Appendix C:
Glossary
NGSME24G4S User Manual | 381
MVR
Multicast VLAN Registration (MVR) is a protocol for Layer 2 (IP)-networks that enables
multicast-traffic from a source VLAN to be shared with subscriber-VLANs.
The main reason for using MVR is to save bandwidth by preventing duplicate multicast
streams being sent in the core network, instead the stream(s) are received on the
MVR-VLAN and forwarded to the VLANs where hosts have requested it/them (Wikipedia).
N
NTP
NTP is an acronym for
N
etwork
T
ime
P
rotocol, a network protocol for synchronizing the
clocks of computer systems. NTP uses UDP (datagrams) as transport layer.
O
Optional
TLVs.
A LLDP frame contains multiple TLVs
For some TLVs it is configurable if the switch shall include the TLV in the LLDP frame.
These TLVs are known as optional TLVs. If an optional TLVs is disabled the corresponding
information is not included in the LLDP frame.
OUI
OUI is the organizationally unique identifier. An OUI address is a globally unique identifier
assigned to a vendor by IEEE. You can determine which vendor a device belongs to
according to the OUI address which forms the first 24 bits of a MAC address.
P
PCP
PCP is an acronym for
P
riority
C
ode
P
oint. It is a 3-bit field storing the priority level for the
802.1Q frame. It is also known as User Priority.
PD
PD is an acronym for
P
owered
D
evice. In a PoE system the power is delivered from a PSE
(power sourcing equipment) to a remote device. The remote device is called a PD.
PHY
PHY is an abbreviation for Physical Interface Transceiver and is the device that implement
the Ethernet physical layer (IEEE-802.3).
