So you have decided that adding support for IPv6 is inevitable and you want to build a solid business case to justify...
a budget. Simple, right? Not exactly.
The scarcity of public IPv4 addresses is just not enough of a justification for most enterprises to take on the risk of a full scale IPv6 migration. Most have implemented network address translation (NAT), tunneling, or other transition techniques to limit the impact of the scarcity of addresses, and while it's true that most of your current infrastructure is IPv6 ready, turning up IPv6 also requires a bit more thought than simply re-configuring devices to talk IPv6 instead of IPv4. Unfortunately, there are also significant costs associated with switching to IPv6, so you'll need to build a business case. Let's make sure you've identified all of the potential IPv6 cost considerations and then weigh them against the benefits in part 2 of this article.
IPv6 cost considerations
First, you'll want to make sure you appoint a project manager that has experience with complex network implementations. Then make sure they consider the following IPv6 costs:
IPv6 address space best practices and training: You'll want to quickly secure a block of IPv6 address space for your enterprise. Given the larger number of host IP addresses available for IPv6, IP address space design best practices have shifted from preserving IP address spaces to optimizing IP address aggregation. IP aggregation is also known as supernetting, and is used as a means to optimize router performance. You will need to re-train your staff to understand how to aggregate your network and avoid common IPv6 security pitfalls.
Network hardware and software costs: Not all network equipment is IPv6 ready, and some routers that do support IPv6 do so using general purpose processors instead of dedicated hardware (like ASICs or network processors); this means that these routers process IPv6 packets with slower forwarding rates, resulting in reduced network performance.
Enterprise system management tools: Most organizations with large heterogeneous environments have a complex patchwork of both commercial off-the-shelf (COTS) and custom or homegrown network and system management tools. You'll need to inventory these tools, validate their IPv6 compliance and remediate or upgrade them.
SIP-based applications: Most applications don't care about the IP protocol of the underlying network. But some do, such as real-time services using the Session Initiation Protocol (SIP). SIP's creators made a crucial error by including IP address information within SIP message headers. Vendors and developers of SIP-based applications must reconfigure their apps to support IPv6 information in the SIP header. You'll need to make sure any of your SIP-based applications are ready for IPv6.
Provider services: Support for IPv6 is still not comprehensive, especially for services such as MPLS and residential Internet. Many residential routers don't yet include IPv6 support. Some top Internet service providers -- including Verizon, Comcast, NTT and Hurricane Electric -- are already well into their v6 deployments. Most carriers are adopting a dual-stack architecture; carrying both IPv4 and IPv6 while using "Carrier-Grade NAT" as a v4 to v6 gateway. But carrier grade NAT can introduce additional transit delay in the carrier's network. And many Internet architects worry that carrier grade NAT breaks the end-to-end Internet model; meaning that carriers can restrict unwanted services by not allowing them to transverse their NATs. Regardless, just make sure you know what each of your providers can support when it comes to IPv6.
Non-traditional IP devices: IP networks today consist of a lot more than routers, switches and PCs. Security and building management systems, sensors and M2M devices all will require that you analyze them for their ability to support IPv6. It's important that you plot either an upgrade or gateway strategy to ensure that legacy applications and devices can co-exist in a mixed IPv4/v6 network.
Now that we've considered where IPv6 costs can run, let's look at IPv6 benefits in part 2 to help you build an IPv6 business case.