressing.

Q3. What is addressing explain different types of classes in addressing ?

Q4. What do you understand by classfull and classless addressing?

Q5. Write short note on following...

Super-netting.
Sub-netting.
Internetworking.
Masking.
Ethernet.

Q6. Explain IPv4 header with suitable diagram.
Q7. Explain IPv6 header with suitable diagram.

Q8. Write the differences between IPv4 and IPv6.

Q9. Explain the following networking devices with suitable diagram...

Q10. What is NAT? Explain its types.

Q11. What is Ethernet? Explain its types with advantages and disadvantages.

What is Data Communication and its components?

2023-11-04T16:08:00.007+05:30

The only creatures on earth with the ability to interact with one another through language are humans.These days, communication is not limited by time, space, or a person's physical presence since people have developed systems that allow them to share and communicate with their loved ones at any time and from any location. These systems include text, photographs, videos, files, and more.
The process through which many computers exchange information, instructions, and resources is known as communication.
Stated differently, communication can be defined as an act or process that involves sending and receiving data.
An independent group of computers connected to one another is called a network of computers. When a computer is autonomous, it cannot control, restart, or shut down another computer.

Components of Data Communication

Message:-

Information that needs to be communicated from one person to another is called a message. It could be a file with text, music, or video in it.

Sender:-

It is merely a data message-sending device. It could be a workstation, laptop, phone, tablet, or video camera, among other devices.

Receiver:-

A device that receives messages is called a receiver. It could be a workstation, phone, computer, or something else entirely.

Channels of Communication / Transmission Medium:-

The medium that connects two or more workstations is called a communication channel. Workstations can be linked together using wireless or wired media.

A set of guidelines, or protocol:-

Information sent by the sender must also be understood by the recipient in order for it to have any use. Arti, for instance, messages Akhil. It is a pointless discourse if Arti writes in Hindi and Akhil does not comprehend Hindi.

Therefore, there are some set of rules (protocols) that is followed by every computer connected to the internet and they are:

Transfer Control Protocol, or TCP:-

It is in charge of breaking up messages into packets on the source computer and reestablishing the packets after they are received at the receiver or destination computer. Additionally, it verifies that the packets contain information about the message's source, destination, and the order in which it should be reassembled. Finally, it assesses if the message was sent accurately to the intended location.

IP(Internet Protocol):-

Have you ever wondered how a computer determines which packet belongs to which device using IP (Internet Protocol)? What happens if your father receives the message you sent to your friend? Alright, scary. Okay! IP is in charge of managing the target computer's address to ensure that every packet is sent to the right place.

Types of Data Communication

Data transmission and reception between devices is commonly referred to as data communication. There are three categories for data communication:

Simplex communication:-

This type of communication is one-way, or more accurately, unidirectional; it involves devices using their whole transmission capacity while one device only sends and receives data.
IoT, for instance, data entry via a keyboard, music listing via a speaker, etc.

Half-duplex communication:-

This type of communication is two-way, or we may say bidirectional, and both devices can send and receive data, but not simultaneously.
One device can only receive data when it is transmitting it, and vice versa. Consider a walkie-talkie.

Full-duplex communication:-

This type of communication is two-way, or more accurately, bidirectional, allowing data to be sent and received simultaneously between the two devices. For example, landlines, cell phones, etc.

Addressing and its types.

2023-11-04T14:15:00.007+05:30

What is Addressing in Networking?

A computer network is a collection of several linked computers that share one or more resources that are provided on or by network nodes. Rules or network protocols control the sharing and communication between the machines.
A host or computer in a communications network can be uniquely identified by its network address, which might be either logical or physical.
The two separate nodes in the network can communicate with one another because of addressing.
Four different addressing methods are used by the TCP/IP network's communication systems, one for each tier of the protocol architecture.

Addressing in Networking

Types of Addressing in Network

Physical Address
Logical Address
Port Address
Application-Specific Address

Physical Address-

Any network you are on, whether LAN or WAN, gives each node in the network a unique address. This address is also known as a link address and is a physical address.
The physical address is contained in the frames that the data link layer creates from the packets that it receives from the network layer.
The length and format of the address are determined by the type of network utilized.
Unicast, multicast, and broadcast addresses are further classifications for the physical address. The frame that needs to be delivered to a single receiver is given a physical unicast address.
The frame that needs to be transmitted to a collection of receivers includes a physical multicast address.
The frame that needs to be sent to every node or system connected to the network includes the physical broadcast address.

