Why the Transition to IPv6 Is So Tricky
by Leslie Ellis // November 09 2009
For such a nerdy, network-y name, IPv6 rides with some pretty colorful language. Without it, for instance, the global Internet faces “IP address exhaustion.” With it, we could theoretically affix an IP address to “every atom on the surface of Earth.”
But getting to IPv6 (from IPv4) won’t be trivial, engineers said over and over during the recent SCTE Cable Tec Expo. (And in engineer-speak, “non-trivial” is several shades darker than “really challenging.”)
Here’s the situation: We’re running out of IP addresses, and pretty much everything needs one. Bad news for any TV, PC or handheld screen craving an Internet connection.
Two entities are the keepers of Internet Protocol addresses: IANA, the Internet Assigned Numbers Authority, and ARIN, the American Registry for Internet Numbers. IANA runs dry by the end of next year; ARIN in 2012.
That’s why it’s good that so many IPv6 addresses are on deck – except for the largess of getting backbone, access and in-home networks ready for them. Turns out that the coexistence of IPv4 and IPv6 addresses is … well … non-trivial.
From a consumer perspective, if the bits moving to or from a screen affixed to an IPv6 addresses smack into any gear the route that only knows IPv4, whatever that consumer was looking at won’t load right, at least the first time. It’ll seem like a slowdown, or a glitch, and it will happen on the day you hit every red light on the way to work, while feeling like you’re getting a cold.
For the caretakers of broadband, going to IPv6 requires careful planning and phasing. (This particular point is consistently bracketed in “I can’t emphasize this enough” admonitions from the engineers working on it.)
The transition itself can go down in at least three ways. Safest, from a consumer perspective, is “dual stacking,” which means gear that speaks both v4 and v6.
Or, there’s tunneling, also known as encapsulation, which sidelines into terminology like “6to4,” “ISATAP,” and “Teredo.” All describe different was of making the new stuff look and act like the old stuff.
Also an option: Network address translation, or NAT, which does the opposite – it translates v4 addresses into v6 addresses.
Other, more tactical considerations: Getting the actual IPv6 address allocations; deciding where to start transitioning – core, or edge; picking routing protocols; prepping all back-office functions; and making sure all bases are covered — so that the new, v6 stuff doesn’t put the existing, v4 stuff at risk.
Bottom line, and to quote Comcast’s John Brzozowski, chief IPv6 architect and principle engineer: “This is no one-man show. Everyone in your company has something to do with the success of your v6 program.”
Best get on it.
This column originally appeared in the Platforms section of Multichannel News.
Update: Today (11/10/09) I heard from Marissa, on behalf of ARIN. She asks to clarify two points:
“In actuality, the IANA, operated by ICANN and is the central global entity that oversees global IP address allocation. ARIN is one of 5 Regional Internet Registries (RIRs) which receives IP addresses from the IANA. IANA delegates the allocation of IP addresses to RIRs in large blocks. The RIRs sub-allocate smaller blocks directly to Internet ISPs and network operators within their respective regions – ARIN’s region is the United States, Canada and many Caribbean and North Atlantic islands.
She also points out that IANA and ARIN “could” run dry in the timeframes suggested within the column. The “could” indicates that the RIRs “are not sure of an exact date, or even year.”
Thanks for the update, Marissa.