Internet Engineering Task Force C. Perkins INTERNET DRAFT Sun Microsystems 30 October 1997 Mobile Ad Hoc Networking Terminology draft-ietf-manet-term-00.txt Status of This Memo This document is a submission by the Mobile Ad Hoc Networking Working Group of the Internet Engineering Task Force (IETF). Comments should be submitted to the manet@itd.nrl.navy.mil mailing list. Distribution of this memo is unlimited. This document is an Internet-Draft. 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.'' To learn the current status of any Internet-Draft, please check the ``1id-abstracts.txt'' listing contained in the Internet-Drafts Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (North Europe), ftp.nis.garr.it (South Europe), munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or ftp.isi.edu (US West Coast). Abstract This document presents conventional definitions for many terms to be used during the discussion of various algorithms for enabling ad hoc networks of mobile computers, particularly over wireless media. Perkins Expires 30 April 1997 [Page i] Internet Draft Ad Hoc Network Terminology 30 October 1997 1. Introduction This document presents conventional definitions for many terms to be used during the discussion of various algorithms for enabling ad hoc networks of mobile computers, particularly over wireless media. With commonly agreed definitions, it is expected that protocol designers will be able to discuss more clearly the advantages and disadvantages of their algorithms. 2. Definitions for Mobile Ad Hoc Network Terms asymmetric link A link with transmission characteristics which are different depending upon the relative position or design characteristics of the transmitter and the receiver of data on the link. For instance, the range of one transmitter may be much higher than the range of another transmitter on the same medium. bandwidth The total capacity of a link to carry information (typically bits). bandwidth utilization The actual amount of information delivered over a link, expressed as a percent of the available bandwidth on that link. base station A centralized node coordinating the channel access of a population of mobile nodes within its transmission range. beacon A control message issued by a node (especially, a base station) informing all the other nodes in its neighborhood of the continuing presence of the node, possibly along with additional status information. channel A subdivision of the physical medium allowing possibly shared independent uses of the medium. Channels may be made available by subdividing the medium into distinct time slots, or distinct spectral bands, or decorrelated coding sequences. Perkins Expires 30 April 1997 [Page 1] Internet Draft Ad Hoc Network Terminology 30 October 1997 channel access protocol A protocol for mediating access to, and possibly allocation of, the various channels available within the physical communications medium. Nodes participating in the channel access protocol can communicate only when they have uncontested access to the medium, so that there will be no interference. cluster A group of nodes located within close physical proximity, typically all within range of one another, which can be grouped together for the purpose of limiting the production and propogation of routing information. control message Information passed between two or more network nodes for maintaining protocol state which is not associated to any specific application. convergence The process of approaching a state of equilibrium in which all nodes in the network agree on a consistent collection of state about the topology of the network, and in which no further control messages are needed to establish the consistency of the network topology. convergence time The time which is required for a network to reach convergence after an event (typically, the movement of a mobile node) which changes the network topology. distance vector A style of routing protocol in which, for each desired destination, a node maintains information about the distance to that destination, and a vector (next hop) towards that destination. fairness A property of channel access protocols whereby a medium is made fairly equal to all eligible nodes on the link. Fairness does not strictly imply equality, especially in cases where nodes are given link access according to unequal priority or classification. Perkins Expires 30 April 1997 [Page 2] Internet Draft Ad Hoc Network Terminology 30 October 1997 flooding The process of delivering data or control messages to every node within the ad hoc network. forwarding node A node within an ad hoc network which performs the function of forwarding datagrams from one of its neighbors to another. goodput The total bandwidth used, less the volume of control messages and protocol overhead from the data packets. hidden-terminal problem The problem whereby a transmitting node can fail in its attempt to transmit data because of destructive interference which is only detectable at the receiving node, not the transmitting node. laydown The relative physical location of the nodes within the ad hoc network. link A physical medium which can sustain data communications between multiple network nodes. link state A style of routing protocol in which every node within the network is expected to maintain information about every link within the network topology. link-level acknowledgement A protocol strategy, typically employed over wireless media, requiring neighbors to acknowledge receipt of packets (typically unicast only) from the transmitter. Such strategies aim to avoid packet loss or delay resulting from lack of, or unwanted characteristics of, higher level protocols. Perkins Expires 30 April 1997 [Page 3] Internet Draft Ad Hoc Network Terminology 30 October 1997 local broadcast The delivery of data to every node on a link (i.e., within range of the transmitter). loop-free A property of routing protocols whereby the path taken by a data packet from source to destination never transits the same intermediate node twice before arrival at the destination. MAC-layer address An address (sometimes called the link address) associated with the link interface of a node on a physical link. mobility factor The relative frequency of node movement, compared to the convergence time of the routing protocols used in the ad hoc network. neighborhood All the nodes which can receive data on the same link from one node whenever it transmits data. next hop A neighbor which has been designated to forward packets along the way to a particular destination. pathloss A reduction in signal strength caused by traversing the physical medium constituting the link. pathloss matrix A matrix of coefficients describing the pathloss between any two nodes in an ad hoc network. When the links are asymmetric, the matrix is also asymmetric. payload The actual data within a packet, not including network protocol headers which were not inserted by an application. Perkins Expires 30 April 1997 [Page 4] Internet Draft Ad Hoc Network Terminology 30 October 1997 scalability Wide applicability of a protocol to large as well as small populations of nodes participating in the protocol. scenario The tuple characterizing a class of ad hoc networks. signal strength The detectable power of the signal carrying the data bits, as seen by the receiver of the signal. source route A route to a source (i.e., a path with indications of intermediate forwarding nodes) made available to a receiver by the source of the data arriving at the receiver. spatial re-use Simultaneous use of channels with identical or close physical characteristics, but located spatially far enough apart to avoid interference (i.e., co-channel interference) system-wide broadcast Same as flooding, but used in contrast to local broadcast. throughput The amount of data from a source to a destination processed by the protocol for which throughput is to be measured for instance, IP, TCP, or the MAC protocol. Perkins Expires 30 April 1997 [Page 5] Internet Draft Ad Hoc Network Terminology 30 October 1997 Chair's Address The working group can be contacted via the current chairs: M. Scott Corson Joseph Macker Institute for Systems Research Information Technology Division University of Maryland Naval Research Laboratory College Park, MD 20742 Washington, DC 20375 Phone: +1-301-405-6630 +1-202-767-2001 E-mail: corson@isr.umd.edu macker@itd.nrl.navy.mil Author's Address Questions about this memo can be directed to: Charles Perkins Advanced Network Development Sun Microsystems, Inc. 901 San Antonio Rd. Palo Alto, CA 94303 +1-650-786-6464 +1-650-786-6445 charles.perkins@sun.com Perkins Expires 30 April 1997 [Page 6]