Your company has implemented IPv6 addresses and routing on every host, server, and router. Recently, your company acquired another company that has an IPv4 addressing scheme for its entire network. The acquired company’s network does not have any support for IPv6. You need to devise a method so that the IPv6 hosts in your company can seamlessly communicate with the IPv4 hosts of the acquired company’s network. You do not want to install any additional routers, and you want minimum configuration changes on the networks.
Which of the following is the best method to allow communication between the IPv4 and IPv6 hosts?
A. Embedding IPv6 packets into IPv4 packets
B. Translating IPv4 addresses to and from IPv6 addresses
C. Configuring IPv6 on the hosts and routers in the IPv4 network
D. ConfiguringIPv4 on the hosts and routers in the IPv6 network
Explanation:
Translating IPv4 addresses to and from IPv6 addresses is the best method to allow communication between the IPv4 and IPv6 hosts. This translation of IPv4 and IPv6 addresses is known as Network Address Translation-Protocol Translation (NAT-PT). NAT-PT is a technique available for deploying IPv6 and IPv4 addresses in a unified network. With NAT-PT, the network requires fewer modifications and software for the IPv4 and IPv6 hosts. Additionally, it provides easy and quick interoperability between the IPv4 and IPv6 hosts.
NAT-PT is configured on one of the routers on the border of the IPv4 and IPv6 networks. Whenever an IPv4 packet intended for a host in the IPv6 network is received by the NAT-PT router, the router applies NAT-PT on the packet and translates all the headers in the IPv4 headers. In addition, it translates the IPv4 source and destination addresses to IPv6 source and destination addresses. The IPv6 packet is then set by the NAT-PT router to the intended IPv6 host. The NAT-PT router performs the reverse translation when an IPv6 host sends a packet to an IPv4 host.
Embedding IPv6 packets into IPv4 packets is not the best method to allow communication between the IPv4 and IPv6 hosts. When IPv6 packets are embedded inside IPv4 packets, the process is referred to as tunneling. Tunneling is appropriate when two IPv6 networks are separated by an IPv4 network. When an IPv6 host of one network sends an IPv6 packet destined for a host on the other IPv6 network, an IPv4 tunnel is created between the two IPv6 networks. The IPv6 packet is then embedded into an IPv4 packet that traverses through the IPv4 tunnel to reach the intended IPv6 host, where the embedded packet is extracted by the recipient. In this scenario, a single IPv6 network is available; hence, a tunnel cannot be formed.
Configuring IPv6 on the hosts and routers in the IPv4 network, or configuring IPv4 on the hosts and routers in the IPv6 network, are not the best methods to allow communication between the IPv4 and IPv6 hosts. Each of these two methods is cumbersome and not the most efficient for providing interoperability between IPv4 and IPv6 in this case. Furthermore, the IPv4 hosts on the acquired company’s network do not support IPv6 as stated.
Objective:
Network Principles
Sub-Objective:
Recognize proposed changes to the network
References:
Cisco NAT Configuration Guide, Release 15M&T > NAT-PT for IPv6