Logical Address-

The scope of logical addressing is wider. It is used to transfer frames across two networks—which could employ different addressing formats—that are separate from one another.
Despite the actual network that supports each node, it is specifically made to identify each one individually.
The IP address assigned to each node connected to the internet is known as its logical address, and no two nodes in this instance may have the same IP address.
Similar to physical addresses, logical addresses are categorized as broadcast (which includes all system nodes), multicast (which includes multiple receivers), and unicast (which includes a single receiver).
Even so, there is a restriction on the number of recipients in broadcasting.

Port Address-

Up till now, we have learned that in order to send and receive data between two nodes in the same or separate network, logical and physical addresses are needed. But things don't stop here. The next step after getting the data at the computer is to determine which computer process needs the data.
Everybody knows that the computer executes several processes simultaneously. Therefore, we must label the process in order to uniquely identify each process in a computer and determine which process the data is for.
A process's address in TCP/IP architecture is referred to as its port address.

Application-Specific Address-

Specific applications can be identified by their application-specific addresses.
For instance, the website address is www.dcandcn.blogspot.com, and the email address is manncsemanjeet@gmail.com.
Thus, these are the four different address types that are utilized with TCP/IP protocols to facilitate network communication.

Difference between Synchronous and Asynchronous Data Transmission

2023-09-23T12:52:00.016+05:30

Synchronous Data Transmission:-

Data is transmitted synchronously in the form of blocks or frames.
Full-duplex communication is being used here. Synchronization between the transmitter and recipient is necessary.
In synchronous transmission, there is no pause between each piece of information.
When transferring a lot of data, synchronous transmission is more dependable and efficient.

Example:

Chat Rooms
Telephonic Conversations
Video Conferencing

Asynchronous Data Transmission:-

Data is transmitted asynchronously in the form of bytes or characters. Half-duplex transmission is the type used in this.
Start bits and stop bits are combined with the data in this transmission. It doesn't need to be synchronized.

Example:

Email
Forums
Letters

Let's see the distinction between synchronous and asynchronous transmission now:

S. No.	Synchronous Transmission	Asynchronous Transmission
1.	In Synchronous transmission, data is sent in form of blocks or frames.	In Asynchronous transmission, data is sent in form of bytes or characters.
2.	Synchronous transmission is fast.	Asynchronous transmission is slow.
3.	Synchronous transmission is costly.	Asynchronous transmission is economical.
4.	In Synchronous transmission, the time interval of transmission is constant.	In Asynchronous transmission, the time interval of transmission is not constant, it is random.
5.	In this transmission, users have to wait till the transmission is complete before getting a response back from the server.	Here, users do not have to wait for the completion of transmission in order to get a response from the server.
6.	In Synchronous transmission, there is no gap present between data.	In Asynchronous transmission, there is a gap present between data.
7.	Efficient use of transmission lines is done in synchronous transmission.	While in Asynchronous transmission, the transmission line remains empty during a gap in character transmission.
8.	The start and stop bits are not used in transmitting data.	The start and stop bits are used in transmitting data that imposes extra overhead.
9.	Synchronous transmission needs precisely synchronized clocks for the information of new bytes.	Asynchronous transmission does not need synchronized clocks as parity bit is used in this transmission for information of new bytes.
10.	Errors are detected and corrected in real time.	Errors are detected and corrected when the data is received.
11.	Low latency due to real-time communication.	High latency due to processing time and waiting for data to become available.
12.	Examples: Telephonic conversations, Video conferencing, Online gaming.	Examples: Email, File transfer,Online forms.

How to Use the Netstat Command and its options?

2022-12-14T15:41:00.013+05:30

Use the Netstat Command and its options

The Command Prompt command known as netstat, or "network statistics," is used to display incredibly precise information about how your computer is interacting with other computers or network devices.

In particular, it may display information on specific network connections, general and protocol-specific networking statistics, and much more, all of which could be used to solve specific networking problems.

Command availability for Netstat

Most versions of Windows, including Windows 11, Windows 10, Windows 8, Windows 7, Windows Vista, Windows XP, Windows Server, and certain earlier Windows versions, have this command available from within the Command Prompt.
Since Netstat is a cross-platform command, it may be used in Linux and macOS as well as other operating systems.

Netstat Command Syntax

netstat [-a] [-b] [-e] [-f] [-n] [-o] [-p protocol] [-r] [-s] [-t] [-x] [-y] [time_interval] [/?]

