W90N740CD WINBOND [Winbond], W90N740CD Datasheet - Page 69

• Manufacturer Part Number: W90N740CD
• Description: 32-Bit ARM7TDMI-Based Micro-Controller
• Manufacturer: WINBOND [Winbond]

These bits records error status if NAT processing error is occurred and are wrote by NATA.
IP Header Length: TCP/UDP header location offset
The offset value lets the NAT accelerator to identify the starting address of TCP or UDP header, which
is used for NAT to parsing port data. The value is valid if Hit is set.
Hit Entry Number: the entry number hit with the input address
The value indicates which entry is hit to let NAT accelerator to take corresponding data. The value is
valid if Hit is set.
PPPCaps: PPPoE datagram encapsulated
The value is 1 if PPP encapsulation is used (8 bits protocol field), and 0 if encapsulation is not used
(16 bits protocol field).
PPPoE: PPPoE protocol
The value is 1 if the packet takes PPPoE protocol instead of IP protocol. The value is 0 if the packet
takes IP protocol.
UCKS: UDP protocol with skip checksum replacement
The value is 1 if the packet takes UDP protocol, and its checksum is zero. The NAT accelerator will
skip the checksum replacement procedure.
UDP: apply UDP protocol
It tell NAT engine to apply UDP protocol. The value is 1 if the packet takes UDP protocol, and 0 if the
packet takes non-UDP protocol. The value is valid if Hit is set.
TCP: apply TCP protocol
It tell NAT engine to apply TCP protocol. The value is 1 if the packet takes TCP protocol, and 0 if the
packet takes non-TCP protocol. The value is valid if Hit is set.
L/W: hit port; the value is 1 if internal (LAN) port gets hit, and 0 if external (WAN) port is hit
The S/W program must specify LAN port and WAN port with the two EMCs. For example, EMC 0 is
connected to WAN port, and EMC 1 is connected to LAN port. If NAT is enabled, EMC 0 is connected to
external port for {MA, MP} comparison, and EMC 1 is connected to internal port for {LA, LP} comparison.
The L/W value is 1 if the hit port is internal port, and 0 if the hit port is external port. The value is valid if
Hit is set.
Hit: current packet is hit with NAT entry table
The value is 1 if current packet IP/port is in the entry list. If NAT is disabled, the bit is reserved.
(1) UCK_Err: TCP = 1 and UCKS = 1
(2) TU_Err: TCP = 1 and UDP = 1
(3) NH_Err: No hit error
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W90N740CD/W90N740CDG