Internet2 IPv6 Panel recap

6 minute read

A few notes from last month’s IPv6 deployment panel at the Fall Internet2 Member Meeting in Philadelphia, which I moderated (October 2nd 2012). Watch the entire video of the session (1 hour 15 minutes) for full details.

I opened the session with a brief review of World IPv6 Launch and some its measurement data, and a mention of other IPv6 deployment measurement projects, including the NIST survey of universities.

ARIN - Mark Kosters, CTO

Mark began his presentation by talking about the current state of IPv4 address depletion. ARIN has 2.87 /8 equivalent address blocks left (note: it’s down to 2.79 as of Nov 18th). RIPE and APNIC are almost out, below the one /8 threshold at which a real address rationing stage has already begun - they will give out a maximum of only /20 or /22 sized blocks regardless of how much IPv4 address space you really need. With current projections, ARIN is scheduled to exhaust in August 2013, but events could dramatically change the timeline. For example there are some ISPs in the ARIN region that could easily qualify for /9 allocations. ARIN is in phase 2 of a 4-phase runout plan - details can be seen at Today, 58% of ARIN’s membership has only IPv4 address space, 6% has only IPv6, and 36% have both IPv4 and IPv6 space. Legacy address blocks (ie. allocated to organizations prior to ARIN’s existence - this is quite common in the US higher ed community) comprise 45% of the ARIN address space.

The second part of Mark’s talk was about IPv6 deployment activites at ARIN itself. He went through a short history of their IPv6 implementation, which dates back to 2003, at which time they had a somewhat creaky, segregated (ie. non dualstack) implementation. By 2008 they migrated to a robust dualstack implementation. All ARIN services today are native, dualstack. Meeting networks are a bit more challenging, where they often have to rely on tunnels (due to hotel carrier limitations).

Comcast - John Brzozowski, Chief IPv6 Architect

Comcast now has IPv6 enabled on 50% of their broadband network footprint. However only 2.5% of the customer base is currently dualstack - of these dualstack users about 65% are using a computer directly connected to the cable modem, and 35% have an IPv6 enabled home router to which devices are attached. Comcast expects this ratio will eventually flip over to 80/20 in favor of home routers as it is in IPv4. To date, their focus has been on residential broadband, but they have pilots for business and commercial service. The Comcast metro ethernet service is IPv6 ready and they’d love to have more customers using it. In terms of traffic, Comcast has seen a 375% increase in IPv6 compared to World IPv6 day (June, 2011), with the majority of the increase occurring between January and June 2012, in the run up to World IPv6 Launch. The majority of the traffic is composed of services like Youtube and Netflix. The 2012 Olympics (streamed by Comcast/NBC in the US) had a noticeable impact - about 6% of this traffic to Comcast customers used IPv6. Comcast continues to work on content and services. Xfinity and are IPv6 enabled and they use Akamai as a content delivery network.

They’ve put in place an extensive measurement and metrics platform to proactively detect any adverse affects on customer experience and take action if needed. Comcast sees advantages to IPv6 beyond the usual address space depletion concerns. An example cited was the fact that once they’ve allocated an IPv6 subnet, they don’t have to be concerned about resizing it again, in marked contrast to their IPv4 deployment - this adds up over time to a significant operational benefit.

Marist College - Eric Kenny

Marist College is located in upstate network with 5,500 students on a 180-acre campus with 50 buildings. They started IPv6 deployment in 2010, and by June 2012 the wired network was mostly done. They plan to deploy IPv6 to the wireless network in the winter of 2012. One big item for them was getting provider independent address space from ARIN (mostly internal process issues). They started with a provider allocated block from NySERNET, but eventually got a /48 from ARIN, and are now wondering if they should have applied for a larger block. They also have a native IPv6 BGP peering with their commercial ISP, Lightower, which was described as an interesting experience, since they were their first IPv6 customer. They use stateless address autoconfiguration, and most devices on their network support IPv6. They haven’t yet made much progress with IPv6 enabled network services, apart from DNS. At the current time about 4% of the traffic crossing their border is IPv6 - they expect this number to go up considerably after wireless deployment. One of their biggest concerns has been address tracking and accountability. They’ve developed their own application to track IPv6 address and MAC address associations.

Louisiana State University - Allie Hopkins

Allie focussed more on the application and process side of things. As part of their rollout process, LSU has had a great dialog with the user community, with extensive outreach and communications via message boards and e-mail lists, and close contact with application developers and deployers. And despite a set of issues (described later), they rate their deployment a success and as can be seen from World IPv6 Launch measurements, they generate a substantial amount of traffic. One of the issues they’ve had is with their DNS based network registration system which was incapable of working properly with IPv6 enabled hosts. Another issue they encountered was connectivity issues between tagged and untagged VLANs on interfaces, due to the Cisco routers using the same IPv6 link local addresses on them - this was fixed by manually configuring unique addresses on the VLAN interfaces. They’ve also had ongoing issues with being put on Google’s AAAA blacklist. They are aware that they have some pockets of poor IPv6 connectivity within their campus network, but so far they’ve gotten no help from Google about measurement data that could help them more easily track down these cases.

I was scheduled to do a short presentation about IPv6 at Penn, but I decided to skip it (I’ll post the slides later) in the interests of providing more time for audience discussion and questions.

Q&A Portion

Richard Machida (U of Alaska) asked if anyone was looking into deploying IPv6-only networks for any purpose. I answered that we’ve deployed them only in the lab for testing purposes (longer term, we would investigate whether it’s possible to run specific applications that may not need IPv4, like VoIP on them). John says Comcast has no IPv6-only networks, but they do have plenty of IPv6-only devices that sit on dual-stack networks.

There was a question about more details of LSU’s network registration system (from what I gathered it’s a Netreg or Netreg like system), and whether 802.1x based network access control would be a solution (802.1x authentication happens at the link layer and is IP protocol independent). It probably would, but LSU was not quite prepared to deploy it yet.

There was discussion about what folks were doing about measuring IPv4 vs IPv6 traffic. Comcast went into some more detail about their work. I showed some data from Penn, where over the summer we were approaching 11% inbound and 4% outbound traffic composed of IPv6. We’ve since dropped down substantially, because we had to take IPv6 off the wireless network (I’m planning to write another blog article detailing why, but the quick summary is that deploying v6 broke IP address mobility, and we’re working with our wireless equipment vendor on some possible solutions).

Dan Magorian (Johns Hopkins) asked what cable modem data specifications support IPv6 and what is the state of IPv6 support in the currently deployed field. John’s answer is that DOCSIS 3, the current spec supports it pretty completely, almost all current equipment implements it, but there are ways to support IPv6 on older specs too.

Addendum: John B was one of the recipients of the Internet Society’s Itojun Service Award recently, and presented at IETF’85, for his “for his tireless efforts in providing IPv6 connectivity to cable broadband users across North America and evangelizing the importance of IPv6 deployment globally”. Congratulations John!

Shumon Huque