Planet Networking & Communication GS-5220-24P4X User Manual page 381

UDP provides two services not provided by the IP layer. It provides port numbers to help distinguish different user
requests and, optionally, a checksum capability to verify that the data arrived intact.
Common network applications that use UDP include the Domain Name System (DNS), streaming media applications
such as IPTV, Voice over IP (VoIP), and Trivial File Transfer Protocol (TFTP).
UPnP
UPnP is an acronym for Universal Plug and Play. The goals of UPnP are to allow devices to connect seamlessly and to
simplify the implementation of networks in the home (data sharing, communications, and entertainment) and in
corporate environments for simplified installation of computer components
User Priority
User Priority is a 3-bit field storing the priority level for the 802.1Q frame.
V
VLAN
A method to restrict communication between switch ports. VLANs can be used for the following applications:
VLAN unaware switching: This is the default configuration. All ports are VLAN unaware with Port VLAN ID 1 and
members of VLAN 1. This means that MAC addresses are learned in VLAN 1, and the switch does not remove or
insert VLAN tags.
VLAN aware switching: This is based on the IEEE 802.1Q standard. All ports are VLAN aware. Ports connected to
VLAN aware switches are members of multiple VLANs and transmit tagged frames. Other ports are members of one
VLAN, set up with this Port VLAN ID, and transmit untagged frames.
Provider switching: This is also known as Q-in-Q switching. Ports connected to subscribers are VLAN unaware,
members of one VLAN, and set up with this unique Port VLAN ID. Ports connected to the service provider are VLAN
aware, members of multiple VLANs, and set up to tag all frames. Untagged frames received on a subscriber port are
forwarded to the provider port with a single VLAN tag. Tagged frames received on a subscriber port are forwarded to
the provider port with a double VLAN tag.
VLAN ID
VLAN ID is a 12-bit field specifying the VLAN to which the frame belongs.
Voice VLAN
Voice VLAN is VLAN configured specially for voice traffic. By adding the ports with voice devices attached to voice
VLAN, we can perform QoS-related configuration for voice data, ensuring the transmission priority of voice traffic and
voice quality.
User's Manual of GS-5220 Ultra PoE & PoE+ Series
381