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Glossary
112
December, 2005 Vodavi Telenium IP Product Guide
mobility ▪ presence ▪ collaboration ▪ convergence
MGCP Media Gateway Control Protocol. A protocol designed in 1998 to bridge between the
conventional circuit-switched PSTN and the emerging Internet Protocol packet-switched
networks. The merged specification represents a combination of the Internet Protocol Device
Control (IPDC) specification and the Simple Gateway Control Protocol (SGCP). It enables
external control and management of data communications equipment operating at the edge of
emerging multi-service packet networks – known as media gateways – by software programs,
which are known as call agents or media gateway controllers such as VoIP gateways.
MIMO MIMO (multiple input, multiple output): an antenna technology for wireless communications in
which multiple antennas are used at both the source (transmitter) and the destination (receiver).
The antennas at each end of the communications circuit are combined to minimize errors and
optimize data speed. MIMO is one of several forms of smart antenna technology, the others
being MISO (multiple input, single output) and SIMO (single input, multiple output).
MISO MISO (multiple input, single output): an antenna technology for wireless communications in
which multiple antennas are used at the source (transmitter). The antennas are combined to
minimize errors and optimize data speed. The destination (receiver) has only one antenna. MISO
is one of several forms of smart antenna technology, the others being MIMO (multiple input,
multiple output) and SIMO (single input, multiple output).
MTU Maximum Transmission Unit. The maximum size for an IP packet that can be handled by a given
network device. Packets whose size exceed a router's or computer's own MTU size will broken
down into smaller packets for reassembly at the receiving end.
Multicast A method of streaming content on an IP network in a coordinated fashion, so that all hosts
receiving the data get the same stream. The sending host sends only one data stream which is
replicated by routers and/or switches along the way. Multicast differs from broadcast in that the
multicast packets are intended only for hosts in a multicast group, and will travel across routers.
Broadcasts are intended for all hosts inside a LAN.
Multilayer
Switching Multilayer switching is an evolution of LAN and internetworking technologies. Multilayer devices
combine aspects of OSI layer 2 (the data link layer) and OSI layer 3 (the network layer) into
hybrid switches that can route packets at wire speed.
NAT Network Address Translation. A process performed by an Internet router, a firewall, or a proxy
server. NAT-ing modifies outgoing IP datagrams so that the true IP address of the host inside the
network is not known. This is done both as a security measure and as a way to enable LANs
using Private Class addressing to still use resources on the Internet.
NAPT Network Address Port Translation. Provides the same service as NAT, while also changing port
number for each connection made.
NIC Network Interface Card. The device that connects a device to a LAN. Usually in the form of a PC
expansion board, the NIC executes the code needed by the connected device to share a cable or
some other media with other stations.
Node An addressable device attached to a network. Any device with a IP address is a node, whether it
is a PC, server, router, VoIP gateway, other network device.
OC-3 Optical Carrier 3. A SONET channel equal to three DS-3s, which is equal to 155.52 million bits
per second.
One-to-Many Communications from one device to multiple devices. For example, conference calls initiated by
a single phone.
Optical
Wireless optical wireless: the combined use of conventional radio-frequency (RF) wireless and optical fiber
for telecommunication. Long-range links are provided by optical fiber and links from the long-
range end-points to end users are accomplished by RF wireless or laser systems. RF wireless at
ultra-high frequencies (UHF) and microwave frequencies can carry broadband signals to
individual computers at substantial data speeds.