Netstat Command List
Option	Explanation
netstat	Execute the netstat command alone to show a relatively simple list of all active TCP connections which, for each one, will show the local IP address (your computer), the foreign IP address (the other computer or network device), along with their respective port numbers, as well as the TCP state.
-a	This switch displays active TCP connections, TCP connections with the listening state, as well as UDP ports that are being listened to.
-b	This netstat switch is very similar to the -o switch listed below, but instead of displaying the PID, will display the process's actual file name. Using -b over -o might seem like it's saving you a step or two but using it can sometimes greatly extend the time it takes netstat to fully execute.
-e	Use this switch with the netstat command to show statistics about your network connection. This data includes bytes, unicast packets, non-unicast packets, discards, errors, and unknown protocols received and sent since the connection was established.
-f	The -f switch will force the netstat command to display the Fully Qualified Domain Name (FQDN) for each foreign IP addresses when possible.
-n	Use the -n switch to prevent netstat from attempting to determine host names for foreign IP addresses. Depending on your current network connections, using this switch could considerably reduce the time it takes for netstat to fully execute.
-o	A handy option for many troubleshooting tasks, the -o switch displays the process identifier (PID) associated with each displayed connection. See the example below for more about using netstat -o.
-p	Use the -p switch to show connections or statistics only for a particular protocol. You can not define more than one protocol at once, nor can you execute netstat with -p without defining a protocol.
protocol	When specifying a protocol with the -p option, you can use tcp, udp, tcpv6, or udpv6. If you use -s with -p to view statistics by protocol, you can use icmp, ip, icmpv6, or ipv6 in addition to the first four I mentioned.
-r	Execute netstat with -r to show the IP routing table. This is the same as using the route command to execute route print.
-s	The -s option can be used with the netstat command to show detailed statistics by protocol. You can limit the statistics shown to a particular protocol by using the -soption and specifying that protocol, but be sure to use -s before -p protocol when using the switches together.
-t	Use the -t switch to show the current TCP chimney offload state in place of the typically displayed TCP state.
-x	Use the -x option to show all NetworkDirect listeners, connections, and shared endpoints.
-y	The -y switch can be used to show the TCP connection template for all connection. You cannot use -y with any other netstat option.
time_interval	This is the time, in seconds, that you'd like the netstat command to re-execute automatically, stopping only when you use Ctrl-C to end the loop.
/?	Use the help switch to show details about the netstat command's several options.

Tip:- Use a redirection operator to send what is displayed on the screen to a text file, making it easier to manage all that netstat data in the command line. For further instructions, see How to Redirect Command Output to a File.

Netstat Command Examples

netstat -f

In this first example, we execute netstat to show all active TCP connections. However, we want to see the computers that we're connected to in FQDN format [-f] instead of a simple IP address.

Here's an example of what you might see:

Active Connections
 Proto Local Address Foreign Address State
 TCP 127.0.0.1:5357 VM-Windows-7:49229 TIME_WAIT
 TCP 127.0.0.1:49225 VM-Windows-7:12080 TIME_WAIT
 TCP 192.168.1.14:49194 75.125.212.75:http CLOSE_WAIT
 TCP 192.168.1.14:49196 a795sm.avast.com:http CLOSE_WAIT
 TCP 192.168.1.14:49197 a795sm.avast.com:http CLOSE_WAIT
 TCP 192.168.1.14:49230 TIM-PC:wsd TIME_WAIT
 TCP 192.168.1.14:49231 TIM-PC:icslap ESTABLISHED
 TCP 192.168.1.14:49232 TIM-PC:netbios-ssn TIME_WAIT
 TCP 192.168.1.14:49233 TIM-PC:netbios-ssn TIME_WAIT
 TCP [::1]:2869 VM-Windows-7:49226 ESTABLISHED
 TCP [::1]:49226 VM-Windows-7:icslap ESTABLISHED

Sharing of Hardware resources in the network.

2022-12-14T15:23:00.004+05:30

Setting up a printer on your network involves two steps.

The first step is getting the printer connected to the network, and there are three ways you can do that....

Connect the printer to the network directly.

This is the easiest way to set up a network printer.
It doesn’t require that another PC be turned on to print (like the below methods do), and you don’t have to go through the hassle of setting up sharing.
And, since most printers made within the last few years have networking built in, there’s a good chance your printer supports this option.

Connect the printer to one of your PCs and share it with the network over Home-group.

