Class B

Definition

Class B refers to a range of IP addresses that are designated for medium-sized networks, capable of accommodating up to 65,534 hosts. This class uses a subnet mask of 255.255.0.0, which allows for a significant number of addresses in the network while maintaining efficient routing. Understanding Class B is crucial in managing IP addressing and subnetting as it helps network administrators allocate resources effectively and avoid IP conflicts.

5 Must Know Facts For Your Next Test

1. Class B IP addresses range from 128.0.0.0 to 191.255.255.255, which encompasses over 16,000 individual networks.
2. Class B networks typically use a default subnet mask of 255.255.0.0, providing 16 bits for the network portion and 16 bits for host addresses.
3. Each Class B network can support up to 65,534 devices, making it suitable for large organizations and universities.
4. The first two bits of a Class B address are always '10', helping routers determine the class when processing the address.
5. Class B is less commonly used than Class C in smaller networks, but its ability to support larger numbers of hosts makes it essential for expansive network designs.

Review Questions

• How does the subnet mask for Class B affect the allocation of IP addresses within a network?
  • The subnet mask for Class B, which is 255.255.0.0, divides the IP address into a network portion and a host portion. This configuration allows for 16 bits dedicated to hosts, meaning each Class B network can accommodate up to 65,534 devices. By having a larger range of available addresses compared to smaller classes, Class B facilitates the needs of medium-sized organizations by providing ample room for device growth while simplifying network management.
• Discuss the differences between Class B and Class C IP addressing in terms of network size and structure.
  • Class B and Class C differ significantly in their capacity and intended use. Class B supports larger networks with up to 65,534 hosts due to its default subnet mask of 255.255.0.0, making it suitable for medium to large organizations. In contrast, Class C addresses have a maximum host capacity of 254 devices with a subnet mask of 255.255.255.0, which is ideal for small networks or individual departments within an organization. Understanding these differences is crucial when designing network infrastructure.
• Evaluate the impact of classful addressing on modern networking practices and the relevance of Class B in today’s context.
  • Classful addressing has largely been replaced by Classless Inter-Domain Routing (CIDR) due to the inefficiency in IP address allocation and routing table sizes it imposed on modern networks. However, understanding Class B remains relevant as it provides historical context and insight into how IP addressing evolved. While CIDR allows for more flexible allocation and better utilization of IP addresses, knowledge of Class B helps network professionals appreciate how network sizes were originally structured and the importance of accommodating larger groups of devices efficiently.

Related terms

IP Address: A numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication.

Subnet Mask: A 32-bit number that divides an IP address into a network and host portion, determining how many bits are allocated for each.

Classful Addressing: An early method of allocating IP addresses based on fixed classes (A, B, C, etc.), which defined the range of possible networks and hosts.