Internet Runs Out of Addresses2/07/2011 12:01 AM Eastern
It’s the end of the Internet as we’ve known
it — but cable feels fine.
All 4.3 billion of the unique addresses under the original Internet-
protocol addressing scheme, known as IPv4, have been
spoken for by the world’s regional registries. That means the
last IPv4 blocks will likely be allocated to service providers or
other networks before the end of 2011.
IP addresses function like traditional
postal addresses, providing
the critical routing information that
lets Internet users send and receive
The exhaustion of the IPv4 address
supply has been anticipated
for two decades, and the cable industry
and other network providers
claim they’re well-equipped to
start bringing up IPv6, the nextgeneration
Internet protocol that
provides a cosmically enormous number of unique addresses.
MSOs have a number of strategies for coping with
the coexistence of IPv4 and v6 — which are fundamentally
incompatible — for years to come.
“This is an inflection point in the evolution of the Internet,”
Juniper Networks director of software engineering
Alain Durand said.
The event marking that milestone happened last week,
when the Internet Assigned Numbers Authority, which is
responsible for managing IP address and domain-name
allocations, distributed two IPv4 address blocks to the
Asian-Pacific Network Information Centre (APNIC). Th at
triggered a provision in IANA’s rules to release the last five
IPv4 address groups, each with about 16.7 million addresses,
to the regional Internet registries.
But in the immortal words of sci-fi author and humorist
Douglas Adams: Don’t panic.
The IPv4-based Internet isn’t going away. Indeed, network
providers have several tools they’ll use to gradually introduce
IPv6 while maintaining IPv4 addresses more efficiently. Th ese include large-scale, carrier-grade network address
translation systems from Cisco Systems, Juniper and
others to let IPv6 client devices access IPv4 resources.
As Durand put it: “I think my grandchildren will still see
some IPv4 devices in use.”
The goal is for residential and business customers to
never even know which protocol their computers or home
networks are using. “A subscriber should never have to
type an IPv6 address into their browser,” Cox Communications
senior director of architecture
Jeff Finkelstein said.
The cable industry earnestly began
getting ready for IPv6 in 2004.
CableLabs designed the DOCSIS 3.0
specification to support IPv6 from
the outset, while the older DOCSIS
2.0 accommodates IPv6 through
upgraded DOCSIS 3.0-compliant
cable-modem termination systems.
Likewise, PacketCable 2.0 includes
support for IPv6.
Now the technology is getting tested in the field.
Comcast this month initiated the first North American
test of IPv6 running natively in a DOCSIS environment,
with a group of cable-modem users in Colorado, and plans
to widen it to other areas of the country. Th e MSO implemented
a “dual stack” configuration, in which cable modems
are able to natively access both IPv4 and IPv6 content
and services without any translation.
“This is a tremendous milestone for Comcast, cable operators,
DOCSIS technology and the Internet community
at large,” Comcast distinguished engineer and chief architect
for IPv6 John Brzozowski wrote in a Jan. 31 blog post.
Cox is assessing the full scope of the deployment issues
involved with IPv6, which is a much more complex protocol
than its predecessor, Finkelstein said.
“There’s much more to IPv6 than just the large address
space,” he said. “We can’t wait until the last minute to train
The majority of Cox’s data network is running DOCSIS
3.0, but even after it is 100% upgraded, “there is a small percentage
of devices that are just not going to be upgradable
to IPv6 and we have to be aware of that,” Finkelstein said.
Time Warner Cable, for its part, plans to begin residential
IPv6 trials this spring and expects to adopt a dual-stack
approach. The MSO signed up its first commercial customer
using native IPv6 over its fiber-access product last year.
And CableLabs and various operators plan to participate
in World IPv6 Day on June 8, 2011, an event sponsored by
the Internet Society to let websites “test drive” IPv6 for a
However, many Internet-service providers still are not
prepared for the advent of IPv6 — and will find themselves
unable to grow their businesses if they don’t get on the ball,
according to John Curran, president and CEO of the American
Registry for Internet Numbers.
“For some reason, despite 20 years of planning, a lot
of organizations don’t seem to know this is happening,”
he said. “Some network operators looked at IPv6 as a science
project. … Hopefully, this little wakeup call will get