If connecting a printer directly to the network isn’t an option, you can connect it to a PC on the network and share it with Windows Home group.
It’s easy to set up, and is optimal for networks that are made up of mostly Windows computers. This method, however, requires that the computer its connected to be up and running in order for you to use the printer.

Connect the printer to one of your PCs and share it without Home-group.

This is ideal if your network has other computers running different operating systems, if you want more control over file and printer sharing, or if Home-group just isn’t working very well.
Like the Home-group method, this requires that the computer its connected to be up and running in order for you to use the printer.

Procedure to share hardware resources (printer) over network.

Click on Start in the bottom left corner of your screen. A popup list will appear.
Select Control Panel from the popup list. Type the word network in the search box.
Click on Network and Sharing Center.
Click on Change advanced shared settings, in the left pane.
Click on the down arrow, which will expand the network profile.
Select File and printer sharing and choose Turn on file and printer sharing.
Click on Save changes.

You're now ready to share your printer.

Click on Start in the bottom left corner of your screen. A popup list will appear.
Click on Devices and Printers, from the popup list.
Right click the printer you want to share. A drop down list will appear.
Select Printer properties from the drop down list.
Click on the Sharing tab
Select the Share this printer check box.

In order for other people to connect to the printer, they just have to add the network printer that you just opened for sharing to their computers. Here's how to do this.

Click on Start in the bottom left corner of your screen. A popup list will appear.
Click on Devices and Printers from the popup list.
Select Add a printer.
Click on Add a network, wireless or Bluetooth printer.
Click the shared printer.
Click Next. Continue according to the instructions on the screen

Managing user accounts in windows and LINUX.

2022-12-14T15:16:00.004+05:30

Manage User Accounts in Windows 10

In summary, to manage a user account in Windows 10, do the following:

In the Settings window, click Accounts, and then click Family & other users.
Click the account you want to modify, to display your options. Then click Change account type. Click to view a larger image. Any account can be an Administrator account.
In the Account type list, click Administrator. Then click OK.

How to create a new local user in Windows 10

Creating a new user account is easy using Windows 10’s Settings application. You may also create a Microsoft account to be able to transfer accounts and files between computers.

Your taskbar's Start menu should now be selected. The Windows 10 logo can be seen on this icon. We suggest reading the Get Started with Windows 10 page on our website if you are unfamiliar with the Windows 10 user interface.
Select the gear-shaped Settings icon. As an alternative, you can access this application faster by pressing Windows + I on your keyboard.

Click on the Accounts tile.

Switch to the Family & other users category using the panel on the left side of the screen. You should see a list of all the current users on your computer.
Click on the Add someone else to the PC button.

To add a new local user, select the I don't have this person's sign-in information option.

Click on the Add a user without a Microsoft account option.

Enter the desired username. If needed, you can also include a password and a password hint. This will give extra privacy to the user of the account. In the future, you’re always able to change all of this information.

How to customize a local user on Windows 10?

Click on the Start menu in your taskbar.

You’ll see your current user picture on the left side of the panel. Click on it and select Change account settings from the context menu.

Here, you can modify your profile picture or take a new one using your camera, and manage your local account.
If you have a Microsoft account connected, click on the Manage my Microsoft account link to be able to modify settings such as password and security.

Identify the IP address of a workstation and the class of the address and configure the IP Address on a workstation.

2022-12-14T12:27:00.005+05:30

Setting the IP address in Windows XP and Windows 2000

To set the IP address within Windows XP and Windows 2000, complete these steps.

Click Start >Settings >Control Panel.
On the control panel, double-click Network Connections.
Right-click Local Area Connection.
Click Properties.

Attention: Before making any changes, make a note of the settings as they are. If you disconnect the PC or mobile device after configuring the ASMI Web interface, you will be able to recover these settings thanks to this.

Note: If Internet Protocol (TCP/IP) does not appear in the list, do the following:

Click Install.
Select Protocol, and then click Add.
Select Internet Protocol (TCP/IP).
Click OK to return to the Local Area Connection Properties window.
Select Internet Protocol (TCP/IP), and then click Properties.
Select Use the Following IP Address.
Complete the IP address, Subnet mask, and Default gateway fields by using the values in step 4 from Accessing the ASMI using a Web Browser.
Click OK on the Local Area Connection Properties window. It is not necessary to restart your PC.

Open Windows Settings by going to Start → Settings or typing settings into the Start Menu.
In the Windows Settings window, click Network & Internet.

In the Network & Internet pane, under Status, click View your network properties.

Your IP Address will be shown under IPv4 Address in the Properties window.

