m 1. abbrev. meter. See meter. 2. abbrev. milli-. See resemblingM the letter “M.” This is a common con- milli-. figuration in hub topology satellite communications. M 1. abbrev. mega-. See mega. 2. symb. mixed po- Newer satellites are being designed for intersatellite larization (ITU). communication, so the signal goes from an Earth sta- M bit, Mark bit, More bit In X.25 network data tion to a satellite, to another satellite and then down transmissions, a signal bit used to indicate that ad- to Earth again, thus forming a shape like three sides ditional packets in a sequence are to be expected. A of a rectangle rather than the letter M, as shown in bit set to 1 or “true” indicates further packets will be the Basic hop/M hop diagram. coming, whereas 0 or “false” signals that packets M port In a Fiber Distributed Data Interface (FDDI) were (intentionally) not sent. This helps the receiv- network topology, this is an extra port on a concen- M ing system to distinguish between packets not sent trator used to attach other nodes in a branching tree and lost packets. In Realtime Transport Protocol topology. (RTP), the M bit can signal the transport of at least M ports can be on both single attachment and dual one complete media frame or the remaining fragment attachment concentrators. The M port is an addition in a frame. For frames fragmented across multiple to the basic attachment to the FDDI network. On a RTP packets, the M bit can signal frame boundaries. dual attachment station, a redundant link can be cre- See D bit, Q bit. ated by connecting the A and B ports on different con- M hop A type of pattern that results when commu- centrators on the M ports. On a single attachment nications transmissions are bounced from an Earth concentrator, the M port may be connected to the S station to an airborne receiver, back to an Earth sta- port. M ports are never connected to one another. The tion or intermediary hub, up to an airborne receiver other end of the M port may be attached to a patch and back down to the final receiving station, thus panel through a data grade cable. Basic hop M hop The left diagram illustrates a basic hop to a satellite and another back to an Earth receiving station. The one on the right shows how the hops can be repeated to pass through an intermediate station or hub, and then to the final receiver. There may be a number of reasons for sending to an intermediate hub, including amplification, filtering of the broadcast channels, and redistribution to subscribers through Earth stations at more than one location. © 2002 by CRC Press LLC ITU-T M Series Recommendations M.3604 Application of maintenance principles to ISDN primary rate access Scope, Philosophy, General Principles M.3605 Application of maintenance principles to static multiplexed ISDN basic rate M.10 Scope and application of recommenda- access tions for maintenance of telecom. net- M.3610 Principles for applying TMN concept works and services to the management of B-ISDN M.15 Maintenance considerations for new M.3611 Test management of B-ISDN ATM systems layer using the TMN M.20 Maintenance philosophy for telecom. M.3620 Principles for the use of ISDN test networks calls, systems, and responders M.21 Maintenance philosophy for telecom. M.3621 Integrated management of ISDN cus- services tomer access M.32 Principles for using alarm info for M.3640 Management of the D-channel – data maintenance of international transmis- link layer and network layer sion systems and equipment M.3641 Management info model for manage- M.560 International telephone circuits – prin- ment of data link and network layer of ciples, definitions, and relative trans- ISDN D-channel mission levels M.3650 Network performance measurements of M.1130 General definitions and general prin- ISDN calls ciples of operation/maintenance M.3660 ISDN interface management services proced. to be used in satellite mobile systems Monitoring, Maintenance, Performance, M.1140 Maritime mobile telecom. services via Service, Testing, Misc., etc. satellite M.34 Performance monitoring on interna- M.1301 General description and operational tional transmission systems and equip- proced. for international SDH leased ment circuits M.35 Principles concerning line-up and M.1535 Principles for maintenance info to be maintenance limits exchanged at customer contact point M.50 Use of telecom. terms for maintenance (MICC) M.60 Maintenance terminology and defini- M.1537 Definition of maintenance info to be tions exchanged at customer contact point M.70 Guiding principles on general mainte- (MICC) nance organiz. for telephone-type inter- M.3100 Generic network info model national circuits M.3600 Principles for management of ISDNs M.75 Technical service Numbering M.80 Control stations M.85 Fault report points M.320 Numbering of channels in group M.90 Sub-control stations M.330 Numbering of groups within super- M.100 Service circuits group M.110 Circuit testing M.340 Numbering of supergroups within