Nat-Pt Mechanism; Implementing Nat-Pt - 3Com MSR 50 Series Configuration Manual

680 C 47: NAT-PT C
HAPTER

NAT-PT Mechanism

Implementing NAT-PT

ONFIGURATION
"NAT-PT Mechanism" on page 680
■
"Implementing NAT-PT" on page 680
■
There are three NAT-PT mechanisms to realize the translation between IPv4 and
IPv6 addresses: "Static NAT-PT mapping" on page
mapping" on page
Static NAT-PT mapping
Static NAT-PT mapping means that translation between IPv6 and IPv4 addresses is
realized by using the one-to-one relationship manually configured between IPv6
addresses and IPv4 addresses.
Dynamic NAT-PT mapping
Different from static mapping, dynamic mapping does not provide the one-to-one
relationship between IPv6 addresses and IPv4 addresses.
For a dynamic mapping, an address pool needs to be created first. After that, an
available address is assigned from the address pool to accomplish the mapping
between one IPv6 address and one IPv4 address.
NAPT-PT
Network address port translation - protocol translation (NAPT-PT) realizes the IPv6
to IPv4 translation for TCP/UDP port numbers based on dynamic IP address
translation. With NAPT-PT, different IPv6 addresses can correspond to one IPv4
address. Different IPv6 hosts are distinguished by different port numbers so that
these IPv6 hosts can share one IPv4 address to accomplish the address translation.
Session initiated by an IPv6 host:
Figure 201 NAT-PT implementation (session initiated by an IPv6 host)
IPv 4 : 8 . 0 . 0 . 2
IPv 6 : 3001 : 2
IPv 4 host
Source : 8 . 0 . 0 . 5
Destination : 8 . 0 . 0 . 2
Source : 8 . 0 . 0 . 2
Destination : 8 . 0 . 0 . 5
The NAT-PT implementation process for a session initiated by an IPv6 host is as
follows:
1 A packet from an IPv6 host to an IPv4 host reaches the NAT-PT device. The NAT-PT
device translates the source IPv6 address of the packet into an IPv4 address
according to the static or dynamic IPv6-to-IPv4 mappings.
2 The NAT-PT device translates the destination address of the packet into an IPv4
address according to the IPv4-to-IPv6 mapping, if configured, on the IPv4 network
side. Without any mapping configured on the IPv4 network side, if the least
significant 32 bits of the destination IPv6 address in the packet can be directly
680, and "NAPT-PT" on page
NAT - PT
Source : 3001 :: 5
Destination : 3001 :: 2
Source : 3001 :: 2
Destination : 3001 :: 5
680, "Dynamic NAT-PT
680.
IPv 6 : 3001 :: 5
IPv 4 : 8 . 0 . 0 . 5
IPv 6 host