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(also subnet addressing, subnet partitioning)

Subnetting definition

Subnetting is a technique in computer networking that divides a single IP network into multiple smaller subnetworks, known as subnets. It involves borrowing bits from the host portion of an IP address to create a subnet identifier, allowing for more efficient use of IP addresses and improved network management.

See also: supernetting, routing table

Subnetting use cases

  • Efficient IP Address Allocation: Dividing a network into subnets allows too efficiently allocate IP addresses. Instead of assigning a large address block to a single network, subnetting enables the allocation of smaller, more appropriately sized address blocks to individual subnets.
  • Logical Network Segmentation: Subnetting allows logical network segmentation which enhances network security by isolating traffic within each subnet. It also enables the application of different network policies, such as Quality of Service (QoS) or access controls, to specific subnets based on their requirements.
  • Efficient Routing: Subnetting improves routing efficiency by reducing the size of routing tables. Instead of having a single large network entry in the routing table, subnetting allows for the creation of more specific subnet entries.
  • Simplified Network Management: With each subnet having its own subnet ID, network administrators can easily identify and manage different segments of the network independently. This simplifies tasks like troubleshooting, network monitoring, and resource allocation.
  • Scalability: When an organization expands its network, new subnets can be created and added without requiring major changes to the existing network infrastructure. This allows for easier network expansion and adaptation to changing requirements.