In what was hailed as a major accomplishment, CableLabs successfully completed a PacketCable 2.0 SIP call over IPv6 during a two-week IPv6 interoperability event last month.

With IPv4 blocks of addresses set to run out as early as next year, service providers have been working on their transitions to IPv6. While the migration to IPv6 has been in the works for years, the proliferation of IP devices on service providers' networks has caused a further drain on the remaining blocks of IPv4 addresses.

While IPv4 addresses are about to run out, IPv6 consists of 128 bits, compared with 32 bits in IPv4, resulting in approximately 340 undecillion IPv6 addresses versus the 4.2 billion available through IPv4.

"Suppliers have demonstrated significant progress in their support for IPv6. This is a very important technology for cable operators, and it is encouraging to see such a strong commitment from the industry's supply community," said Chris Donley, project director of network protocols at CableLabs.

Cox Communications and Comcast are both working on IPv6 trials in order to prepare for the transition.

The October interop was fourth in a series of semi-annual IPv6 events hosted by CableLabs in Broomfield, Colo.

"The recent CableLabs IPv6 interop proved extremely useful for Cox," said Jason Weil, principal architect for technology architecture at Cox Communications. "The CableLabs' team worked with Cox engineers to mimic our IPv6 dual-stack trial configuration, which included a DOCSIS 3.0 cable modem, stand-alone home gateway supporting DHCPv6 Prefix Delegation and Windows 7 client as part of the interop. We successfully tested IPv6 provisioning with multiple software vendors.

"The key to the interop success was having senior support engineers from all the participating suppliers onsite and working as a team through any issues in an expedited and efficient manner."

Representatives from 17 companies worked together to test IPv6 interoperability in a range of products including: DOCSIS 3.0 cable modems (CMs), DOCSIS 2.0 + IPv6 CMs, cable modem termination systems (CMTSs), PacketCable E-DVAs, set-top boxes, provisioning servers, home gateways, large-scale NAT servers and test tools.

Companies that participated in the interop included: A10, Arris, Broadcom, Cisco, Comcast, Cox, D-Link, Incognito, Motorola, SCTE, Shenick, Spirent, STMicroelectronics, Technicolor, Texas Instruments, Ubee and the University of New Hampshire Interop Lab.

Participants also tested DOCSIS IPv6 provisioning, Internet video streaming, and eRouter and standalone home router configuration, as well as interoperability with PCs running Windows XP, Windows 7, Mac OS X and Linux. In addition, CableLabs demonstrated NAT444 and Dual-Stack Lite, which it said were two important IPv4/IPv6 coexistence technologies.