Aft Internal Server; Aft Translation Process; Ipv6-Initiated Communication - HPE FlexNetwork HSR6800 Configuration Manual

General prefix translation
A general prefix is an IPv6 address prefix used to construct an IPv6 address representing an IPv4
node in an IPv6 network. The length of a general prefix can be 32, 40, 48, 56, 64, or 96.
As shown in
IPv4 address is embedded as a whole into an IPv6 address.
Figure 149 General prefix based IPv6 address format
AFT uses a general prefix for IPv6-to-IPv4 source and destination address translation. If a source or
destination IPv6 address matches the general prefix, AFT translates it to the embedded IPv4
address.
A general prefix cannot be on the same subnet as any interface on the device.

AFT internal server

AFT internal server maps an IPv4 address and port number to the IPv6 address and port number of
an IPv6 internal server. It allows the IPv6 internal server to provide services to IPv4 hosts.

AFT translation process

The address translation differs for IPv6-initiated communication and IPv4-initiated communication.

IPv6-initiated communication

As shown in
follows:
1. Upon receiving a packet from the IPv6 host, AFT compares the packet with IPv6-to-IPv4
destination address translation policies.
If a matching policy is found, AFT translates the destination IPv6 address according to the
policy.
If no matching policy is found, AFT does not process the packet.
2. AFT performs pre-lookup to determine the output interface for the translated packet. PBR is not
used for the pre-lookup.
If a matching route is found, the process goes to step 3.
If no matching route is found, AFT discards the packet.
3. AFT compares the source IPv6 address of the packet with IPv6-to-IPv4 source address
translation policies.
Figure 149, a general prefix based IPv6 address does not have reserved bits, and an
Figure 150, when the IPv6 host initiates access to the IPv4 host, AFT operates as
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