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Current Issue: April - May 2008
Migration paths to NGN | Last-mile networks
Broadband penetrates the badlands
SRT sets future fiber and IP path
by Sean Buckley
If there is one word to describe Minot, N.D.-based SRT Telecom, it is "diverse."
For one thing, SRT is a jack-of-all-trades carrier offering everything from basic POTS to residential DSL broadband, business services, wireless, and, finally, a traditional cable TV network.
At the same time, SRT’s geographic service area encompasses two ends of the spectrum: both metro and remote rural customers.
To set a path for new packet- and fiber-based services, while maintaining its current customer base, SRT decided to deploy Zhone’s Multi Access Line Concentrator (MALC) and zNID outdoor gateway to extend Active Ethernet-based FTTH to its rural customers.
With all those network elements to manage, the main issue SRT faces is allocating the right funds to support its diverse products.
"We’re running a voice, video and data, and a wireless network," says Shawn Grosz, SRT’s director of network technology. "Every year, we start our budget process around July [and] finish up in September. Everyone is juggling for dollars each year when you have to keep projects going, expansion, upgrades and maintenance costs."
A targeted fiber approach
SRT’s diverse geography and service set lends itself to some unique challenges and prospects. When it comes to rolling out fiber to the home (FTTH), SRT takes an opportunistic approach.
In its existing larger communities where it has an abundance of copper plant, SRT’s near-term strategy has been to build 6,000-foot customer serving areas with a focus on stretching the existing copper via ADSL2+, copper pair bonding and VDSL.
While not ruling out bringing fiber to its existing brownfield areas, at this point SRT is focusing its fiber build on remote rural areas and greenfield applications over the same MALC platform it’s using to deliver DSL (see Figure 1. Active Ethernet network, right).
Taking its name from the Souris River—a river that runs through its metro territory and stretches into the rural Drift Plains—SRT’s main challenge was its ability to expand broadband access to its rural customer base. In its rural areas, the distance between the homes and the CO made extending DSL service nearly impossible.
Grosz emphasizes that the only connection these remote areas have to their network is lifeline voice and maybe some dial-up capabilities. What’s more, in many of these rural areas the copper has become so degraded even traditional voice is becoming problematic.
"We have targeted our rural areas with FTTH," Grosz says. "I am not talking rural towns, but the very rural farmsteads where in some cases we have loops of 20 miles where broadband services are very difficult to reach. We have taken the approach of serving those customers who can’t be served with fiber."
Future-proof mentality
Despite the initial upfront expense, SRT has future proofed its network by installing fiber at each rural subscriber location.
SRT runs four fibers at each customer site. A single fiber goes to the customer’s house and is then home run back to the CO. By using small form, pluggable-based optics, each customer gets its own fiber run.
"We kind of future proof ourselves to offer 100Mbps services to each subscriber…some of which are 20 miles out," Grosz said.
After installing 25 MALC units with the new Active Ethernet and the zNID gateway in December, SRT began a pilot rollout of its Active Ethernet fiber service initially to five customer sites.
SRT is now in the midst of Phase I of its upgrade project where it will extend voice and high-speed data over fiber to 129 subscribers. In July, SRT will begin Phase II of its Active Ethernet deployment.
Of course, during the initial deployments it had to deal with gaining necessary rights of way, not to mention the cold weather. Prior to pulling the trigger with its Active Ethernet deployment, SRT asked Zhone to make some minor adjustments to the outside zNID ONU platform to accommodate the environment in which it operates (see Figure 2. Outdoor gateway, right).
"We have an environment where in January the temperature was actually minus 40 degrees, and the wind chill dropped that to 65 to 70 below," Grosz says. "We have some unique environmental challenges."
Packet preparation
SRT’s future-proof strategy with fiber lends itself nicely to supporting its future VoIP and IPTV service rollouts. Leveraging Zhone for these upgrades, especially voice, made sense since the MALC has a GR.303 interface to work with its existing Nortel DMS 500 Class 5 switch.
Interestingly enough, SRT’s relationship with Zhone actually has a Nortel connection. Zhone acquired Nortel’s Access Node product line, which SRT is fazing out of its network, in the late 1990s.
SRT is using the same platform initially designed to support its ADSL service base, which ultimately grew to 12,000 subscribers to support TDM-based voice.
At the customer premises, Zhone’s zNID outside gateway can not only provide higher speed data, but also VoIP and video when ready.
Ultimately, SRT wants to transition to VoIP on its Nortel CS-2000 softswitch in 2009.
"By taking some steps at a time, it has allowed us to do an easier migration with a traditional TDM switch in the host office, but we have a future plan to move that to our softswitch probably in 2009," Grosz says. "That’s not really related to Zhone, it’s more related to the fact that we need to put SIP in our Nortel softswitch, which is today MGCP-based."
And while Grosz recognizes that traditional voice pays the bills, he’s keen on offering enhanced interactive voice services not possible with a traditional TDM network. The ongoing migration to SIP could lend itself to new IPTV services such as on-screen TV calling or screen pops of sports scores.
"There’s a tremendous amount of opportunity once we move to some SIP services in the future," he says.
At this point, SRT has no immediate IPTV plans. It is installing a new cable headend from Motorola to a digital RF cable plant to support 200 channels where it has cable TV franchises.
SRT expects to take the rest of 2008 to finish the RF video upgrade to the communities where it offers traditional HFC-based video. That’s not to say SRT is not thinking about IPTV.
"In the future, we plan to packetize that [cable TV] network in other areas, but we have not made a determination when that’s going to happen," Grosz says. "We have not determined when we’re going to do IPTV; we’re just positioning our network."
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