Transition Mechanisms

1.       Dual Stack - support both Internet Protocol in parallel within one network

a.       Dual Stack in a device means Both IPv4 and IPv6 stacks enabled

b.      Application(IPv4 and IPv6) can talk both

c.       Is a network which all of the nodes are both IPv4 and IPv6 enabled.

d.      Dual Stack network are capable of processing IPv4 and IPv6 traffic simultaneously(Good interoperability)

e.      Is one of several solutions for migrating from IPv4 to IPv6, but it is also one of the most expensive

f.        Easy way to deploy, Easy to use,  flexible, bring up 2 protocol in parallel with first

g.   It will increase the system resources, and decrease the performance of devices.

       2.       Tunnels - encapsulates one protocol within another (e.g. IPv6 in IPv4, IPv4 in IPv6)

·         Used to implement the interconnection between the isolated IPv6 network distributed in an IPv4 network or isolated IPv4 network distributed in an IPv6 network.

a.       Enable IPv6 islands or individual nodes to communicate over an IPv4 network

b.      Allow IPv6 traffic to be carried across an IPv4 network

c.       Two modes of tunneling support are possible:

                                                               i.       Configured (Manual) Tunneling

1.       Simple to deploy, allow transport of IPv6 packets over IPv4 network

2.       Cost effective of obtaining IPv6 connectivity

                                                             ii.      Automatic Tunneling

1.       IPv4 compatible IPv6

2.       IPv6 over IPv4

3.       IPv6 to IPv4 – uses 6to4 relay to connect to an IPv6 network without the need to configure explicit tunnels This is often hosted by a third party outside of enterprise and uses IPv6 address

4.       ISATAP(Intra-Site Automatic Tunnel Addressing Protocol) – provide for a client to client tunnel or client to router tunnel and requires no manual configuration

5.       Tunnel Broker – TSP Tunnel Broker over TCP.UDP, IPv4 and IPv6. Uses Tunnel Broker in the server or router to traverse NATs

6.       Teredo (developed by Microsoft proponent) – used for connection to the IPv4 Internet. This protocol will make a hole in Firewall and will allow traversal of Network Address Translators (NAT). Teredo is more commonly found in home networks rather enterprise networks

3.       Translation – translates packets between protocols (e.g. IPv6 to IPv4)

a.       Enable IPv4 only network & nodes to communicate with IPv6 only network & nodes

b.      Translation at transport layer or IP layer, & application layer gateways

c.       IPv6 stateless address auto-configuration

·         Used for interworking between IPv6 only network and IPv4 only network.

·         Translation devices are located on the border of two network. They need to translate corresponding field of IP header and translate the IP address carried in the packet body. The device translating IP addresses in packet is called an application level gateway(ALG)