MEDIATEK Ralink MT7620 - Page 245

PGMT7620_V.1.0_040503
Page 245 of 523
MT7620 PROGRAMMING GUIDE
Integrated 802.11n MAC/BBP and 2.4 GHz RF/FEM Router-on-a-Chip
Bits
Name
Description
59:48
S_TAG2
(2) Service Tag Index
b[50:48]: Port 4 STAG index
b[53:51]: Port 5 STAG index
b[56:54]: Port 6 STAG index
b[59:57]: Port 7 STAG index
2.20.5.2 VLAN tagging
The switch can support customer and service VLAN tags (inner/ outer VLAN tags) inside a frame. When a frame
is incoming, its VLAN tags will be stripped by one or two based on different ingress port attributes –
PVC.VLAN_ATTR. Similarly, their tags will be used for VLAN table search or MAC table search according to the
incoming port attribute.
Finally, the per-port egress tag control will be carried on the TX_CTRL side. The transmitted frame will follow
the egress control and carry the processed VLAN tags - VID0 (service tag) and VID1 (customer tag).
2.20.5.3 User port
Stack
Port
VID #
DASA
E/LData
DASAVID #E/LData
DASAE/LData
DASAE/LData
PVID #
VID 1
VID 1
RX_CTRL PARSER
CVID#MAC# PORT
CVID#
MEMBER
CVID#
MEMBER
CVID#
MEMBER
CVID# MEMBER
SVID#
SVID#
SVID#
SVID#
MAC Table
VLAN Table
VID #
DASAE/L
VID 1
CVID#MAC# PORT
CVID#
MAC#
PORT
CVID#MAC# PORT
SVID #
VID 0
PVID #
DASAE/LData
VID 1
SVID #
VID 0
Look-up Engine
DASAE/LData
DASAE/LData
TX_CTRL
SVID#
DASAVID #E/LData
VID #
SA Learning
Swap
Tag / Consistent for tagged
Untag / Consistent for untagged
DASAE/LData (P)VID#
DASAE/LData (P)VID#
Stack
SVID#
0 to N-1 VLAN
tagged
Untagged or
priority-tagged
VID1 VID0
VID0
VID1
NOTE:
1. etag_ctrl(bit[1]-VID1,bit[0]-
VID0) --
00: Untag
10: Tag
01: Swap
11: Stack
2. Consistent Tag Format attribute
NOTE:
1. RX_CTRL remove 1 VLAN tag on L2 space (at most 3 tags)
2. Incoming frame attribute -
‘untagged’, ‘priority-tagged’, ‘tagged’
Data
Not applicable for
translation