MEDIATEK Ralink MT7620 - Page 240

PGMT7620_V.1.0_040503
Page 240 of 523
MT7620 PROGRAMMING GUIDE
Integrated 802.11n MAC/BBP and 2.4 GHz RF/FEM Router-on-a-Chip
2.20.3.3 Unicast Frames
FTAG
DA
Type
Description
UC
The 1st bit of MSB is 1’b0
-
Unicast Frames
ARP
FF-FF-FF-FF-FF-FF
08-06
ARP Request Frames
-
08-06
ARP Reply Frames
RARP
FF-FF-FF-FF-FF-FF
80-35
RARP Request Frames
-
80-35
RARP Reply Frames
2.20.4 Switch L2/L3 Address Table
The switch has a 2 K address table built in for packet look-up forwarding. All the entries can be shared and
mixed by L2 MAC address or L3 IP address according to “TYPE” definition. When the entry is regarded as a
MAC address table, it is used to forward packets by L2 DA and learn packets by L2 SA. When the entry is
regarded as a DIP address table, it is used to process IGMP/MLD snooping. To support IGMPv3/MLDv2, a SIP
entry is added to search the Source IP list after DIP look-up.
2.20.4.1 MAC address table
Bytes
Bits
Name
Description
7:0
11:0
CVID
Customer VID [11:0]
Customer VLAN ID is learned automatically from VLAN tag or port-based
register PPBV#.PORT_VID.
14:12
FID
Filter ID[2:0]
Filter ID is learned automatically from VLAN Table. 0 is the default value if
VLAN Table is not applicable.
15
IVL
Independent VID Learning
IVL is learned automatically from VLAN Table. 0 is the default value if VLAN
Table is not applicable.
63:16
ADDRESS
MAC Address[47:0]
48-bit MAC Physical Address is searched by Destination MAC Address and
learned from Source MAC Address.
3:0
1:0
TYPE
Layer2/Layer3 Address Entry Type
2’b00: MAC Address Entry
2’b01: DIP Address Entry.
2’b10: Source IP Address Table (See Table 3-28)
2’b11: Reserved
3:2
STATUS
Address Entry Live Status
2’b00: Entry is empty
2’b01: Entry is dynamic and valid
2’b10: Reserved
2’b11: Entry is static and cannot be aged out or changed by hardware.
11:4
PORT /
FILTER
Destination Port Map
Bit4 : Port 0
…
Bit11: Port 7
NOTE: Frame dropped by DA Address through PORT=6’b0.