Mobile Ad Hoc Network Working Group S. Daniel Park INTERNET-DRAFT Samsung Electronics Expires: September 28, 2004 March 29, 2004 DNS Discovery for global connectivity in IPv6 Mobile Ad Hoc Networks Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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. Abstract This document proposes the mechanism of DNS Discovery for global connectivity based on modified manet Router Advertisement message in IPv6 mobile ad hoc networks. 1. Introduction The global connectivity in IPv6 mobile ad hoc networks is often required for manet nodes desiring communication with the fixed Internet [GLOBALv6]. For global connectivity, manet nodes have unique global address which is used for communication to the Internet. This address is typically resolved from a DNS name. DNS resolution is a vital service for a host connected to an IPv6 network. Park Expires: September 28, 2004 [Page 1] INTERNET-DRAFT DNS Discovery in MANET March 29, 2004 This document describes the process of DNS Discovery based on IPv6 Router Advertisement (RA) to find out the address of DNS server in IPv6 Mobile Ad hoc Networks and defines new manet DNS resolver option in modified manet Router Advertisement [GLOBALv6]. The Manet DNS reslover option will allow any manet nodes to discover IPv6 addresses of DNS resolvers (with preference to global-unicast addresses). The purpose is also to enhance the efficiency of global connectivity [GLOBALv6] when internet-gateway does not provide proxy DNS function. 1.1 Terminology 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 RFC 2119 [RFC 2119]. o DNS Discovery The process of manet nodes to find out the address of DNS server, typically recursive DNS server addresses in the Internet. The addresses are used for manet nodes to obtain global addresses from a DNS name. o Manet DNS resolver (MDNSR) option The Manet DNS resolver option contains the DNS server addresses in modified manet Router Advertisement message. o internet-gateway A router which provides Internet connectivity for nodes in the manet. This router is located at the edge of manet and has a connection to both the Internet and the manet. (is described in [GLOBALv6]. 2. Overview Likewise generally IPv6 networks, an internet-gateway sends out a manet Router Advertisement message either periodically or response to a manet Router Solicitation. Moreover, the internet-gateway allows to send unsolicited manet Router Advertisements, although Park Expires: September 28, 2004 [Page 2] INTERNET-DRAFT DNS Discovery in MANET March 29, 2004 sending them periodically would generate unnecessary packets in manet. After manet nodes obtain global address, DNS queries, web browsing and that kind of services can be used in manet. The MDNSR option provides a standard mechanism for advertising DNS resolver IPv6 addresses with current manet Router Advertisement in manet. 3. MANET DNS Resolve Option The MDNSR option contains the IPv6 address of DNS server. When advertising more than one MDNSR option, as many MDNSR options as DNS servers are included in a MANET Router Advertisement message. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Pref | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + IPv6 Address of DNS Server + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Fields: o Type 11 o Length 8-bit unsigned integer. The length of option (including the type and length fields). The value 0 is invalid. Nodes MUST silently discard a MANET Router Advertisement message that contains an option with length zero. o Pref The preference of a DNS server. A 4 bit unsigned integer. A decimal value of 15 indicates the highest preference. A decimal value of 0 indicates that the DNS server can not be used. The field can be used for load balancing of DNS queries with multiple recursive DNS servers according to local policy. Park Expires: September 28, 2004 [Page 3] INTERNET-DRAFT DNS Discovery in MANET March 29, 2004 o IPv6 Address of DNS Server Recursive DNS Server's address for DNS name resolution. MDNSR option MUST be silently ignored for other Neighbor Discovery messages. 4. Security Considerations This security is essentially related to Neighbor Discovery Protocol security [DISCOVERY] and the security section in [GLOBALv6]. Security issues regarding the Neighbor Discovery Protocol are being discussed in SEND (Secure Neighbor Discovery) Working Group in IETF. 5. References [RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [GLOBALv6] Wakikawa. R. et. al., "Global connectivity for IPv6 Mobile Ad Hoc Networks", Internet Draft, November 2002. [DNSRA] Jeong, J., et. al., "IPv6 DNS Discovery based on Router Advertisement", Internet Draft, July 2003. [DISCOVERY] Narten, T., "Neighbor Discovery for IPv6", RFC 2461, December 1998. Author's Address Soohong Daniel Park Mobile Platform Laboratory, SAMSUNG Electronics Korea Phone: +82-31-200-4508 EMail: soohong.park@samsung.com Park Expires: September 28, 2004 [Page 4] INTERNET-DRAFT DNS Discovery in MANET March 29, 2004 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any effort to identify any such rights. Information on the IETF's procedures with respect to rights in standards-track and standards-related documentation can be found in BCP-11. 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