Identify Which Of The IP Addresses Below Belong To A Class- A Network? A. \( 126.57 .135 .2 \) B. 11010111001010111111111101010000
Understanding IP addressing is fundamental for network management, cybersecurity, and internet connectivity. When working with IP addresses, one common task is to determine the class of a given address, which influences how networks are segmented and how routing is handled. In this article, we will analyze two IP addresses—one in decimal notation and the other in binary—and identify which of these belongs to a Class-A network. This comprehensive guide aims to clarify the criteria used to classify IP addresses, provide step-by-step analysis, and enhance your network knowledge.
What Are IP Address Classes?
Before diving into the specific addresses, it’s essential to understand the concept of IP address classes. IPv4 addresses are divided into several classes based on their initial bits and range, primarily to facilitate efficient routing and address allocation.
Overview of IPv4 Classes
| Class | Address Range (Decimal) | Leading Bits | Typical Use Cases |
|--------|---------------------------|----------------|---------------------------------------------------|
| Class A | 0.0.0.0 to 127.255.255.255 | 0 | Large networks, multinational organizations |
| Class B | 128.0.0.0 to 191.255.255.255 | 10 | Medium-sized networks |
| Class C | 192.0.0.0 to 223.255.255.255 | 110 | Small networks, personal and small business networks |
| Class D | 224.0.0.0 to 239.255.255.255 | 1110 | Multicast addresses |
| Class E | 240.0.0.0 to 255.255.255.255 | 1111 | Experimental, reserved for future use |
Note: The range 0.0.0.0/8 is reserved for special purposes, and 127.0.0.0/8 is used for loopback addresses.
Analyzing the Given IP Addresses
Let's evaluate each provided address to determine if it belongs to a Class-A network.
Address A: 126.57.135.2
Step 1: Convert the Address to Decimal Range
This address is already in standard dotted decimal notation, so we analyze the first octet (126).
Step 2: Determine the Class Based on the First Octet
- The first octet is 126.
- Class A addresses range from 0 to 127.
- Therefore, 126 falls within the Class A range.
Step 3: Confirm the Address Range
- Since 126 is within 0-127, Address A is a Class-A address.
- Also, 126 is not reserved for special purposes like 127 (loopback), so it is a valid Class-A address.
Conclusion: Address A (126.57.135.2) belongs to a Class-A network.
Address B: 11010111001010111111111101010000
Step 1: Recognize the Address Format
This is a binary string of 32 bits:
11010111 00101011 11111111 01010000
Let's split it into four octets:
- First Octet: 11010111
- Second Octet: 00101011
- Third Octet: 11111111
- Fourth Octet: 01010000
Step 2: Convert the First Octet to Decimal
Convert 11010111 to decimal:
- 1 2^7 = 128
- 1 2^6 = 64
- 0 2^5 = 0
- 1 2^4 = 16
- 0 2^3 = 0
- 1 2^2 = 4
- 1 2^1 = 2
- 1 2^0 = 1
Sum:
128 + 64 + 0 + 16 + 0 + 4 + 2 + 1 = 215
Step 3: Determine the Class Based on the First Octet
- First octet in decimal: 215
- Class A addresses: 0–127 (first octet)
- Class B addresses: 128–191
- Class C addresses: 192–223
Since 215 > 223, it falls into the Class D range.
Step 4: Confirm the Address Class
- 215 is within 224–239, which is the Class D multicast address range.
- Therefore, this address belongs to a multicast address, not a Class A network.
Conclusion: Address B (binary: 11010111 00101011 11111111 01010000) does not belong to a Class-A network; it is a Class D multicast address.
Summary of Analysis
| Address | Format | First Octet | Address Class | Belongs to Class-A? |
|---------|---------|--------------|----------------|---------------------|
| A | Decimal | 126 | Class A | Yes |
| B | Binary | 215 | Class D | No |
Why Is Class Identification Important?
Class identification impacts network design, routing, and IP address allocation. For example:
- Class-A addresses are used for very large networks, with a small number of network identifiers but many host addresses.
- Class B addresses serve medium-sized networks.
- Class C addresses are suitable for small networks, such as small businesses or home networks.
- Class D addresses are reserved for multicast groups, not typical network routing.
Knowing the class helps administrators efficiently allocate IP addresses, design subnets, and troubleshoot network issues.
Additional Considerations
- Reserved Addresses: Some addresses within each class are reserved for special purposes (e.g., loopback, broadcast).
- CIDR Notation: Modern networks often use Classless Inter-Domain Routing (CIDR), which bypasses the traditional class system, but understanding the original class system remains valuable.
Conclusion
Based on the detailed analysis:
- The IP address 126.57.135.2 is a Class-A address because its first octet (126) falls within the range 0–127.
- The binary address 11010111001010111111111101010000 corresponds to an address in the 215 range, which is Class D, used for multicast purposes.
Therefore, the only address from the options that belongs to a Class-A network is:
A. 126.57.135.2
Understanding how to classify IP addresses is vital for network configuration, security, and efficient management. Whether you're a network administrator, cybersecurity professional, or IT student, mastering these fundamentals enhances your ability to design and troubleshoot modern networks effectively.
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