Planet WGSW-24040 User Manual page 325

decoded into 64 possibilities, and the singular code that results is compared against the corresponding bit in the IPv4
ToS priority control bit (0~63).
TLV
A LLDP frame can contain multiple pieces of information. Each of these pieces of information is known as TLV (TLV is
short for "Type Length Value").
U
UDP
UDP is an acronym for User Datagram Protocol. It is a communications protocol that uses the Internet Protocol (IP) to
exchange the messages between computers.
UDP is an alternative to the Transmission Control Protocol (TCP) that uses the Internet Protocol (IP). Unlike TCP, UDP
does not provide the service of dividing a message into packet datagrams, and UDP doesn't provide reassembling and
sequencing of the packets. This means that the application program that uses UDP must be able to make sure that the
entire message has arrived and is in the right order. Network applications that want to save processing time because
they have very small data units to exchange may prefer UDP to TCP.
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).
User Priority
User Priority is a 3-bit field storing the priority level for the 802.1Q frame.
V
VLAN
Virtual LAN. 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.
User's Manual of WGSW-24040 / WGSW-24040R
325
SGSW-24040 / SGSW-24040R