CCNA Class 04: Work Functionality of the required Network Components & Number System

In computer networking, collision domains, and broadcast domains are key concepts that define how devices interact within a network. They play an essential role in managing data flow, traffic segmentation, and network performance.

Collision Domain

A collision domain is a part of a network where packet collisions can happen when two or more devices try to send data simultaneously on a shared medium. Collisions occur because devices compete for the same bandwidth in this segment, which can slow down data transfer and require packets to be resent.

Characteristics:

1. Common in traditional Ethernet networks using hubs, which do not segment traffic.

2. Every device in a collision domain shares the same communication channel.

3. Collisions are detected and managed by Carrier Sense Multiple Access with Collision Detection (CSMA/CD) in Ethernet networks.

4. Switches break up collision domains by creating a separate collision domain for each port, isolating devices and reducing the chance of collisions.

Impact: In networks with a single, large collision domain (like those with hubs), collisions become more frequent, leading to network inefficiency. Switches reduce collision domains significantly, creating more efficient network segments.

Example:

A hub with four connected devices has one large collision domain, so any device sending data at the same time as another will cause a collision. In a switch, each port forms its collision domain. So, if four devices are connected to a switch, each device operates in an independent collision domain.

Broadcast Domain

A broadcast domain is a part of a network where broadcast frames sent by one device are received by all other devices in the same domain. Broadcasts are typically used for functions like address resolution, where a device needs to identify the MAC address of another device on the same network.

Characteristics:

1. All devices connected through a switch or hub are in the same broadcast domain since they receive all broadcast messages.

2. Routers, however, create separate broadcast domains for each interface, preventing broadcasts from crossing between networks.

3. Broadcast domains are essential for communication within a local network but can cause congestion if too many broadcasts are present, especially in large networks.

   
   
   

Impact: A large broadcast domain can generate excessive broadcast traffic, which consumes bandwidth and processing power on each device, reducing network efficiency. Routers or VLANs (Virtual LANs) are typically used to limit broadcast domains by creating isolated segments.

Example:

In a local network with a switch, all connected devices are in the same broadcast domain. A broadcast message sent by one device is forwarded to all other devices by the switch.

A router separates broadcast domains, so a device in one segment won’t receive broadcasts from another segment.

How to calculate the Collision Domain and Broadcast Domain

As we Know, Some of the Computer networking devices are -

1. Hub - Single collision domain and single broadcast domain.
2. Switch - Multiple collision domain and Single broadcast domain.
3. Router - multiple collision and multiple broadcast domain.
4. Bridges - A bridge breaks collision domains into two, but it doesn't segment broadcast domains.

For Example by the figure, 

Fig: For Collision Domain Calculation, Six Collision Domains

Fig: For Broadcast Domain Calculation, Three Broadcast Domains

Digital Number System in Computer Science -

In digital computing, number systems represent and process data. Digital systems typically use binary, but other number systems like decimal, octal, and hexadecimal also play roles. Here’s a breakdown of these systems and their classifications are -

1. Binary (Base-2)

1. Digits: 0, 1

2. Use: Binary is the fundamental number system in digital computing since computers operate using bits (binary digits).

3. Example: (1101)2

2. Decimal (Base 10)

1. Digits: 0 to 9

2. Use: This is the standard number system for human-readable information.

3. Example: (13)10

3. Octal (Base 8)

1. Digits: 0 to 7

2. Use: Occasionally used in computing as a shorthand for binary; it groups binary digits in sets of three

3. Example: (15)8, (Which is equivalent to 11012 in Binary)

4. Hexa-Decimal (Base 16)

1. Digits: 0 to 9 and A=10 to F=15

2. Use: Widely used in computing for memory addresses, colors in graphics, and as a compact representation of binary data (groups binary digits in sets of four).

3. Example: D16, (Which is equivalent to 11012 in Binary and 1310 in Decimal.)

• Binary to Decimal Conversion

Example 01: let's convert the binary number 11112 to decimal:

• Decimal to Binary Conversion

To convert a decimal number to a binary number, we need to follow these steps:

1. Divide the decimal number by 2 and get the quotient and the remainder.

2. Write down the remainder as the rightmost bit of the binary number.

3. Repeat the process with the quotient until it becomes zero.

4. Write down the final quotient as the leftmost bit of the binary number.

5. Read the binary number from left to right.

Let’s see an example:

Convert the decimal number (87)10 =(?)2 to a binary number.

