496
U
UDP
UDP is an acronym for
U
ser
D
atagram
P
rotocol. 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).
UPnP
UPnP is an acronym for
U
niversal
P
lug and
P
lay. 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
Virtual LAN is 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
Summary of Contents for IFS NS3550-24T/4S
Page 1: ...P N 1072569 REV 00 05 ISS 11OCT12 IFS NS3550 24T 4S User Manual ...
Page 37: ...User s Manual of NS3550 24T 4S 37 ...
Page 96: ...96 Figure 4 4 6 Port Mirror Configuration Page Screenshot ...
Page 127: ...User s Manual of NS3550 24T 4S 127 Figure 4 6 10 Port 1 Port 6 VLAN Configuration ...
Page 184: ...184 Figure 4 9 14 Voice VLAN Configuration Page Screenshot ...
Page 204: ...204 Figure 4 11 4 Network Access Server Configuration Page Screenshot ...
Page 234: ...234 Figure 4 12 1 Port Limit Control Configuration Overview Page Screenshot ...
Page 250: ...250 Click to undo any changes made locally and revert to previously saved values ...
Page 297: ...User s Manual of NS3550 24T 4S 297 ...
Page 388: ...388 Example Show RADIUS statistics SWITCH security aaa statistics ...
Page 410: ...410 Parameters vid VLAN ID 1 4095 Default Setting disable ...