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11 Glossary
MAC address – Media Access
Control address
Twelve-character hexadecimal hard-
ware address organised in pairs (e.g.
1A-2B-3C-4E-5F-66) of an internal or
external network adapter/network-
capable device interface (computer,
router, etc.) for wireless and/or wired
network connection (also called
Ethernet address, Ethernet ID, air
-
port ID or Wi-Fi address). The MAC
address can be used as a basis for
automatic configuration of devices
connected to an IP-based network
and is used by various network proto
-
cols (e.g. DHCP). In theory, the MAC
address of a network-capable device
should be globally unique and it was
regarded as a unique identifier within
a network. The preset MAC address
of a network adapter itself cannot
be changed. However, the MAC
addresses to be communicated can
be changed as desired by software
or created at random using existing
device functions (e.g. smartphones)
in order to prevent unique identifica-
tion or to use replacement devices
with the same ID. The MAC address
also contains the manufacturer code
as a six-character prefix.
MJPEG – Motion JPEG
Process (video codec) for single
frame compression of a video
sequence to be transmitted, which
is used on network cameras. MJPEG
is a process used to compress the
content of the single frames. The
video stream is transmitted in JPEG-
compressed single frames via the
HTTP protocol.
Multicast
An information and communica
-
tion technology type of point-to-
multipoint connection for efficiently
sending data via a multicast IP
address. Information is sent from the
source just once, duplicated in the
IP-based network and automatically
forwarded to all the pre-determined
recipients. This relieves the load on
the sending network components
(e.g. server) as the duplication and
distribution of the sent informa
-
tion takes place via the distribution
components (e.g. multicast-capable
switches). All distribution compo
-
nents within a network must be
multicast-capable. Access is multi-
cast-capable.
->
Unicast
NAT – Network Address
Translation
Network address translation method
for automatic replacement of
address information in data packets
with other information, to connect
various networks (e.g. private and
public IP-based network). For each
established connection, the request
-
er’s connection information and the
destination are stored so that the
answer can be assigned to the right
requester. In the public IP-based net-
work, the private network address of
the requester is not known. NAT is
required in iPv4 networks due to the
existing shortage of iPv4 addresses.
Private networks receive just one
public network address instead of
several. There are two different NAT
methods. NAT is also used within
an IP-based network for the internal
separation or connection of several
private networks with different net
-
work address spaces.
