Which two technologies can encapsulate an IPv6 payload in an IPv4 packet for transmission across a network? (Choose Two)
正解:D,E
Explanation/Reference: Explanation: The Network Address Translator - Protocol Translator (NAT-PT) defines a set of network-layer translation mechanisms designed to allow nodes that only support IPv4 to communicate with nodes that only support IPv6, during the transition to the use of IPv6 in the Internet. NAT-PT provides IPv4/IPv6 protocol translation. It resides within an IP router, situated at the boundary of an IPv4 network and an IPv6 network. By installing NAT-PT between an IPv4 and IPv6 network, all IPv4 users are given access to the IPv6 network without modification in the local IPv4-hosts (and vice versa). Equally, all hosts on the IPv6 network are given access to the IPv4 hosts without modification to the local IPv6-hosts. This is accomplished with a pool of IPv4 addresses for assignment to IPv6 nodes on a dynamic basis as sessions are initiated across IPv4-IPv6 boundaries Reference: http://www.ietf.org/rfc/rfc4966.txt http://www.cisco.com/en/US/prod/collateral/iosswrel/ps8802/ps6969/ps1835/ prod_white_paper09186a008011ff51_ps6640_Products_White_Paper.html ISATAP tunneling (Intra-Site Automatic Tunnel Addressing Protocol): is a mechanism for transmitting IPv6 packets over IPv4 network. The word "automatic" means that once an ISATAP server/router has been set up, only the clients must be configured to connect to it.