IPv6: Not When but How?

Over the last 10 years, there have been a lot of discussions about the depletion of IPv4 addresses. With development of the IPv6 standards, general consensus is that the Internet will eventually transition to IPv6. The real question has been “When will this transition take place?”

For Communication Service Providers (CSP), increases in data usage and IP devices have caused industry standard’s bodies (such as 3GPP, TiSpan, 3GPP2 and CDG) to incorporate IPv6 in their high speed network architectures. This has caused CSP’s to include transition to IPv6 as part of their 4G and advanced network rollouts. The challenge is that with the majority of the Internet still being on IPv4, how is the best way to still give subscribers access to the content that they want and demand. So for the CSP’s, the question now is not when but how to transition to IPv6.

There are several articles, blogs and discussions on the Internet about the different methods of transitioning to IPv6. Instead of re-hashing this information, I want to concentrate on the pros vs. cons of a few of the more prevalent methods.

Dual Stack
- What is it?
  Dual stack is where a single system supports both IPv6 and IPv4 simultaneously. This is usually accomplished by both a hardware and software on the system.
- PROS
  This is a quick method to transition to a new IPv6 network while still supporting traffic on an IPv4 network.
- CONS
  This is extremely costly and can significantly impact performance of an individual system.
DS –Lite
- What is it?
  DS – Lite requires the deployment of an IPv6 network and encapsulates IPv4 traffic in an IPv6 wrapper. This method was specifically designed for Cable networks interactions with set top boxes.
- PROS
  This method allows the deployment of IPv6 across the network and allows for IPv4 deployed protocols and applications that cannot use NAT to be integrated.
- CONS
  DS-Lite provides a significant overhead and is not all encompassing. Other solutions need to be incorporated in order to support IPv6 native protocols and traffic.
6RD
- What is it?
  6RD uses pre-existing tunnels on an IPv4 network to transport IPv6 traffic.
- PROS
  This method is a fast way to support IPv6 traffic.
- CONS
  This does not deploy an IPv6 network at all. All the problems of IPv6 transition sill exist.
Gateway and DNS64/NAT64
- What is it?
  This method deploys a gateway to translate IPv4 traffic to IPv6, and back, and uses DNS64 to translate IPv4 records (A records) to IPv6 records (AAAA records) and coordinates with NAT64 to translate and manage IP addresses for both IPv4 and IPv6 traffic.
- PROS
  - Allows for a complete migration to IPv6.
  - Supports a complete interaction with both IPv6 and IPv4 Internet content.
- CONS
  - Does not support IPv4 protocols that cannot interoperate in an NAT environment.
  - Difficult to scale and manage performance

These methods are not always independent and all inclusive. For example, if a CSP has a Quad Play offering (TV, Phone, Internet, and Wireless), DS-Lite may be a good solution for TV (Cable set top box) while still using an IPv6 Gateway, DNS64 and NAT64, and Dual Stack for other offering and systems. This architecture allows for a complete migration to an IPv6 offering while still supporting existing set top boxes at the customer locations.

The ultimate challenge is for CSP’s to migrate to IPv6 with as little impact to the subscriber experience. The method chosen by CSP’s needs to be able to migrate to IPv6 and still support current IPv4 content and applications, and this needs to be done seamlessly to the subscribers.

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