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Glossary

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MSFC

Multilayer Switch Feature Card: A route processor (parallel to an

RSM, or Route Switch Module) that is installed as a daughter card on Cisco
Catalyst 6000 series switches. See also: RSM.

mtrace (multicast traceroute)

Used to establish the SPT for a specified

multicast group.

MTU

maximum transmission unit: The largest packet size, measured in

bytes, that an interface can handle.

multicast

Broadly, any communication between a single sender and mul-

tiple receivers. Unlike broadcast messages, which are sent to all addresses on
a network, multicast messages are sent to a defined subset of the network
addresses; this subset has a group multicast address, which is specified in the
packet's destination address field. See also: broadcast, directed broadcast.

multicast address

A single address that points to more than one device

on the network by specifying a special non-existent MAC address specified
in that particular multicast protocol. Identical to group address. See also:
multicast.

multicast group

A group set up to receive messages from a source. These

groups can be established based on Frame Relay or IP in the TCP/IP protocol
suite, as well as other networks.

multicast send VCC

A two-directional point-to-point virtual control con-

nection (VCC) arranged by an LEC to a BUS, it is one of the three types of
informational link specified by phase 1 LANE. See also: control distribute
VCC and control direct VCC.

multilayer switch

A highly specialized, high-speed, hardware-based type

of LAN router, the device filters and forwards packets based on their Layer 2
MAC addresses and Layer 3 network addresses. It's possible that even Layer 4
can be read. Sometimes called a Layer 3 switch. See also: LAN switch.

multilayer switching

Multilayer switching combines layer 2, 3, and 4

switching technology and provides very high-speed scalability with low
latency. This is provided by huge filter tables based on the criteria designed
by the network administrator.

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