Glossary
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Cisco uBR10012 Universal Broadband Router Hardware Installation Guide
OL-18259-09
M
M13
Generic term for equipment that multiplexes DS1s into DS3s. Sometimes used to describe a specific
DS3 multiplex format. Some standards use this term to describe a synchronous multiplexing format
also know as SYNTRAN. In many cases M13 does not refer to the SYNTRAN format, but instead
refers to the format also known as M23.
M23
A method of multiplexing four DS1 signals into a DS2 signal, then multiplexing seven DS2 signals into
a DS3 signal.
MAC
Media Access Control. Lower of the two sublayers of the data link layer defined by the IEEE. The MAC
sublayer handles access to shared media.
MAC address
Standardized data link layer address that is required for each port or device that connects to a LAN.
Other devices in the network use these addresses to locate specific ports in the network, and to create
and update routing tables and data structures. MAC addresses are 6 bytes long and are controlled by
the IEEE. Also known as a hardware address, MAC-layer address, or physical address.
Major alarm
One of a group of alarm conditions that are considered the second most severe of all reportable alarms.
Major alarms affect several subscribers who connect to the reporting node. You can use the
show
facility-alarm status
IOS command to obtain more information about the problem. See also
Critical
alarm
and
Minor alarm
.
MAN
Metropolitan-area network. A network that spans a metropolitan area. Generally, a MAN spans a larger
geographic area than a LAN, but a smaller geographic area than a WAN. Compare with
LAN
and
WAN
.
Management
Information Base
See
MIB
.
Media Access
Control
See
MAC
.
Metropolitan-area
network
See
MAN
.
MIB
Management Information Base. Database of network management information that is used and
maintained by a network management protocol such as SNMP or CMIP. The value of a MIB object can
be changed or retrieved using SNMP or CMIP commands, usually through a GUI-based network
management system. MIB objects are organized in a tree structure that includes public (standard) and
private (proprietary) branches.
Minor alarm
One of a group of alarm conditions that are considered the third most severe of all reportable alarms.
Minor alarms affect a single or small number of subscribers who connect to the reporting node. You
can use the
show facility-alarm status
IOS command to obtain more information about the problem.
See also
Critical alarm
and
Major alarm
.
MLP
Multilink Point-to-Point Protocol. A method of splitting, recombining, and sequencing datagrams
across multiple logical data links.
MMF
Multimode fiber. Optical fiber supporting propagation of multiple frequencies of light. See also
Single-mode fiber
.
MPLS
Multiprotocol Label Switching. An emerging industry standard upon which tag switching is based.