W90N740CD WINBOND [Winbond], W90N740CD Datasheet - Page 113

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

6.6.2.8. EXMACM, INMACM, LSMACxM, RSMACxM
EXMACL, INMACL, LSMACxL, RSMACxL
NAT Masquerading IP Address Registers (MASADx) (x : 15 ~ 0)
NAT Masquerading Port Number Registers (MASPNx) (x : 15 ~ 0)
Local Station IP Address Registers (LSADx) (x : 15 ~ 0)
Local Station Port Number Registers (LSPNx) (x : 15 ~ 0)
The {MASADx, MASPNx} is represented for the outside IP address and the port number.
The {LSADx, LSPNx} is represented for the internal IP address and the port number.
A private network is set up with its own public IP address (MASADx) and port number (MASPNx) for
external access. It means that when a local station wants to sent a packet outside via the NAT
module, the packet is transmitted to external MAC port with its source address and source port
number replaced by MASADx and MASPNx.
On the other hand, when the external MAC receive packet, its destination address and destination
port number is compared. If the result is hit, then its destination address and destination port number
are be replaced by LSADx and LSPNx, and the packet is transmitted to local MAC.
31
23
15
31
23
15
7
7
30
22
14
30
22
14
6
6
29
21
13
29
21
13
5
5
Address Byte 6 (Most Significant Byte)
Destination Address Byte 2
Destination Address Byte 1
28
20
12
28
20
12
Address Byte 5
Address Byte 4
Address Byte 3
4
4
Reserved
Reserved
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W90N740CD/W90N740CDG
27
19
11
27
19
11
3
3
26
18
10
26
18
10
2
2
25
17
25
17
9
1
9
1
24
16
24
16
8
0
8
0