Abstract
The increase in number, diversity, and complexity of modern network devices and services creates unprecedented challenges for the currently prevailing approach of manual IP address management. Manually maintaining IP addresses could always be sub-optimal for IP resource utilization. Besides, it requires heavy human effort from network operators. To achieve high utilization and flexible scheduling of IP network addresses, it is necessary to automate the address scheduling process in the Internet of the future. Based on analysis of the gap between existing address management methods and emerging requirements of the IP network, this chapter illustrates CASM, a new approach for IP address scheduling, including its background, use cases, requirements, general framework, system architecture, interface, and workflow. A prototype system is developed and evaluated based on data from real-world networks and users in two Chinese provinces. Experimental results demonstrate that our system can largely improve the address utilization efficiency and reduce the workload of network resource maintenance.
TopBackground
Currently (2018), in most cases, IP address management systems lack an automated control mechanism. For instance, the address system integrated in Broadband Remote Access Servers (BRASes) is configured by the OAM team via CLI, and the management of IP addresses is purely artificial. Network operators manually allocate IP addresses when they are exhausted on a BRAS. Some users may have to wait until new IP blocks are assigned to the BRAS. Therefore, the timeliness of address allocation cannot be guaranteed.
Moreover, the increase in number, diversity and complexity of modern network devices and services brings new challenges for address management in IP networks:
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The efficiency of manual assignment is often sub-optimal. Real-world addresses are often managed across multiple, partly disconnected systems. These different systems lack timely interactions about address usage, leading to the situation where one network segment falls short of IP addresses while another experiences redundancy. Manual resource management could cause untimely scheduling and reduced utilization efficiency.
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The burden of address configuration on network operators with network elements could be non-trivial and heavy. IP addresses for various network systems need to be adjusted quickly due to frequent user and traffic dynamics. Besides, IPv6 transition techniques produce the need for controlling and sharing addresses among entities. Addresses of different network slices should be configured on each transition instance for High Availability (HA) purposes. Therefore, resource utilization of network systems may change very quickly. However, the current IP address management system depends on manual administration and configuration, and lacks an open, programmable interface for automatic IP resource management. This leads to a heavy maintenance burden and untimely response to dynamics.
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Inefficient and trivial manual management leads to serious fragmentation of IP address space. Networks no longer consist of large blocks of consecutive addresses, but randomly scattered sets of many small blocks or even independent individual addresses. The granularity of IPv4 address distribution is often, in some networks, as trivial as /23 or /24. Such fragmentation further decreases resource utilization efficiency and complicates manual management. Without open programmable interfaces and automated control, the clustering of small blocks or single IP addresses is difficult to achieve.
The problems with manual monitoring and management of networks have been recognized by industry. Huawei Technologies Co. Ltd. has proposed the SDN-based refined O&M to achieve nanosecond level service quality for detection in data centers. Li, Huang and Liu (2014) have proposed a communication method, communication system, resource pool management system, switch device and control device to better utilize SDN flow tables and controller resources. However, no previous effort has addressed the challenges of IP address monitoring and management.
Key Terms in this Chapter
OPEX: An ongoing cost for running a product, business, or system.
IPAM: A means of planning, tracking, and managing the IP address space used in a network. IPAM integrates DNS and DHCP so that each is aware of changes in the other (for instance, DNS knowing of the IP address assigned to a client via DHCP, and updating itself accordingly).
NFV: A network architecture concept that uses the technologies of IT virtualization to virtualize entire classes of network node functions into building blocks that may connect, or chain together, to create communication services.
Coordinator: A person or functional entity whose job is to organize activities and to negotiate with others in order to ensure they work together effectively.
CAPEX: The budget a company spends to buy, maintain, or improve its fixed assets, such as buildings, vehicles, equipment, or land.
DevOps: A software engineering practice that aims at unifying software development (Dev) and software operation (Ops).
YANG: A data modeling language used to model configuration and state data manipulated by the NETCONF protocol, NETCONF remote procedure calls, and NETCONF notifications. The YANG language was developed by the IETF NETCONF Data Modeling Language Working Group (NETMOD), and is defined in RFC 7950.