Ops Face the Era of Hybrid IPv4/IPv6 Networks

It is impossible to identify precisely what the next steps are for the industry on IPv6 deployment because, naturally, each operator is in a different stage of its evolution, each faces a different situation in its systems, and each has its own unique priorities and goals. There are, though, general comments that can be made on the decisions that operators will face as they come closer to implementing the new addressing scheme. The first step is to recognize that the highest level decision – the agreement that dual stack approaches in which IPv4 and IPv6 run in parallel – probably was the most important. What comes next is a set of more granular and, collectively, equally vital choices on how to actually deploy this necessary new technique. The first realization that operators must make is that though the new kid on the block is IPv6, the world of IPv4 will march on well into the future. Indeed, the true end of the older addressing scheme is not in sight. The decision in the short- and medium-term is not how IPv6 will replace IPv4. It is how the two will work together in a way that the newer technique gradually supersedes the older one. “A big thing to remember is that there are two pieces that get conflated at times …. One of them is IPv6 and the other is how to keep IPv4 alive until we don’t need it, which is a long way off,” said Chris Grundemann,CableLabs’ architect for IP networks. It may seem odd to be worrying about IPv4 just as IPv6′s profile on the landscape grows. But that is the case. Operators, insiders say, must take care in measuring the IPv4 addresses supply they have against the expected need. If they seem to be falling short, plans must be set for obtaining more, perhaps even on the open market. The survivalist tendencies of IPv4 lead to a couple of other decisions. Grundemann said operators need to think about how they are going to gradually shift device management functionality to IPv6. As the IPv4 pool of devices shrinks, he said, more and more of the vital oversight tasks can be assigned to the IPv6 management platform. This gradual transition frees IPv4 addresses that formerly were devoted to management tasks. Ironically, one of the techniques that service providers of all stripes use to stretch the IPv4 soup – network address translation (NAT) – still has a big role even after the rollout of IPv6, said John Brzozowski, the chief architect for IPv6 and distinguished engineer for Comcast (NASDAQ:CMCSA). NAT, he said, will remain a primary player in its role of using a single IPv4 address to link to the devices in the home that are not IPv6-capable. Another concern is that the availability of proper hardware and software once these decisions are made. Keven Adams, the director of CMTS product management for ARRIS (NASDAQ:ARRS), agreed that there are a great many architectural decisions to be made as the industry navigates the trip from IPv4 to a hybrid IPv6/v4 and, ultimately, a pure IPv6 network. He added that operators must make sure that their vendors offer products that support the path that they have chosen and that that support extends beyond betas into the actual available products. Mediating between IPv4 and IPv6 and managing the transition is not the only issue that cable operators need to think about. Nominum, a company that focuses on IP addressing mechanics such as domain name system (DNS) and dynamic host configuration protocol (DHCP), sees a challenge ahead for cable operators. In the IPv4 world, said Craig Sprosts, it is possible to amass information about every address the operator controls. This highly automated process can be used to create white lists and black lists and otherwise be used to manage how different end points are treated. For instance, a spammer could be identified by the IPv4 address. With IPv6, there are so many addresses that this approach simply won’t work, Sprosts said. New approaches – such as dynamic naming that Nominum offers – are necessary. The higher level point simply is that the number of IPv6 addresses is so much greater than IPv4 that fundamentally new approaches are necessary, at least in some cases. All of these issues must be worked through in a landscape in which the two other major stakeholders – content creators and consumer electronic equipment manufacturers – are outside the direct control of cable operators and are in various stages of readiness. That is a key issue, said Grundemann. “If I am an operator rolling out new services, I have to check if it is available in IPv6. If it is, I don’t have to turn up any IPv4 addresses.” The bottom line is that the industry has a gone a long way down the road toward IPv6 implementation. Clearly, however, there are significant twists and turns ahead. Carl Weinschenk is the Senior Editor of Broadband Technology Report. Reach him at carl@btreport.net. http://btreport.net/2013/04/ops-face-the-era-of-hybrid-ipv4ipv6-networks/

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