Thursday, 25 March 2010

As much as one percent of the Internet is now using IPv6

This week, the IETF is holding its 77th meeting in Anaheim, California. Last year around this time, the IETF met in San Francisco, and the Internet Society took advantage of this large gathering of Internet engineers to promote IPv6 and tell us that that it's high time to trade in the dusty 1980s Internet Protocol for the shiny 1995 version. Tuesday, the news was that people are actually starting to heed the advice.

Geoff Huston of APNIC, the registry that gives out IP addresses in the Asia-Pacific region, looked at various numbers that could tell us how much traction IPv6 is gaining. One metric that's easy to observe is the global routing table. After all, if you want people to reach your IP addresses, you'll have to tell them what those addresses are so packets can be routed in the right direction. This is done with the BGP routing protocol.

Currently, there are more than 322,500 IPv4 address ranges announced in BGP, and 2,770 IPv6 address ranges. However, because of the need to conserve IPv4 addresses, ISPs get small IPv4 blocks and frequently have to come back for more. Meanwhile, they can get a single, huge IPv6 block all at once, making this an apples-to-oranges comparison.

The number of BGP-capable networks that are sending out an IPv6 announcement is a more useful measure, and this totals 34,214 for IPv4 and 2,090 for IPv6. So 6.1 percent of all networks have IPv6 enabled in their routers. This metric is expected to reach 80 percent by 2017 if current trends continue.

Transit networks—ISPs that in turn have ISPs or other BGP-capable networks as their customers—have relatively high IPv6 deployment: 22 percent.

Huston also looked at the ratio between the number of distinct IPv4 and IPv6 addresses seen by the Web servers of APNIC and its European counterpart RIPE. This ratio is now slightly over one percent. Caveats apply, however. Multiple IPv4 users may share an address through Network Address Translation while a single IPv6 user may be using different addresses over time due to address privacy mechanisms. Also, the Regional Internet Registries aren't exactly mainstream Web destinations; their visitors are very likely more IPv6-capable than average.

Comcast's Jason Livingood had some information to share about the IPv6 trial the cable giant recently initiated. More than 5,400 people volunteered, with some even changing ISPs to be able to do so. Comcast already has a number of systems running native IPv6: the backbone network, peering points (where traffic is exchanged with other ISPs and content networks), "converged regional area networks (CRANs)," DNS servers (authoritative and resolvers), DHCP servers, and the provisioning system. Next are the Cable Modem Termination Systems (CMTSs), CPEs (Customer Premise Equipment), and home gateways.

Comcast has its own IPv6 monitor, which shows that IPv6 reachability for the top 1 million websites is only about a sixth of a percent. Another IPv6 deployment monitor shows 2.4 percent of the Alexa Worldwide Top 500 Web Sites have IPv6 addresses in the DNS, and several country top 500 lists have percentages ranging from 0.8 (US and UK) to 2 (China).

Yet another metric is provided by the Amsterdam Internet Exchange. Its IPv6 traffic has been hovering around the 0.2 percent mark for the past year. This is traffic exchanged by some 200 large and small ISPs and content networks present in Amsterdam, reaching almost a terabit at peak times, with about 1.5 gigabits of IPv6 traffic. Actually, 0.2 percent is higher than expected: if one percent of all users have IPv6, and one percent of all servers have IPv6, that would make one percent of one percent of all traffic IPv6 traffic.

Some of this maddening inconsistency can be blamed on Google, which has two IPv6-capable destinations in the Web top 10: google.com itself and youtube.com, which gained IPv6 recently. However, most people with IPv6 connectivity will reach these over IPv4, because Google only discloses its IPv6 addresses to DNS servers that have been accepted into the Google over IPv6 program. Jason Livingood explains that Comcast saw a large spike in IPv6-reachable Web destinations "due partly to content owners adding Comcast DNS servers to their authoritative server whitelist."

Don't forget: we've used 3,026 million IPv4 addresses and have just 680 million to go, with 203 million used up in 2009. Time is running out.