Mobile Ad hoc Networking (MANET) J. Haerri Internet-Draft Karlsruhe Institute of Technology Intended status: Experimental (KIT), Germany Expires: January 15, 2009 C. Bonnet F. Filali Institut Eurecom, France July 14, 2008 MANET Position and Mobility Signaling Format draft-haerri-manet-position-signaling-01 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. 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 January 15, 2009. Haerri, et al. Expires January 15, 2009 [Page 1] Internet-Draft MANET Position Signaling July 2008 Abstract This document describes an extension to the node metric TLV defined in the MetricTLV document to specify a configurable structure to exchange position and mobility information for MANET protocols. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Applicability Statement . . . . . . . . . . . . . . . . . . . 5 4. Protocol Overview and Functioning . . . . . . . . . . . . . . 6 5. Representing Position . . . . . . . . . . . . . . . . . . . . 7 6. Representing Time . . . . . . . . . . . . . . . . . . . . . . 8 7. Metric TLV containing Position Information . . . . . . . . . . 9 7.1. Message TLV . . . . . . . . . . . . . . . . . . . . . . . 9 7.2. Address Block TLV . . . . . . . . . . . . . . . . . . . . 9 7.3. Position Information Semantic . . . . . . . . . . . . . . 10 7.3.1. Constraints . . . . . . . . . . . . . . . . . . . . . 12 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 9. Security Considerations . . . . . . . . . . . . . . . . . . . 14 10. Normative References . . . . . . . . . . . . . . . . . . . . . 15 Appendix A. Message Layout . . . . . . . . . . . . . . . . . . . 16 A.1. Mobility TLVs . . . . . . . . . . . . . . . . . . . . . . 16 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18 Intellectual Property and Copyright Statements . . . . . . . . . . 19 Haerri, et al. Expires January 15, 2009 [Page 2] Internet-Draft MANET Position Signaling July 2008 1. Introduction The generalized packet/message format [PacketBB] specifies a signaling format which MANET routing protocols can employ for exchanging protocol information. This format presents the ability to express and associate attributes to packets, messages or addresses, by way of a general TLV (type-length-value) mechanism. The MANET MetricTLV document [MetricTLV] specifies a general metric TLV structure compatible with the generalized packet/message format and which can be used by MANET protocols that need to use and exchange metrics associated with a link or a node. Position information is a particular metric that is associated with a node and that may be beneficial for MANET protocols as described in [GeoProblemStatement]. Position information is usually not a unique metric but is associated with other metrics such as speed, azimuth or sampling time. Although the MANET Metric document [MetricTLV] is able to specify the individual structure of each of them, due to their correlations and the possible different transmission formats that are still under discussion, we propose to describe a common structure for the exchange of position and mobility information in a separate document. This document specifies a Mobility structure, which MAY be used by any MANET routing protocol that needs to exchange geolocalization information using the MANET Metric format and the generalized MANET packet/message format. If it is used as a message TLV, it allows a receiving node to obtain the position, the azimuth or the velocity of a sending node in a configurable way. If it is used as an address block TLV, it allows a receiving node to obtain the position, the azimuth or the velocity of nodes different from the sending node. Haerri, et al. Expires January 15, 2009 [Page 3] Internet-Draft MANET Position Signaling July 2008 2. 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 [RFC2119]. Additionally, this document uses the terminology from [PacketBB] and [MetricTLV], and introduces the following terminology GPS - Global Positioning System. A geolocalization system developped and operated by the US Department of Defense that is able to provide accurate worldwide coordinates of devices equiped with GPS receivers. A similar European system is currently under developpement under the name of Galileo. The GPS system does not work without a clear access to at least 3 satellites, thus is inoperable for indoor positioning. GPS-free Positioning - A set of techniques that has been developped in order to provide a mean of localization in situation when a clear access to satellites is not possible. Most of the methods uses multilateration techniques and requires either a formal training, or an anchor node that knows its accurate position. Time - The universal GPS time expressed in seconds. Longitude - The longitude describes the location of a place on Earth east or west of a north-south line called the Prime Meridian located in Greenwich, UK. Longitude is given as an angular measurement ranging from 0 degree at the Prime Meridian to +180 degree eastward and -180 degree westward. Latitude - The latitude gives the location of a place on Earth north or south of the equator. Latitude is an angular measurement ranging from 0 degree at the Equator to 90 degree at the poles. Elevation - The elevation is the altitude of an object from a known level or datum. Common datums are mean sea level and the surface of the WGS-84 geoid used by GPS. Azimuth - Azimuth is the horizontal component of a direction, measured around the horizon, from the north toward the east in the northern hemisphere, and from the south toward the west in the southern hemisphere. Mobility - mobility information related to a specific address, which MAY consist of a longitude, latitude or elevation, a velocity, an azimuth, and the time this mobility information has been sampled. Haerri, et al. Expires January 15, 2009 [Page 4] Internet-Draft MANET Position Signaling July 2008 3. Applicability Statement The mobility structure described in this document is applicable in conjuction with [MetricTLV] whenever the transmission of the position, the velocity or the azimuth of a node or of a set of nodes is required by a MANET protocol using the generalized MANET packet/ message format [PacketBB]. Haerri, et al. Expires January 15, 2009 [Page 5] Internet-Draft MANET Position Signaling July 2008 4. Protocol Overview and Functioning This specification does not describe a protocol, nor does it mandate specific node or protocol behavior. Rather, it describes mechanisms for encoding position information using an extension to the TLV mechanism of [MetricTLV] and [PacketBB]. Protocols using the structure specified in this documents MUST transmit position information of the local node using a message TLV, while