MANET Working Group Sanghyun Ahn Internet Draft Hyun Yu Expires: June 12, 2012 University of Seoul December 19, 2011 An AODV Extension for Stable Route Selection draft-ahn-manet-aodv-stableroute-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, et al. Expires June 12, 2012 [Page 1] Internet-Draft Stable Route Selection in AODV December 2011 Abstract This document describes an enhancement on AODV that can allow a route with more stable intermediate nodes to be selected. For this, a new field, called the 'RouteStability' field, is introduced in the RREQ message and in the AODV routing table entry. Table of Contents 1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Use of the RouteStability Field . . . . . . . . . . . . . . . 3 5. Message Format . . . . . . . . . . . . . . . . . . . . . . . . 4 6. Other Considerations . . . . . . . . . . . . . . . . . . . . . 4 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 4 Ahn, et al. Expires June 12, 2012 [Page 2] Internet-Draft Stable Route Selection in AODV 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 In a MANET, nodes can have mobility, resulting in route instability. In AODV [1], a route is discovered by flooding RREQs and the route with the minimum hop count is chosen without considering link stability. Therefore, if any nodes in a chosen route move, the route has high possibility of link breaks which incur route reestablishment. This route reestablishment causes service disruption as well as high control message overhead. In this draft, we define a new field, called the RouteStability field, in the RREQ message of AODV so that the stability of the route discovered by the RREQ message can be informed to the destination. Also, to allow RREQ messages which have discovered more stable routes than the previous RREQ messages with the same destination sequence number to be forwarded, a new field, called the RouteStability field, is added to the entry of the routing table. How to determine the stability of a route is out of the scope of this draft. 3. Terminology RouteStability The metric to indicate the stability of a route (a larger 'RouteStability' value means more stable) 4. Use of the RouteStability Field In this mechanism, we assume that each MANET node can compute the stability of itself. How to calculate this stability information is out of the scope of this draft. In order to allow more stable routes to be selected, we define a new field both in the RREQ message and in the routing table entry, called the 'RouteStability' field, which indicates the stability of the route. Ahn, et al. Expires June 12, 2012 [Page 3] Internet-Draft Stable Route Selection in AODV December 2011 When a node receives an RREQ message, it compares the value in the 'RouteStability' field of the RREQ message and that of the corresponding routing table entry. If the value in the RREQ message is larger than that of the routing table entry, the node updates the 'RouteStability' field of the routing table entry to that of the RREQ message and updates the value of the 'RouteStability' field of the RREQ message and forwards the RREQ message. Otherwise, it discards the RREQ message. If a MANET node receives the first RREQ message destined to itself, it waits for more RREP messages during a given time interval, instead of sending back an RREP message for the first RREQ message. After the given time interval, the destination node sends an RREP message in response to the RREQ message with the largest 'RouteStability' value. 5. Message Format TBD. 6. Other Considerations TBD. References [1] C. Perkins, E. Belding-Royer and S. Das, "Ad hoc On-Demand Distance Vector (AODV) Routing," RFC 3561, July 2003. Authors' Addresses Sanghyun Ahn University of Seoul 90, Cheonnong-dong, Tongdaemun-gu Seoul 130-743 Korea Email: ahn@uos.ac.kr Hyun Yu University of Seoul 90, Cheonnong-dong, Tongdaemun-gu Seoul 130-743 Korea Email: finalyu@gmail.com Ahn, et al. Expires June 12, 2012 [Page 4]