Automatic Configuration of IP Networks and Routers

1. Automatic Configuration of IP Networks and Routers Kenji Hori, Kiyohito Yoshihara, and Hiroki Horiuchi KDDI R&D Laboratories Inc. 2-1-15 Ohara Kamifukuoka-Shi Saitama 356-8502, Japan TEL: +81 49 278 7651 FAX: +81 49 278 7510 {hori, yosshy, hr-horiuchi}@kddilabs.jp

2. Introduction • Techniques for automatic configuration of IP networks and routers are desirable • The presence of a highly skilled user like a network operator cannot be assumed. • The deployment of automatically configurable network would be cost-effective in terms of efficient network operation and management. • Requirements for automatic configuration are identified, comparing existing proposals • ARCP is promising; however, the current version has problems to be solved: • An address management solution is not provided explicitly. • A DHCP server cannot provide anappropriate address of thedefault gateway. • Operations for discovering addition/deletion of routers(“Peer Discovery”) and for adapting router settings to network changes(“Renumbering”) can cause unstable repetitive changes of address. • “Renumbering” operations can evaporate the addresses of default gateways. • In this paper: • We identifyrequirements for an automatic configuration protocol. • We compare existing proposals with our requirements, showing that ARCP is the closest to satisfy our requirements. • We address the above problems in detail, and propose solutions. • We describe works in progress and show preliminary simulation results.

3. Requirements and comparison of existing proposals Table 1. Comparison of existing proposals

4. Overview of ARCP (1) Fig.1: Basic operation of ARCP

5. Overview of ARCP (2) Fig.2: Peer discovery and Renumbering operations

6. Solution (1): All addresses are managed originally by a DHCP server. Problem (1): Address management is not explicitly provided. Fig.4: Address assignment by solution S2 Fig.3: Address assignment by solution S1 Fig.5: Address management solution for ARCP (S2)

7. Solution (2): ARCP routers replace values of DHCP “router” option field. Problem (2): DHCP server cannot provide addresses of default gateways. Fig.6: An example of problem and solution S1 Fig.7: An Example of solution S2

8. Solution (3): The ARCP server presets static priority for each subnet. Problem (3): “Peer Discovery” and “Renumbering” operations can cause repetitive address changes. Fig.9: Solution with static priority method Fig.8: Problem of repeating Renumbering operation

9. Solution (4): ARCP routers suspends actual Renumbering operation until downstreamARCP routers are configured. Problem (4): “Renumbering” operations can evaporate default gateway address. Fig.10: Problem of evaporatingdefault gateway address Fig.11: Solution with prohibition of actual Renumbering operation

10. Simulation example of ARCP Fig.13: An example network Time of completion of accommodation[sec] Number of routers (N) Fig.14: Results with example network shown in Fig.13

11. Conclusions • In this paper: • Requirements for automatic configuration of IP networks and routers are identified first. • Comparative study on existing proposals is presented next, which shows that ARCP under standardization by IETF is the closest to satisfy requirements. • We examine a basic operation of ARCP in detail. • We address four problems and propose solutions. • In order to evaluate proposed solutions, we are developing a simulator. The work is in progress, and we present preliminary simulation results. • Future work: • Comparative simulation study of proposed solutions and standardized ARCP • Development of: • Advanced decision method of subnet selection priority in “Renumbering” operation • Adaptive and dynamic subnet resizing (variable prefix length) method • Extension for operation on IPv6 and IPv6-IPv4 mixed networks. • Hybrid method combined with other proposals • Implementation of proposed solutions and evaluation in operational networks

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