RFC 4891:Using IPsec to Secure IPv6-in-IPv4 Tunnel...
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IP interface


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... The use of the word "interface" or the phrase "IP interface" refers to the IPv6 interface ...


... SPDs": some implementations model the tunnel mode SA as an IP interface. In this case, an IPsec tunnel interface ...
... 2. "Specific SPDs": some implementations do not model the tunnel mode SA as an IP interface. Traffic selection is based on specific SPD ...



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