Basic ideas
Before the fundamental NAT method of NE40E core router is introduced, familiarise yourself with the subsequent concepts:
NAT service board: could be a physical board that has the NAT capability.
NAT address pool: is associate address pool accustomed manage NAT address resources.
NAT traffic diversion: uses diversion rules to spot user packets that require to be translated exploitation NAT and direct the packets to a NAT service board for NAT translation.
NAT instance: could be a service configuration unit that's sure to NAT service boards, address pools, and different NAT attributes.
Basic method
The implementation varies in step with readying modes, address pool varieties, and traffic diversion modes. the subsequent sections describe NAT classification, NAT address pool and its conversion basis, and NAT port allocation.
- After receiving packets, the device checks whether or not NAT is needed.
If the user packets don't match the ACL, the device forwards the packet supported the common packet forwarding method.
- The NE40E diverts the user packets to the NAT service board sure to the NAT instance for translation.
- The NE40E selects the information processing address and port variety from the address pool and port vary sure to the NAT instance to interchange the prevailing supply information processing address and port variety within the user packet to implement NAT.
- After the interpretation, the user packets area unit forwarded to following hop supported the regular forwarding method.
Reverse NAT Conversion
- After receiving a packet, the NE40E determines whether or not to perform reverse NAT translation.
The NE40E filters the user packets in FIB traffic diversion mode and diverts user packets that require to be translated to a NAT service board for translation.
If the destination address within the user packet matches a NAT address pool route within the FIB table, the NE40E performs reverse NAT.
If the destination address of a user packet matches a route of another sort, the NE40E forwards the packet supported the regular packet forwarding method.
- The NAT service board performs reverse translation on user packets supported NAT mapping entries. The destination information processing address and port variety in every user packet area unit replaced with a personal information processing address and a port variety.
- After reverse NAT is performed, user packets area unit forwarded to following hop supported the regular forwarding method.
https://support.huawei.com/enterprise/en/doc/EDOC1100092121
