G.shdsl Router User Manual
means that some other device, either the originator of the frame or a VLAN-aware bridge, has
mapped this frame into a VLAN and has inserted the appropriate VID.
The following figure shows the difference between a untagged frame and VLAN tagged frame,
where the Tag Protocol Identifier (TPID) is of 0x8100 and it identifies the frame as a tagged frame.
The Tag Control Information (TCI) consists of the following elements: 1) User priority allows the
tagged frame to carry user priority information across bridged LANs in which individual LAN
segments may be unable to signal priority information (e.g., 802.3/Ethernet segments). 2) The
Canonical Format Indicator (CFI) is used to signal the presence or absence of a Routing
Information Field (RIF) field, and, in combination with the Non-canonical Format Indicator (NCFI)
carried in the RIF, to signal the bit order of address information carried in the encapsulated frame.
3) The VID uniquely identifies the VLAN to which the frame belongs.
Applications
WAN
LAN1
LAN2
LAN3
LAN4
Group 1
Group 2
Group 3
Port-based VLAN
1
8
PWR
OK
WIC0
ACT/CH0
ACT/CH1
WIC0
ACT/CH0
ACT/CH1
ETH
ACT
COL
PWR
OK
WIC0
ACT/CH0
AC T/CH1
WIC0
ACT/CH0
ACT/CH 1
ETH
AC T
COL
SHDSL connection
with 2PVC
LAN1
LAN1
LAN2
LAN2
LAN3
LAN3
LAN4
LAN4
CO
CPE
SERVER
SERVER
1 2
3
4 5
6
7 8
9
*
8
#
1 2
3
4 5
6
7 8
9
*
8
#
VoIP
VoIP
802.1q VLAN
12