Setting the IP address in Linux

To set the IP address in Linux, complete these steps. You will need the information from step 4 in Accessing the ASMI using a Web Browser to complete step 4 in the following procedure.

Make sure you are logged on as a root user.
Start a terminal session.
Type ifconfig at the command prompt.

Attention: Before making any changes, note or print the current settings. If you disconnect the PC or mobile computer after configuring the ASMI Web interface, you can use this to recover these settings.

Type ifconfig eth0 xxx.xxx.xxx.xxx netmask xxx.xxx.xxx.xxx, where the xxx.xxx.xxx.xxx values are the values from step 4 for IP address and Subnet mask.
Press Enter.

What is SSL?

2022-12-06T15:19:00.003+05:30

What is SSL?

A security mechanism for the Internet based on encryption is known as SSL, or Secure Sockets Layer.
To provide privacy, authentication, and data integrity in Internet communications, Netscape created it for the first time in 1995. The present TLS encryption now in use predates SSL.
The URL of a website that uses SSL/TLS begins with "HTTPS" rather than "HTTP."

SSL/TLS

How does SSL/TLS work?

SSL encrypts data that is sent across the web in order to offer a high level of privacy. As a result, anyone attempting to intercept this data will only be able to make out a jumbled collection of characters that is incredibly difficult to decrypt.
In order to make sure that both communicating devices are indeed who they say they are, SSL starts an authentication procedure between them known as a handshake.
In order to provide data integrity and ensure that the data has not been tampered with before reaching its intended receiver, SSL additionally digitally signs data.
Each new version of SSL is more secure than the previous one. TLS was modified from SSL in 1999.

Why is SSL/TLS important?

Data on the Web used to be sent in plaintext, which meant that anyone could read it if they intercepted the communication. For instance, if a customer went to a shopping website, made a purchase, and entered their credit card information, that information would be transmitted across the Internet in clear view.
SSL was developed to address this issue and safeguard user privacy. SSL makes sure that anyone who intercepts the data can only see a jumbled mess of characters by encrypting any data that travels between a user and a web server.
The credit card number submitted by the customer is now secure and only accessible by the purchasing website.
SSL also prevents specific cyber-attacks: It verifies web servers, which is crucial because hackers frequently attempt to create phony websites in order to deceive consumers and steal data. Like a tamper-proof seal on a medication container, it likewise prevents attackers from altering data while it is being transmitted.

What is an SSL certificate?

Only websites that have an SSL certificate can use SSL (technically a "TLS certificate"). An SSL certificate serves as a badge or identification card that verifies a person is who they claim to be. The server hosting a website or application stores and displays SSL certificates on the Internet.
The website's public key is one of the most crucial pieces of data in an SSL certificate. Encryption and authentication are made feasible via the public key.
The public key is viewed by a user's device, which uses it to create safe encryption keys with the web server. The web server also has a private key, which is kept private, that it uses to decrypt data that has been encrypted using the public key.
SSL certificates are issued by certificate authorities (CA).

What are the types of SSL certificates?

The varieties of SSL certificates are numerous. Depending on the kind, a single certificate may be used for one or several websites:

Single-domain: Only one domain is covered by a single-domain SSL certificate (a "domain" is the name of a website, like www.dcandcn.blogspot.com).
Wildcard: A wildcard SSL certificate only applies to one domain, just like a single-domain certificate does. But it also includes the subdomains of that site. A single-domain certificate could only protect the first domain, whereas a wildcard certificate could protect www.dcandcn.blogspot.com, www.mskuthar.blogspot.com, and b2adigitals.blogspot.com.
Multi-domain: Multi-domain SSL certificates, as their name suggests, can be used with numerous unrelated domains.

Different levels of validation are available for SSL certificates as well. Similar to a background check, the level of validation varies according to how thorough the check is.

Domain Validation: This is the simplest and least expensive level of validation. A company only needs to demonstrate that they have domain control.
Organization Validation: The CA contacts the person or company directly in this process, which is more hands-on. For users, these certifications are more reliable.
Extended Validation: Before an SSL certificate can be issued, an organisation must undergo a thorough background investigation.

What is Kerberos? How Does Kerberos Work?

2022-12-06T14:52:00.006+05:30

Kerberos and its Work

Across an untrusted network, such as the internet, Kerberos, a computer network security protocol, authenticates service requests between two or more trusted hosts.
It authenticates client-server applications and confirms users' identities using secret-key cryptography and a reliable third party.

