encapsulation
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... prefix to any site that currently has at least one globally
unique IPv4 address, and specifies an encapsulation mechanism for
transmitting IPv6 packets ...
... Encapsulation in IPv4 ...
... IPv6 packets from a 6to4 site are encapsulated in IPv4 packets when
they leave the site via its external IPv4 ...
... IPv4 Time to Live will be set as normal [RFC791], as will the
encapsulated IPv6 hop limit [IPV6]. Other considerations are as
...
... interface performing 6to4
encapsulation would, if needed, be formed as described in Section 3.7
of [MECH]. However, no scenario is known in which such an address ...
...
When an outgoing packet reaches the 6to4 router, it is encapsulated
as defined in Section 3, according to the additional sending rule
defined in Section 5.3. Incoming packets ...
... model, there are believed to be no particular scaling issues with the
basic 6to4 mechanism apart from encapsulation overhead.
Specifically, it introduces no new entries in IPv4 routing ...
... relay router should not attempt to serve more sites than any other
transit router, allowing for the encapsulation overhead.
...
... part in the 6to4 mechanism, and 6to4 encapsulation and decapsulation
can only take place at the outermost NAT ...
... system will be returned to the 6to4 router that generated a
encapsulated 2002:: packet. However, this router will often be
unable to return an ICMPv6 ...
... plausibility check is whether the encapsulating IPv4 address is
consistent with the encapsulated 2002:: address. If this check is
applied, exceptions to it must be configured to admit traffic ...