What Enterprises Should Do About IPv6
Lalit S Chowdhary, Senior Vice President, System Engineering, Cisco India & SAARC
The Internet has been a rapidly growing communications medium for a few years now. With the rapid growth of the Internet over the last decade and more, the industry today is on the verge of running out of IPv4 addresses used to number devices on the Internet. The last block of IPv4 addresses to be given to an Internet service provider (ISP) is projected to happen in late 2012/2013. This means, the Internet will continue to function as it does today, but new public IPv4 addresses will be scarce, available only when they have been recovered from previous use.
IPv4 address exhaustion will have a major impact on the growth of the Internet, Internet service providers (ISP) and Internet presence (websites, e-commerce, email). Any ISP that wishes to continue to grow revenue by increasing its customer base will have to find a technique to add new Internet users. Transition to IPv6 seems to be a viable option.
While many enterprises have enough address space (public or private) to manage their intranet needs for the coming few years, the length of time needed to transition to IPv6 demands that administrators and managers consider the issue well in advance, because large enterprises may need to act sooner rather than later to ensure sufficient enterprise connectivity.
The transition to IPv6 helps businesses prevent increased cost, prevent disruption to website services in the long run and facilitates the growth of global business. By transitioning to IPv6, businesses can also avoid diminishing experience to their customers and have access to the supply chain. IPv6 is ready to deploy today and most organizations are undertaking the transition already.From IPv4 to IPv6
IPv4 and IPv6 are not compatible but they can use the same network simultaneously. Some options for integration and coexistence of IPv4/IPv6 include:
- Dual stack: All Internet users are given both a routable IPv4 and a routable IPv6 address (actually a network prefix). It is then up to the user’s computer to select which address to use. However this technique cannot be applied to all current and future Internet users because enough free IPv4 address blocks will not be available in future.
- Shared IPv4 address: The ISP shares a few globally routable IPv4 addresses among several customers. Each customer is assigned an IPv4 address used only within the ISP network. If a customer wants to access the Internet, then the customer packets will go through a Network Address Translation (NAT) device within the ISP network. The ISP can also provide IPv6 connectivity at the same time.
- IPv6-only: The ISP does not give any IPv4 Internet access to the customer. The customer will have access only to the IPv6 part of the Internet. Mobile operators in some countries intend to offer this connection on next-generation mobile handsets (Long Term Evolution [LTE]).
Service providers are likely to implement any of these three approaches over the short to medium term.What enterprises ask
For enterprises the IPv6 transition needs to be low-cost and low-risk, and needs to co-exist with existing IPv4 infrastructure. While in transition, businesses must still be able to access public IPv4 Internet, the integration should be seamless and must not impact existing services. IPv6 must be incrementally deployable and include the cost of adding new services. Most importantly it should not be easily apparent whether IPv4 or IPv6 is used.
While they transition from IPv4, enterprises have some questions on deploying IPv6. They include:
- Are there any regulations or incentives that require or encourage either the enterprise or its customer base to migrate to IPv6?
- Are there any customers or business partners who would not have access to IPv4 services?
- Are there any applications that would be severely affected if the Internet users are located behind a shared IPv4 address?
- Is there any performance or resiliency benefit either to adding IPv6 or to staying with IPv4?
- Is a unique identifier (like an IP address) important for the service?
- Are IPv4 address literals used by the service (e.g., http://192.0.2.1 in HTML pages)?
The answer to each of these questions is likely to be volatile and requires reconsideration from time to time. For instance, at this moment, there are likely few, if any, enterprises that are unable to get IPv4 addresses. Even if that changes, the vast majority of customers who cannot get unique IPv4 addresses will still have access to the IPv4 Internet through some form of NAT. This will be sufficient for simple web page access for some time to come. Direct IPv6 connectivity may be preferable for other more advanced services.
It is also entirely feasible to deploy IPv6 today and possibly see a drop in performance for dual-stack clients, depending on how clients order their connection attempts as well as the quality of the IPv6 network connection between the clients and the enterprise online services. As service and content Providers deploy IPv6, this problem is anticipated to dissipate.The transition
While ISPs are mainly concerned with IPv4 address exhaustion, enterprises should assess their exposure to IPv6. Enterprises must understand the impact of the 'new Internet' on their services, assess their own situations and requirements as early as possible; this includes network, security and business applications.
For a successful IPv6 adoption, businesses should start with a phased plan aligned with their business strategy and identify the highest priority IPv6-critical areas in the network. They should then perform IPv6 assessment on high priority areas to determine scope and develop a design that enables IPv6 without disrupting the IPv4 network. T hey must also test and implement in pilot mode, then extend over time into production.
It is quite possible that regulations and mandates will enforce the use of IPv6, but there are many other reasons for enterprises to move to IPv6: security, new application support, getting rid of NAT, easier network deployment, providing IPv6-only services to Internet newcomers, being ready for the future.
It is expected that for most enterprises adding IPv6 connectivity, Internet presence will be the highest priority because enterprises must offer services and content to their IPv6 customers over the Internet. This is also the easiest part. Providing IPv6 access to all internal users and applications is probably the next step especially if the enterprises move to the cloud computing paradigm or to web services. The last step will probably be adding IPv6 in the intranet and in the data center applications. This will take longer as there is a clear impact on the business applications.