As the transition from IP version 4 to version 6 looms on the horizon, there’s no
question that IPv4 has surpassed all other standards to date when it comes
to data transmission.
Are IPv6 and its predecessor enough to fuel the next surge in demand for
Internet services? Regardless of the revised protocols ability to expand
limited address space from a 32-bit standard to 128-bit address system,
other switching standards remain essential to deliver quality throughput of
broadband content.
Ross K. Ireland, SBC Communications’ (SBC)
senior vice president-network planning and engineering, cautions protocols like Asynchronous Transfer Mode won’t go away any time soon. But do
expect fiber to play a role as carriers look for ways to improve
application speeds.
“IP has clearly won at the edge of the network,” Ireland said. “For data
services, it’s the protocol of choice, and it’s already playing a huge role
in carrier networks.”
Ireland added that the challenge for carriers in the future would be
figuring out how to carry the data in the most efficient possible manner.
“Right now, the voice telephone network carries IP data if you dial into
your ISP. But that’s not the most efficient carriage because of the
relatively slow speeds,” Ireland said.
“IP doesn’t work very well in a voice environment where you have to deal
with circumstances like high-volume calling events like a toll-free number
for a ticket box office. So, there may not be one right answer, but many
alternatives based on optimizing customer applications,” Ireland added.
While the quality of data and voice transmission are the immediate industry
concerns, bandwidth-intensive applications like streaming audio and video
create even greater demands for carriers and ISPs alike.
Ireland said the bigger bandwidth demands require quality throughput.
“If you’re going to aggregate service like voice and video with data, the
reality is that IP may need help from layer 2 protocols, such as ATM, to
provide reliable, high quality service,” Ireland explained.
SBC is shooting for throughput rates of at least 1.5 megabits.
Ireland said it’s the sweet spot for video streaming and entertainment
video delivery.
“One-and-a-half megabits will support video streaming, and it is actually
quite good for entertainment video,” Ireland said. “We have set up our
Project Pronto to deliver 1.5 megabit throughput to over 80 percent of our
customer base.”
“Project Pronto” is SBC’s three-year $6 billion broadband initiative
launched late last year. The ambitious scheme is designed to deliver
broadband services to 80 percent of its customers over the next three
years. SBC is pushing fiber and Digital Subscriber Line equipment deeper
into its central offices to deploy advanced packet-switching technology.
Consequently, Ireland suggests that IP dominance lacks scalability, and
aggregate standards are required for quality data transport.
“IP is not a panacea,” Ireland said. Depending on the application, other
technologies will remain important.”
One of those technologies is asynchronous transfer mode, which SBC uses to
carry IP packets at high speeds. According to Ireland, unless engineers can
find a way for the IP protocol to take on some of the characteristics of
ATM, this protocol will continue to play an important role.
But Ireland contends that carriers and ISPs need to put first things, first.
“Carriers using IP for constant bit-rate services like video streaming have
a really difficult time guaranteeing quality of service,” Ireland said. “If
we can find an economic way to fix the QoS problem, then all we’ll be
scaling is application speed. And that’s okay, because we’re going to find
solutions on the speed side.”
