Stateful stateful and stateless stateless address translation

NAT64 belongs to stateful address translation technology, IVI is a stateless address translation technology, this blog simply summarizes the status (stateful) and stateless (stateless) address conversion features.

Features of stateful address translation: (for example, IPV6 user access ipv4-only server in NAT64 technology)

Maintain the conversion state of the IPv4 Addr/port and IPv6 addr/port on Xlat (the mapping between the IPV6 user address and the converted IPv4 addr/port)

Configure the address translation rules (mapping algorithm) on the Xlat (ipv4-only the mapping algorithm between the server address and DNS64 synthesized IPv6 address)

Support only IPV6 to initiate access

A IPV4 server for IPV6 Access can assign a private network address, or it can assign a public network address.

IPV6 users who initiate access can assign arbitrary IPV6 addresses

Cannot assign a constant unique IPV4 address for a IPV6 node

The characteristics of stateless address conversion: (Take IVI technology as an example)

Configure address translation rules (mapping algorithm) on Xlat without maintaining Ipv4/ipv6 conversion state

Support IPV6 initiates IPV4 Access also supports IPV4 initiates IPV6 visit

Support E2E Address Transparency

IPV4 can only access a subset of IPV6 addresses because the IPV6 address space and the IPV4 address space are not known

The IPV6 address to convert is a IPV6 address with a specific prefix

The IPV4 address to convert does not recommend private network IPV4 address

The more popular explanation is that, stateless address translation, IPV4 address and IPV6 address are closely related, through some mapping algorithm only determined that the same user any time conversion results are the same, xlat do not need to record any session information (mapping table), Only the mapping algorithm needs to be maintained. When stateful address translation is present, there is no relationship between the IPV4 address and the IPV6 address, and it is necessary to map the available addresses and ports according to the current use state of IPv4 pool, and the same user will get different results at different times, Xlat need to record the session information of the user conversion ( mapping table).

In short: If the Xlat need to record the mapping before and after the address conversion is stateful, otherwise stateless.

Original link: http://blog.csdn.net/hanlijin/article/details/17047719