CIDR Addressing, Address Assignment Efficiency
The Internet has experienced dramatic growth due, in part, to its high levels of adaptability and flexibility. One reason for this flexibility is that there is no overall authority dictating how connections must be done and what applications can be deployed. This lack of an authority also means that growth is driven by individual users and organizations.
In the early 1990s, the Internet Engineering Task Force (IETF) became concerned about the projected exhaustion of IPv4 address space under the existing practice of assigning either Class A networks (>16 million hosts), Class B Networks (>65,000 hosts), or Class C Networks (256 hosts) whenever they were requested. The IETF made recommendations concerning justifications for requested address space. By 1992, several meetings and working groups produced the concept of Classless Inter-Domain Routing (CIDR) to allow network design and assignment to better match the anticipated number of networked elements. One negative side effect was to create more routes to different networks because of the subdivision that CIDR provided. This then led to the practice of hierarchical address assignment, which allowed the practice of "supernetting" (as opposed to subnetting), the aggregation of contiguous networks reachable through a single router into one aggregate route.
CIDR subnetting can reduce efficiency of a given network when that network needs to be expanded.
To complete this Discussion, answer the following questions:
- What are some other ways you can think of to achieve efficient use of available public addresses? This can include any combination of current practices, including NAT, DHCP, dynamic addresses and bridging, or others you may propose.
- How efficient is your proposal's address utilization compared to CIDR subnetting? Analyze its effect on a production network, and propose a plan for transitioning to this proposal from a current production network. What are some of its advantages and disadvantages? Why do you think this is the best way?