MANET Working Group Sanghyun Ahn Internet Draft University of Seoul Expires: June 12, 2012 December 19, 2011 A Centralized MANET DNS Mechanism draft-ahn-manet-centralized-dns-00.txt Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. This document may not be modified, and derivative works of it may not be created, except to format it for publication as an RFC or to translate it into languages other than English. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on June 12, 2012. Copyright Notice Copyright (c) 2011 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/ license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Ahn Expires June 12, 2012 [Page 1] Internet-Draft A Centralized MANET DNS Mechanism December 2011 Abstract This document describes a Domain Name System (DNS) mechanism for the MANET based on the centralized DNS mechanism used in the wired Internet. In order to adapt to the dynamic topology changes of the MANET, the mechanism handles the movement of the DNS server and the MANET merge/partition. Table of Contents 1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Operations . . . . . . . . . . . . . . . . . . . . . . . . . . 3 4.1 DNS Server Discovery . . . . . . . . . . . . . . . . . . . . . 3 4.2 Maintenance of Domain Names and Binding Information . . . . 4 4.3 Network Merge and Partition . . . . . . . . . . . . . . . . 4 5. Message Format . . . . . . . . . . . . . . . . . . . . . . . . 4 6. Other Considerations . . . . . . . . . . . . . . . . . . . . . 4 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 5 Ahn Expires June 12, 2012 [Page 2] Internet-Draft A Centralized MANET DNS Mechanism December 2011 1. Requirements notation The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 2. Introduction The centralized DNS mechanism works based on unicast communications, so it is more efficent in the resource-limited MANET than the multicast-based DNS mechanisms proposed in [1][2]. However, the centralized DNS mechanism may confront with the following problems in the MANET environment. - the problem of server non-existence - the problem of frequent updates of the IP address and domain name bindings In this draft, we describe how to adapt the centralized DNS mechanism to the MANET by resolving the above mentioned problems. 3. Terminology TBD. 4. Operations 4.1 DNS Server Discovery MANET nodes discover the DNS server by sending the DSN Server Solicitation and the DNS Server Advertisement messages. The node wishing to obtain the address of the DNS server broadcasts a DNS Server Solicitation message and waits for a DNS Server Advertisement message from the DNS server. If no DNS Server Advertisement message is received for the given time interval, the node assumes that there is no DNS server and broadcasts a DNS Server Advertisement message to announce itself as the DNS server. If there exists the DNS server, the DNS server will receive the DNS Server Solicitation message and unicasts a DNS Server Advertisement message to the requesting node as a response. The DNS server is required to broadcast DNS Server Advertisement messages periodically to announce its existence. Ahn Expires June 12, 2012 [Page 3] Internet-Draft A Centralized MANET DNS Mechanism December 2011 4.2 Maintenance of Domain Names and Binding Information A node registers its domain name by unicasting a DNS Register message to the DNS server and the server determines whether the domain name is already used by another node or not. To request for the name service, a node unicasts a DNS Name Query message to the DNS server and, then, the DNS server reponses to the request by unicasting the corresponding DNS Name Response message. If a node wants to change its domain name, it unicasts a DNS Name Change message with its new domain name to the DNS server. If a node wishes to leave the MANET, it sends a DNS Name Release message to the DNS server. 4.3 Network Merge and Partition If a node receives no DNS Server Advertisement message from the DNS server for the given time interval, it assumes that the DNS server does not exist in the network any more. Then, the node becomes the new DNS server and broadcasts a DNS Server Advertisement message. Due to node or DNS server movement, there may exist more than one DNS server within the MANET. The multiple DNS server existence can be detected by a DNS server when it receives a DNS Server Advertisement message from another DNS server. In that case, only one DNS server with the highest priority is chosen as the DNS server by using a given tie breaking rule. The DNS server with a lower priority gives up its role as the DNS server and hands over its DNS name table to the highest priority DNS server by sending a DNS Register message. 5. Message Format TBD. 6. Other Considerations TBD. Ahn Expires June 12, 2012 [Page 4] Internet-Draft A Centralized MANET DNS Mechanism December 2011 References [1] S. Cheshire and M. Krochmal, "Multicast DNS," Internet Draft, 2005. [2] J. Jeong, J. Park and H. Kim, "Name Service in IPv6 Mobile Ad- hoc Network Connected to the Internet," IEEE PIMRC, pp.1351-1355, 2003. Authors' Addresses Sanghyun Ahn University of Seoul 90, Cheonnong-dong, Tongdaemun-gu Seoul 130-743 Korea Email: ahn@uos.ac.kr Ahn, et al. Expires June 12, 2012 [Page 5]