MANET Working Group Sanghyun Ahn Internet Draft University of Seoul Expires: June 13, 2016 December 22, 2015 Architecture of Multipath Routing Protocols for MANET draft-ahn-manet-multipath-architecture-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 13, 2016. Copyright Notice Copyright (c) 2015 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 13, 2016 [Page 1] Internet-Draft Architecture of Multipath Routing Protocols December 2016 Abstract This document describes the architecture on the protocols providing multiple routes between a given source and destination node pair in a mobile ad hoc network (MANET). Table of Contents 1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Terminoloy . . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Architecture of MANET Multipath Routing Protocols. . . . . . . 4 4.1 Route Discovery Phase . . . . . . . . . . . . . . . . . . . . 4 4.2 Route Determination Phase . . . . . . . . . . . . . . . . . . 5 4.3 Route Maintenance Phase . . . . . . . . . . . . . . . . . . . 5 5. Other Considerations . . . . . . . . . . . . . . . . . . . . . 6 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 6 Ahn Expires June 13, 2016 [Page 2] Internet-Draft Architecture of Multipath Routing Protocols December 2016 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 mobile ad hoc network (MANET) is composed of a number of mobile nodes which can communicate with each other through multiple wireless links without the help of a wired infrastructure. Therefore, in the MANET, the route connectivity tends to be very unstable. This route unstability can be mitigated by providing more than one route to a source and destination node pair. In recent years, there have been intensive studies done on multipath routing protocols for the MANET [1]. Also, multipath routing protocols may have the advantage of providing load balancing by distributing data traffic to a number of routes. On the other hand, it may incur more control message overhead to set up multiple routes. In this draft, we define the architecture of the MANET multipath routing protocol. 3. Terminology Primary Route The route with the best quality among the selected routes Alternative Route The selected routes not chosen as the primary route Route Discovery Phase The procedure of finding all the possible routes from the source to the destination; initiated by the source Route Determination Phase The procedure of selecting routes which meet the given route performance criteria Route Maintenance Phase The procedure of recovering the route used for the data delivery Ahn Expires June 13, 2016 [Page 3] Internet-Draft Architecture of Multipath Routing Protocols December 2016 Route Discovery Message The message used during the Route Discovery phase to find possible routes Route Determination Message The message used during the Route Determination phase to select routes Route Maintenance Message The message used during the Route Maintenance phase to recover a route; sent back to the source Base MANET Unicast Routing Protocol The MANET unicast routing protocol on which the MANET multipath routing protocol is based 4. Architecture of MANET Multipath Routing Protocols MANET multipath routing protocols consist of three phases; the Route Discovery phase, the Route Determination phase, the Route Maintenance phase. The Route Discovery phase is the procedure of figuring out all the possible routes from the given source to the destination. In the Route Determination phase, the appropriate multiple routes from the available routes found in the Route Discovery phase are determined. In the Route Determination phase, one of the selected routes may be chosen as the primary route on which all the data packets from the source are sent on to the destination. In this case, the other route(s) act(s) as the alternative backup path(s) which are reserved for the use in the Route Maintenance phase. Or, all the selected routes in the Route Determination phase may be used for the delivery of data packets from the source to the destination.This is called the per-packet allocation [2] in which each data packet is placed on one of the selected routes randomly or based on some scheduling scheme. 4.1 Route Discovery Phase When a source node wishes to send data packets to a destination node, it initiates the Route Discovery phase by sending out one or more route discovery message. This route discovery message may be broadcast to the entire network to figure out all the possible routes to the destination. The propagation method of the route discovery message is decided by the base MANET unicast routing protocol. When an intermediate node receives a route discovery message, the node has to decide whether to forward the message or not based on the base MANET unicast routing protocol or other criteria. Ahn Expires June 13, 2016 [Page 4] Internet-Draft Architecture of Multipath Routing Protocols December 2016 4.2 Route Determinination Phase The routes for a given source and destination node pair may be determined (i) by only the destination or (ii) by both of the destination and the intermediate nodes and/or (iii) by the source. If only the destination is given with the right to select the routes, the quality of the selected multiple routes can be satisfied easily according to the given criteria. But, for this, the destination has to be given with the information on all the possible routes between the source and the destination. That is, an intermediate node has to forward a received route discovery message towards the destination. On the other hand, if the intermediate nodes are involved in selecting routes, a received route discovery message may not be forwarded if the intermediate node finds a path from the source to the destination based on the received route discovery message and its own route to the destination. In this case, the selected routes may not be good compared with (i). However, (ii) may incur less route discovery overhead than (i). The source may be involved in route determination when (i) or (ii) is used to enhance the quality of the selected routes. Among the selected routes, one route can be chosen as the primary route which is the only route used for the data delivery. While the primary route works normally, the other selected routes become the alternative routes. That is, upon the primary route failure, one of the alternative is chosen as the primary route. Or, all the selected routes can be used for the data delivery. In this scheme, a data packet is sent on one of the selected routes based on a route scheduling mechanism. This scheme can provide higher load balancing effect than the above-mentioned primary path-based scheme. 4.3 Route Maintenance Phase If a node recognizes a link failure (i.e., a given number of data transmission failures over a link), it initiates the Route Maintenance phase by sending out a route maintenance message back to the source. A route maintenance message may be intercepted by an intermediate node on the reverse route to the source for fast route recovery. For this, the intermediate node has to have the alternative route information to the destination. This capability can be achieved by the route maintenance mechanism of the base MANET unicast routing protocol. For the primary path-based scheme, when the source node receives a route maintenance message, it selects one of the alternative routes as the primary path. Ahn Expires June 13, 2016 [Page 5] Internet-Draft Architecture of Multipath Routing Protocols December 2016 On the other hand, when all the selected routes are used for the data delivery, the source node receiving the route maintenance message ignores the message if it has at least one route available. Otherwise, the source initiates the Route Discovery phase. 5. Other Considerations TBD References [1] M. Tarique, K. E. Tepe, S. Abidi and S. Erfani, "Survey of Multipath Routing Protocols for Mobile Ad Hoc Networks," Journal of Network and Computer Applications, November 2009. [2] C. Taddia and G. Mazzini, "Per-Packet Allocation Strategies for Heterogeneous Multichannel Wireless Networks," International Conference on Wireless Networks, Communications and Mobile Computing, June 2005. Author's Address Sanghyun Ahn University of Seoul 90, Cheonnong-dong, Tongdaemun-gu Seoul 130-743 Korea Email: ahn@uos.ac.kr Ahn Expires June 13, 2016 [Page 6]