lan9420 Standard Microsystems Corp., lan9420 Datasheet - Page 62

• Manufacturer Part Number: lan9420
• Description: Lan9420/lan9420i Single-chip Ethernet Controller With Hp Auto-mdix Support And Pci Interface
• Manufacturer: Standard Microsystems Corp.

Revision 1.1 (03-31-08)
DST
0
{DSAP, SSAP, CTRL, OUI[23:16]}
The RXCOE supports a maximum of two VLAN tags. If there are more than two VLAN tags, the VLAN
protocol identifier for the third tag is treated as an Ethernet type field. The checksum calculation will
begin immediately after the type field.
DST
0
1
DST
0
SRC
1
Figure 3.24 Ethernet Frame with multiple VLAN Tags and SNAP Header
{DSAP, SSAP, CTRL,
SRC
2
{DSAP, SSAP, CTRL,
1
Figure 3.22 Ethernet Frame with Length Field and SNAP Header
2
OUI[23:16]}
SRC
Figure 3.23 Ethernet Frame with VLAN Tag and SNAP Header
8
1
0
0
4
OUI[23:16]}
2
V
I
D
8
1
0
0
3
8
1
0
0
V
I
D
5
L
e
n
3
L
e
n
V
I
D
4
S
N
A
P
0
L
e
n
S
N
A
P
0
6
4
S
N
A
P
0
5
S
N
A
P
1
S
N
A
P
1
7
5
S
N
A
P
1
6
8
Single-Chip Ethernet Controller with HP Auto-MDIX Support and PCI Interface
{OUI[15:0], PID[15:0]}
DATASHEET
{OUI[15:0], PID[15:0]}
{OUI[15:0], PID[15:0]}
62
Calculate Checksum
Calculate Checksum
Calculate Checksum
L3 Packet
L3 Packet
L3 Packet
SMSC LAN9420/LAN9420i
F
C
S
C
F
S
F
C
S
Datasheet