The Massachusetts Institute of Solution (MIT) first created Kerberos for Project Athena in the late 1980s. Kerberos is currently Microsoft Windows' standard authorization technology.
Additionally, there are Kerberos implementations for other operating systems such Apple OS, FreeBSD, UNIX, and Linux.
The three-headed dog Kerberos, sometimes known as Cerberus, who served as the canine gatekeeper of the underworld's entrance in Greek mythology, is the source of the protocol's name.
Despite one notable exception, Kerberos was a fairly helpful guardian despite having a snake tail and an especially terrible temper.
However, in the context of the protocol, the three Kerberos heads stand in for the client, the server, and the Key Distribution Center (KDC). As a trusted third-party authentication service, the latter performs its duties.

What is Kerberos Used For?

Although Kerberos is used extensively on security systems that require dependable auditing and authentication functions, it is present everywhere in the digital world.
Active Directory, NFS, Samba, and Posix authentication all require Kerberos. It also serves as an alternative to SMTP, POP, and SSH for authentication.

What Does Kerberos Authentication Protocol Do?

This protocol was produced by MIT for the Athena project. The three-headed dog of Hades, who defended hell in Greek mythology, gave it its name.
The Kerberos protocol stands for the following three things, which is why they chose this name:

Client.
Network Resource (Application server).
Key Distribution Center (KDC).

Kerberos Authentication's Advantages

There are many benefits to using Kerberos in any cyber-security setting. The benefits of it include:

Effective Access Control: Kerberos provides users with a central location to monitor logins and the application of security policies.
Key Tickets Have a Limited Lifetime: Each Kerberos ticket has a timestamp, lifetime information, and an administrator-controlled authentication period.
Mutual Authentication: Users and service systems can verify each other's identities.
Reusable Authentication: Each user only needs to be confirmed by the system once thanks to the reusable and long-lasting nature of Kerberos user authentication. The user won't have to continue entering their personal information for authentication as long as the ticket is in effect.
Strong and Diverse Security Measures: The strong and secure Kerberos security authentication protocols use encryption, numerous secret keys, and third-party authorization. All secret keys are encrypted, and passwords are not transferred across networks.

Overview of the Kerberos Protocol

Here is a more thorough explanation of Kerberos authentication. By dissecting it into its constituent parts, we can also learn more about how it functions.
The key players in the usual Kerberos procedure are listed below:

Client: The client communicates and acts on behalf of the user while making a service request.
Server: The server is where the user wants to access the service.
Server for authentication (AS): The desired client authentication is carried out via the AS. The AS issues the client a TGT ticket if the authentication is successful. The other servers are reassured by this ticket that the client is authenticated.
Key Distribution Center (KDC): A database (db), the authentication server (AS), and the ticket granting server (KDC) are conceptually split into three sections of the authentication server in a Kerberos context (TGS).
Ticket Granting Server (TGS): It is a single server that houses these three components in turn: As a service, the TGS is an application server that generates service tickets.

Data Communication and Computer Network Assignment No. 2

2022-12-05T16:02:00.009+05:30

Data Communication & Computer Network

Assignment No. 2 (2022-2023)

1. Write the differences between Logical and Physical addressing.

2. What is addressing explain different types of classes in addressing ?
3. Write short note on following...
Super-netting.
Sub-netting.
Internetworking.
Masking.
Ethernet.
4. Explain IPv4 with suitable diagram.
5. Explain IPv6 with suitable diagram.
6. Write the differences between IPv4 and IPv6.
7. Explain the following networking devices with suitable diagram...
NIC.
Hub.
Switch.
Router.
Repeater.
Modem.
Gateway.
8. What is Firewall? Explain its types with suitable diagram.
9. What are the principles of network security? Explain.
10. What is Cryptography? Explain Symmetric and Asymmetric Key
cryptography with suitable diagram.
12. What are the network security protocols? Explain.
13. Explain the following Network troubleshooting tools.
PING.
IPCONFIG.
IFCONFIG.
NETSTATE.
TRACEROOT.
Wireshark.
Nmap.
TCPDUMP.
ROUTEPRINT.
Kerberos.
14. Explain DHCP server with its advantages and disadvantages.

Install and configure a network interface card in a workstation.

