IPv6 Migration Strategy

IPv6 is here and its no more an option.

IPv6 is enabling the new Internet, creating new opportunities for business growth. Organizations need to enable IPv6 on their networks to maintain critical connectivity with partners, customers, and employees. You can accomplish this using a phased approach that reduces disruption to your business and incorporates industry best practices and knowledge gained from successful customer deployments.

Lets have a look at the strategy which should be followed while migrating to IPv6. I found a strategy diagram on Cisco.com, to which at least I am agreeing –

Now, Lets have a look at the strategy in brief –

Business and Network Discovery

The first step toward deployment is business and network discovery, where an organization identifies high-level business requirements for the migration, including timing, as well as external considerations such as regional address availability and government compliance. These requirements and considerations align to assets within the enterprise that must IPv6 enabled such as the corporate WAN, the security infrastructure, network services, and critical applications.

Deployment Assessment

In the assessment phase, an organization lays out its technical requirements and determines how to best deploy the technology with goals of minimizing disruption, facilitating troubleshooting, and containing implementation costs. As part of the assessment, various deployment options, such as dual-stack or hybrid models, are jointly discussed, along with desktop and data center support. The result is a high-level implementation plan that covers all IT assets.

Planning and Design

The design phase is where the proverbial rubber hits the road. Because you cannot map a route without knowing the destination, you should decide on the deployment model before beginning any design. There are three deployment models to consider.

Dual-Stack Model

In the dual-stack model, desktops, the campus, hosts within the data center, and any connectivity to the outside world are both IPv4 and IPv6 enabled in most cases. This model works quite well if some parts of the enterprise are IPv6 only, because they will have access to all resources. Where a user is capable of only IPv4, the IPv6 infrastructure will be invisible. The dual-stack model also facilitates longer term IPv4 phase-out by providing for incremental IPv6 deployment. Planning includes migration of routers and switches to IPv6-capable Software releases and in some cases IPv6-capable hardware. The same applies for servers and applications within the data center, as well as any virtualization infrastructure.

Hybrid Model

Where all network assets cannot be IPv6 enabled, the hybrid model may be more appropriate. In this model, access to IPv6 resources from an IPv6 desktop relies on tunnels across an IPv4 campus or enterprise backbone (either private or provider based). This model supports options where either the access and distribution switches or the core is not yet IPv6 enabled.

Service Block Model

A third model, the service block model, facilitates quick support of IPv6 where the campus network is not yet IPv6 enabled. It is an interim solution that can facilitate migration to the dual-stack model and, like the hybrid model, also takes advantage of tunneling. In most cases, given increasing desktop support for IPv6, best practices call for the dual-stack model across the entire network infrastructure: WAN, campus, data center.

Developing a Detailed Design

The detailed design includes the IPv6 addressing plan; physical connectivity considerations, including WAN links and wireless LANs; creating and managing VLANs and their associated protocols; and the routing infrastructure to include provider connectivity, high availability, multicast (if required), quality of service, manageability, scalability, and performance.


Security is a crucial consideration in IPv6 migration. IPv6 is not an update of IPv4 but an entirely new suite of protocols, raising new security challenges. Because of these unknown risks, organizations should adequately resource for such areas as firewall and intrusion prevention device readiness and IT expertise to properly identify and remedy threats. They should verify the readiness of third-party security suppliers (such as virus signature authorities), recognize complexities and tradeoffs in the various address assignment methods, and ensure the quality of OS and application implementations. Sure, IPv6 offers the promise of end-to-end encryption, but the initial homework must be done. IPv6 implementation will result in a transition period that offers organizations the time they need to learn and develop security best practices.


With the growing emphasis on virtualization and the mobile enterprise, which are often interrelated, IPv6 support is critical but is also an area where organizations have less expertise. You should work closely with your data center virtualization provider to understand the potential effects of IPv6 migration on remote access to corporate assets using smartphones or tablets.


The final stage of the planning process is to develop a plan for implementation and testing. Given proper planning, the actual IPv6 implementation should be the low-risk part of the process. You initially deploy IPv6 within the lab or on a limited pilot network, covering the complete set of network devices, applications, and desktops targeted as the initial candidates for integration in the planning process. The test should exercise each element of the design and, if the deployment spans geographies, validate the design for each geography.

The pilot is an opportunity to solicit user feedback and eliminate problems that will likely be discovered as part of the larger deployment. It is critical to keep affected users informed of the deployment and to establish an effective feedback process.
Extending the pilot to a regional or line-of-business deployment is the next step.


Once you have deployed IPv6, your work has just begun. The adoption process is a closed loop that offers opportunities for continual feedback and optimization. Your vendor should work closely with you to analyze operational metrics, any unexpected behavior, and, most importantly, the user experience. You will end up with a list of improvements that add additional capabilities and business value.

The challenges are not insurmountable. It is critical to adhere to best practices, while working with a trusted vendor throughout the process. The vendor you select should have the experience to help you develop in-house expertise, apply best practices to avoid common pitfalls, and provide support as you begin the deployment process. Assess the success of your deployment by how well IPv6 integrates within your network and preserves existing investments, and how the smooth and incremental transition through IPv4 and IPv6 interoperability ultimately sets the stage for a more productive and global enterprise. But what exactly does this mean, and just how do you begin the process?

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