general position information of other nodes MUST be encoded using an address TLV block. Haerri, et al. Expires January 15, 2009 [Page 6] Internet-Draft MANET Position Signaling July 2008 5. Representing Position This document specifies an extension to the metric TLV structure to transmit position information consisting of the 3-tuple longitude, latitue and elevation, optionally added with the speed and azimuth of a mobile node. This document assumes the availability of a GPS (Global Positioning System) for the sampling of these informations, but is not limited to it as long as any other system is able to provide a similar position information format. This document proposes to transmit mobility information according to the following two structure formats: o A standard format able to support the data format provided by GPS devices. o A reduced format that encodes the minimum required mobility data in multiples of a byte in order to limit the size of a TLV containing mobility information and thus reducing the transmission overhead. Due to the specificity of position information, all possible values MUST be representable. An exponential representation is therefore not possible. Accordingly, the exprep field specified in [MetricTLV] MUST be cleared. Haerri, et al. Expires January 15, 2009 [Page 7] Internet-Draft MANET Position Signaling July 2008 6. Representing Time In order to reconstruct the current position or have an estimation of the freshness of the position information, this document also specifies the transmission of the position sampling time. As no synchronization is assumed in this document, the time shared by all nodes using this document MUST be the GPS time. GPS (Global Positioning System) time is the atomic time scale implemented by the atomic clocks in the GPS ground control stations and the GPS satellites themselves. GPS time is expressed as a number of seconds since the beginning of the GPS epoch on Sunday January 6th 1980 at 0:00 UTC. Due to the specificity of the sampling time of position information, all possible values MUST be representable. A time representation similar to [TimeTLV] is therefore not possible, and neither is any exponential representation. Accordingly, the exprep field specified in [MetricTLV] MUST be cleared. The GPS time is usually represented by an 64 bit field. In order to reduce the size of this field, a new reference point common to any node in the network may be used instead of the GPS epoch. Yet, the specification of methods to reduce the size of the GPS sampling time it is out of scope of this document. However, this document specifies an optional reduced size field of 16 bits for the transmission of such reduced information. Haerri, et al. Expires January 15, 2009 [Page 8] Internet-Draft MANET Position Signaling July 2008 7. Metric TLV containing Position Information This specification defines an extended structure for one message block TLV structure or one address block TLV structure for the inclusion of position information. When using the structure described in this document, both TLV structures MUST have the thastypeext bit set to 1 in the tlv-semantics field as defined in [PacketBB]. 7.1. Message TLV A position metric message TLV SHOULD be used for signaling position information associated with the local node. If a metric message TLV is to be included in a message, the originator-address MUST be included in the msg-header-info as defined in [PacketBB]. The of the metric message TLV is further defined in this document : The 'exprep' bit of the as defined in [MetricTLV] MUST be cleared, as an exponential representation MUST NOT be used for Mobility information. The field as specified in [MetricTLV] contains a 7 bit field containing the value type of the metric being coveyed. This document proposes the following layout to specify the presence of position information: +--------------+------------------------+ | M-value | Value Representation | +--------------+------------------------+ | TBD | Mobility Metric | +--------------+------------------------+ Figure 1 7.2. Address Block TLV A position metric address block TLV SHOULD be used for signaling a node metric associated with any other node than the local node. The of the metric address block TLV is further defined in this document: Haerri, et al. Expires January 15, 2009 [Page 9] Internet-Draft MANET Position Signaling July 2008 The 'exprep' bit of the as defined in [MetricTLV] MUST be cleared, as an exponential representation MUST NOT be used for Mobility information. The 'outbound' and 'inbound' bits of the as defined in [MetricTLV] MUST be cleared according to the following layout: +----------+----------+----------------------+ | Inbound | Outbound | Value Representation | +----------+------+--------------------------+ | 0 | 0 | Node Metric | +----------+----------+----------------------+ Figure 2 The field as specified in [MetricTLV] contains a 5 bit field containing the value type of the metric being coveyed. This document proposes the following layout to specify the presence of position information: +--------------+------------------------+ | M-value | Value Representation | +----+----+----+----+----+----+----+----+ | TBD | Mobility Metric | +--------------+------------------------+ Figure 3 7.3. Position Information Semantic The field of a Metric TLV when the specifies a Mobility metric is encoded according to the following layout = {}* where: is an 8 bit field which describes the stucture of the tag. Haerri, et al. Expires January 15, 2009 [Page 10] Internet-Draft MANET Position Signaling July 2008 bit 0 (position bit): TLV with this bit cleared ('0') does not contain the position of the local node or of the address in the respective address block. TLVs with this bit set ('1') contains position information. bit 1 (velocity bit): TLV with this bit cleared ('0') does not contain the velocity of the local node or of the address in the respective address block. TLVs with this bit set ('1') contains the velocity. bit 2 (azimuth bit): TLV with this bit cleared ('0') does not contain the azimuth of the local node or of the address in the respective address block. TLVs with this bit set ('1') contains the azimuth. bit 3 (reduced format bit): TLV with this bit cleared ('0') does not contain position information of the address in the respective address block or of the local node using the reduced format. TLVs with this bit set ('1') contains position information encoded using a reduced format. bits 4-7 are RESERVED They MUST be cleared ('0')to be in conformance with this version of the specification. is a field containing the mobility parameters. The length of this field may be obtained from the field. The field is specified by: = {??