M.120 Access points for maintenance mastergroup M.125 Digital loopback mechanisms M.350 Numbering of mastergroups within M.160 Stability of transmission supermastergroup M.450 Bringing new international transmis- M.380 Numbering in coaxial systems sion system into service M.390 Numbering in systems on symmetric M.460 Bringing international group, super- pair cable group, etc. links into service M.400 Numbering in radio-relay links or M.470 Setting up and lining up analog chan- open-wire line systems nels for international telecom. services M.410 Numbering of digital blocks in trans- M.475 Setting up and lining up mixed analog/ mission systems digital channels for international telecom. services ISDN M.495 Transmission restoration and transmis- M.3600 Principles for management of ISDNs sion route diversity: terminology and M.3602 Application of maintenance principles general principles to ISDN subscriber installations M.496 Functional organiz. for automatic trans- M.3603 Application of maintenance principles mission restoration to ISDN basic rate access M.500 Routine maintenance measurements to be made on regulated line sections © 2002 by CRC Press LLC M.510 Readjustment to nominal value of a M.721 System availability info point regulated line section (on symmetric M.722 Network management point pair line, coaxial line or radio-relay link) M.723 Circuit control station M.520 Routine maintenance on international M.724 Circuit sub-control station group, supergroup, etc. links M.725 Restoration control point M.525 Automatic maintenance procedures for M.726 Maintenance organization for wholly international group, supergroup, etc. digital international automatic and semi- links automatic telephone service M.530 Readjustment to the nominal value of M.729 Maintenance organization for interna- an international group, supergroup, etc. tional public switched telephone circuits link for data transmission M.535 Special maintenance procedures for M.730 Maintenance methods multiple destination, unidirectional M.731 Subjective testing (MU) group and supergroup links M.732 Signaling and switching routine mainte- M.540 Routine maintenance of carrier and pi- nance tests and measurements lot generating equipment M.733 Transmission routine maintenance mea- M.556 Setting up and initial testing of digital surements on automatic and semi-auto- channels on international digital path or matic telephone circuits block M.734 Exchange of info on incoming test facili- M.562 Types of circuit and circuit section ties at international switching centers M.565 Access points for international tele- M.760 Transfer link for common channel Sig- phone circuits naling System 6 M.570 Constitution of circuit; preliminary ex- M.762 Maintenance of common channel Signal- change of info ing System 6 M.580 Setting up and lining up international M.800 Use of circuits for voice-frequency teleg- circuit for public telephony raphy M M.585 Bringing international digital circuit M.810 Setting up and lining up international into service voice-frequency telegraph link for public M.590 Setting up and lining up circuit fitted telegraph circuits (50-, 100-, and 200- with a compandor baud modulation rates) M.600 Organization of routine maintenance M.820 Periodicity of routine tests on interna- measurements on circuits tional voice-frequency telegraph links M.605 Routine maintenance schedule for in- M.830 Routine measurements to be made on ternational public telephony circuits international voice-frequency telegraph M.610 Periodicity of maintenance measure- links ments on circuits M.850 International time division multiplex M.620 Methods for carrying out routine mea- (TDM) telegraph systems surements on circuits M.880 International phototelegraph transmission M.630 Maintenance of circuits using control M.900 Use of leased group and supergroup links chart methods for wide-spectrum signal transmission M.650 Routine line measurements to be made (data, facsimile, etc.) on line repeaters of audio-frequency M.910 Setting up and lining up international sections or circuits leased group link for wide-spectrum sig- M.660 Periodical in-station tests of echo sup- nal transmission pressors complying with Recommenda- M.1010 Constitution and nomenclature of inter- tions G.161 and G.164 national leased circuits M.665 Testing of echo cancellers M.1012 Circuit control station for leased and spe- M.670 Maintenance of circuit fitted with cial circuits compandor M.1013 Sub-control station for leased and special M.675 Lining up and maintaining international circuits demand assignment circuits (SPADE) M.1014 Transmission maintenance point (interna- M.710 General maintenance organiz. for inter- tional line) (TMP-IL) national automatic and semi-automatic M.1015 Types of transmission on leased circuits telephone service M.1016 Assessment of service availability perfor- M.715 Fault report point (circuit) mance of international leased circuits M.716 Fault report point (network) M.1020 Character.