2022-12-02T15:12:00.004+05:30

Install and configure a network interface card in Window

Open the Control Panel.
Set View by to Category.
Click Network and Internet.
Click Network and Sharing Center.
On the left pane, click Change adapter settings.
Right-click the local area network connection that is connected to the radio hardware and select Properties.
If an unused network connection is available, the local area connection appears as Unidentified network.
If you plan to reuse your network connection, select the local area connection that you plan to use for the radio hardware.
If you have only one network connection, check if you can connect wirelessly to the existing local area network. If you can, you can use the network connection for the radio hardware.
You can use a pluggable USB to Gigabit Ethernet LAN adapter instead of a NIC. The instructions are the same.
On the Networking tab of the Properties dialog box, clear all options except Internet Protocol Version 4 (TCP/IPv4). Other services, particularly antiviral software, can cause intermittent connection problems with the radio hardware.
Double-click Internet Protocol Version 4 (TCP/IPv4).
On the General tab, select Use the following IP Address.
The default IP address of the Xilinx Zynq hardware board is 192.168.1.101. The development computer network connection must be on the same subnet as the hardware board. To meet this requirement, a compatible IP address must be assigned to the development computer network connection. Set the network IP address to 192.168.1.x, where x is any number in the range 1 through 255, apart from 101.
Leave the subnet mask set to the default value of 255.255.255.0 and click OK.

Making of cross cable and straight cable.

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UTP cabling

Eight wires make up a UTP cable. Four pairs of wires make up this collection.
There are two twisted wires in each pair.
The first wire has a single plastic coating with a colour code, but the second wire has same colour plus a white colour striped coating.
For the brown wire pair, for instance, one wire has a coating that is entirely brown, while the other wire has a coating that is striped with brown and white.
A UTP cable is shown in the figure below.

Exactly why are the cables twisted?

Electromagnetic interference results from the passage of electrical current through copper wires (EMI). The electrical signals travelling via nearby wires, including those that are a part of the same cable, are hampered by EMI.
It is referred to as the cross talk. Cross talk is eliminated by twisting the wires in pairs.

RJ-45 (UTP cable) connector

Both the switch port and the NIC include an eight-pin RJ-45 (UTP cable) slot.
The RJ-45 connection is utilized to link these pins to the wires of a UTP cable.
The RJ-45 connector has eight physical locations, known as pin positions or simply pins, into which the eight wires of the UTP cable can be inserted.
These pins make it possible for the ends of copper wires to make contact with NIC or switch port pins.

An RJ-45 connector is shown in the picture below.

Constructing a UTP cable:-

Pins 1 and 2 are used by a NIC to send data. Using pins 3 and 6, it receives data. A switch makes it do the reverse.
Data is transmitted from pins 3 and 6 while being received on pins 1 and 2.
A UTP cable can be created in two different methods depending on the type of end devices.
The first kind of connection, referred to as a straight-through cable, links two various end devices, such as a PC and a switch.
The second kind of cable, called a cross-over cable, links two identical end devices, like a PC and a PC or a Switch and a Switch.
Let's examine both forms of cable's construction in more depth.

Ethernet Straight-through cable

The conductors in this cable are positioned the same way at both ends.
The cable's pin 1 at one end is connected to pin 1 at the other end by a wire.
Pin 2 on one end of the cable is connected to pin 2 on the other end, and so on.
The wire positions for the straight-through cable on both sides are listed in the following table.

Side A	Side B
Green White	Green White
Green	Green
Orange White	Orange White
Blue	Blue
Blue White	Blue White
Orange	Orange
Brown White	Brown White
Brown	Brown

A straight-through cable is used to connect the following devices.

PC to Switch
PC to Hub
Router to Switch
Switch to Server
Hub to Server

Ethernet cross-over cable

The receiving pins on one side of this cable are connected to the sending pins on the other.
The cable's pin 1 on one end and pin 3 on the other end are connected by a wire. On the opposite end of the cable, pin 6 is connected to the wire at pin 2. The remaining wires join at both ends in the identical locations.
The cross-over cable's wire placements on each side are listed in the following table.

Side A	Side B
Green White	Orange White
Green	Orange
Orange White	Green White
Blue	Blue
Blue White	Blue White
Orange	Green
Brown White	Brown White
Brown	Brown

The cross-over cable is used to connect the following devices.

Two computers
Two hubs
A hub to a switch
A cable modem to a router
Two router interfaces

Recognition and use of various types of connectors RJ-45, RJ-11, BNC, and SCST.

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Connectors

A device that eliminates a section of cabling or implements a state of access for network devices, including PCs, hubs, and switches. Connectors can be famous for their physical presentation and mating features, including jacks and attachments (male connectors) or attachments and ports (female connectors).
Connectors are used to connect the guided (wired) transmission media to devices like the hub, server, workstations etc.