Solution: 

• How to Convert Decimal Fractions to Binary Fractions?

To convert a decimal fraction to a binary fraction, we need to follow these steps:

1. Multiply the decimal fraction by 2 and get the integer part and the fractional part.

2. Write down the integer part as the leftmost bit of the binary fraction.

3. Repeat the process with the fractional part until it becomes zero or repeats.

4. Write down the final integer part as the rightmost bit of the binary fraction.

5. Read the binary fraction from left to right.

Let’s see an example: Convert the decimal fraction (0.95)10 to a binary fraction.

• How to Convert Binary Fractions to Decimal Fractions?

For example,

# Binary to Octal Conversion

Group binary digits in sets of 3 from right to left (add leading zeros if necessary). Each group represents an octal digit. In binary system bits represent, 111101101

In octal number system 3 bits from right to left is, 111 101 101

Example 01: Convert (101110)₂  to Octal

    1. Group as 000101110 (add leading Zeros if necessary): 000 101 110

    2. Convert Group as,  000 = 0*2^2+0*2^1+0*2^0 = 0

                                    101 = 1*2^2+0*2^1+1*2^0 = 5

                                    110 = 1*2^2+1*2^1+0*2^0 = 6

    3. Conversion is, (101110)₂ = (056)₈    

_{# Decimal to Octal Conversion}

_{To convert from decimal to octal, start dividing decimal number by 8, and whatever the reminder getting, writing down from bottom to top.}

_{Example 01: Convert (10.25)10  to (?)8}

    1.    Divide by 8 to the Decimal number and reminder will be bottom from the top.

    2. So, the Conversion is, (10)10  =    (12)8

Fraction Calculation, 0.25 * 8 = 2.

So, Total Conversion of Decimal to Octal number system is, (10.25)10 = (12.2)8 

_{*****Do the Practice Octal to Decimal and Octal to Binary*****}

# Hexadecimal to Binary Number System

    1. Convert each hexadecimal digit to its 4-bit binary equivalent

    

    2. Example: Convert  (3A)16 to binary.

                      First bit, 3 = 0011

                      Second bit, A = 1010

       So, the conversion of (3A)16 is (00111010)2

***Do the Practice Binary to Hexadecimal Number System Conversion***

# Hexadecimal to Decimal Conversion

    1.    Each hexadecimal digit represents a power of 16, starting from the rightmost digit.

   2. Example: Convert 6CF (hex) to Decimal

    Let, 6 = 6

           C = 12

           F = 15

    Start at the unit’s place of the number and multiply each digit by a       power of 16 in order to convert this to a decimal number system.

    

    6CF = (6 × 16^2) + (12 × 16^1) + (15 × 16^0)

            =  1536 + 192 + 15

            =  (1743)10

So, Decimal value of (6CF)16 is (1743)10.

**** Do Practice Decimal to Hexadecimal Conversion****

# Hexadecimal to Binary Conversion

    1.    Convert each hexadecimal digit to its 4-bit binary equivalent.

    2.      Example: Convert the Hexadecimal of (A2F7)16 = (?)2

Method-1: Indirect Method (First, Hexadecimal to Decimal, finally, Decimal to binary)

    

    Hexadecimal to Decimal: A = 10

                                             2 = 2

                                             F = 15

                                             7 = 7

    So, The Hexadecimal to Decimal Conversion is, 10*16^3 + 2 * 16^2 + 15 * 16^1 + 7 * 16^0 = 41,719

    Decimal to Binary: (41719)10 = (1010001011110111)2

   

Finally, The Hexadecimal to Binary Conversion is,

                                                (A2F7)16 = (1010001011110111)2

    

Method 2: Direct Method: Hexadecimal to Binary Using Grouping

Example: Convert (6A)16 = (1101010)2

                        Let, 6 = 0110

                                = 1010

    

Thus, The Hexadecimal to Binary Conversion is, (6A)16 = ( 01101010)2

**** Do Practice Binary to Hexadecimal Conversion****