NEC Univerge sv8500 Manual page 196

3.4 Virtual LAN (VLAN)
3.4.1 General
The implementation of Virtual LANs (VLANs) divides voice and data network into different segments at
Layer2. The system uses Tagged VLAN, which conforms to IEEE 802.1q. To identify VLAN frame, a unique
ID called VLAN-ID (VID) must be tagged for each packet sent from the IP terminals and the PH/IPPAD Cards.
To tag a VID to packets sent from the PH/IPPAD Cards, the ALIDL is used. Packets from the DtermIP can be
tagged by key operations on the terminal. User priority can also be used, by which you can give higher priority
to voice packets to provide high speech quality. User priority bits conform to IEEE 802.1p. The following figure
shows a MAC frame tagged with a VLAN tag.
VLAN for Voice
User Priority = 5
Voice Packet
Data Packet
Tagged VLAN (conforms to IEEE 802.1q)
To use this feature, Switch must support Tagged VLAN. This feature is not supported by Internal PH. (For In-
ternal PH, use Port VLAN.)
CHAPTER 2
Virtual LAN (VLAN)
SW
VLAN for Data
User Priority = 0
Tag Control
Information (TCI)
Priority Control
VOL.1-136
IP-RELATED BASIC FEATURE PROGRAMMING
MAC Frame
with VLAN
Destination
MAC address
Source
MAC address
TPID: 0x8100
TCI
Length
Router
Data Field
MTU = 1500
FCS
TPID (fixed 0x8100)
User Priority CFI
(0-7) (1) (0-4095)
2 bytes
VLAN-ID (VID)
Tag VLAN