RJ45 Connector:-

RJ45 is newer, modular, self-securing and compact technology used for connecting the Ethernet cables to different electronic devices.
The RJ45 is an 8 pin connector used to attach the Ethernet interfaces. It is known as an 8P8C connector.

Types of cables based on the termination:

Straight-over-cable
Crossover cable

RJ11 Connector:-

RJ11 is used to terminate the conventional PSTN telephone networks. RJ11 is a four pins connector which is used for terminating the telephone wires.
The RJ11 technically uses the center 2 contacts of 6 available and is used for wiring a single phone line.
It is the common connector for plugging a telephone into the wall and the handset into the telephone.

BNC Connector:-

Virtually any standard connector is able to carry current over a mechanical connection for DC and low-frequency AC circuits.
Radio frequency, on the other hand, requires a connection that will minimize changes in impedance, which could generate reflection and standing waves that can cause damage.
Coaxial cables can carry radio frequencies while maintaining a characteristic impedance.
BNCs are constant impedance connectors they have the same characteristic impedance across the whole connection, equal to that of coaxial cables.
This makes BNC connectors well-suited for RF applications, as RF signals traveling along a coax cable will not see any impedance changes as they pass through the BNC connector, resulting in fewer reflections and a lower level of loss.

SC-ST Connectors:-

SC stands for subscriber connector and is a standard-duplex fiber-optic connector with a square molded plastic body and push-pull locking features. SC connectors are typically used in data communication, CATV, and telephony environments.
ST stands for straight tip, a high-performance fiber-optic connector with round ceramic ferrules and bayonet locking features. ST connectors are more common than SC connectors.
You can generally use SC and ST connectors with either single-mode or multi-mode fiber-optic cabling.
Coupling receptacles for these connectors come in either panel-mount or free-handing designs. For narrow space installations, you can get 90-degree boot versions instead of straight versions.
SC and ST connectors come in both simplex and duplex form.

Data Communication and Computer Networks – Notes & Tutorials

Assignments

Routing principles/Issues.

2. How Does Routing Work?

Example Routing Table

3. Routing Principles

3.1 Correctness

3.2 Simplicity

3.3 Robustness

3.4 Stability

3.5 Fairness

3.6 Optimality

4. Routing Metrics

1. Hop Count

2. Bandwidth

3. Delay

4. Cost

5. Reliability

6. Load

5. Routing Issues

5.1 Path Selection

5.2 Routing Table Management

5.3 Routing Loops

5.4 Congestion

5.5 Network Failure

5.6 Scalability

5.7 Routing Overhead

5.8 Security

6. Static and Dynamic Routing

Examples of Dynamic Routing Protocols

7. Complete Routing Process

8. Important Points for BTEUP Exam

Routing Principles

Routing Issues

Exam Definition

Network Layer – Design Issues

Basic Network Layer Diagram

What are Network Layer Design Issues?

1. Store-and-Forward Packet Switching

Diagram

2. Services Provided to the Transport Layer

Connectionless Service

Connection-Oriented Service

3. Routing

Example

4. Congestion Control

Diagram

5. Quality of Service (QoS)

6. Internetworking

7. Fragmentation and Reassembly

IPv4

IPv6IPv6 routers do not fragment packets. If fragmentation is required, it is performed by the source using the appropriate IPv6 fragmentation mechanism.

8. Connectionless vs Connection-Oriented Service

9. Important Network Layer Design Issues

Short Exam Definition

Key Point

IPv6 (Internet Protocol Version 6)

IPv6 (Internet Protocol Version 6)

1. Introduction to IPv6

Basic Diagram

2. IPv6 Address

IPv6 Address Structure

Example

3. IPv6 Address Shortening

Rule 1: Leading zeros can be removed

Rule 2: Consecutive zero groups can be replaced by ::

4. IPv6 Address Structure

5. Types of IPv6 Addresses

A. Unicast

B. Multicast

C. Anycast

6. IPv6 Does Not Use Broadcast

7. IPv6 Packet Format

8. IPv6 Header

Important Fields

9. IPv6 Communication

10. IPv6 Auto-Configuration

11. Neighbor Discovery Protocol (NDP)

12. Advantages of IPv6

1. Huge Address Space

IPv6
IPv6 routers do not fragment packets. If fragmentation is required, it is performed by the source using the appropriate IPv6 fragmentation mechanism.

Rule 2: Consecutive zero groups can be replaced by `::`