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Air-Blown Fiber Facts

The RCMP and Corrections Canada are both taking advantage of a novel installation process first developed by British Telecom a decade ago. Sumitomo Electric is leading the charge.


June 1, 2003  


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The Royal Canadian Mounted Police headquarters in Ottawa includes five buildings spread over a fairly large campus. That used to create a networking nightmare. It takes plenty of optical fiber to handle RCMP’s networking requirements.

“Every time we moved people we had to get another pair,” says Marty Gratton, manager of technical support at RCMP headquarters.

“It got to the point where they were running new conduits on a daily basis,” Gratton says. That meant opening trenches between the five buildings as well as disturbing people within the buildings as workers ran new fiber.

The trenches can stay filled in for a while now, though. The national police force has installed special conduit that allows new fiber to be blown in using compressed air or nitrogen without digging up the ground or cutting into walls.

A SIMPLE IDEA

The RCMP is one of a gradually growing number of organizations trying to cut down on the hassles of network moves, adds and changes by installing air-blown fiber, a technology that speeds up the addition of new fiber along existing routes.

The idea, developed at British Telecom more than a decade ago, is simple. Installers put in a special conduit divided into as many as 19 separate tubes. They can then add bundles of lightweight optical fiber by blowing them through the tubes from one end, without adding conduit.

The fiber bundles can be made up of two to 18 fibers. According to Sumitomo Electric Lightwave Corp. of Research Triangle Park, N.C., which manufactures the cabling used in the RCMP installation, two installers can blow the stuff in at speeds up to 150 feet per minute.

“It’s just a matter of blowing it through, terminating it, and we’re done,” says Kevin Black, project and account manager at Bell Canada, which handled the RCMP and other federal-government installations.

Relatively painless addition of new fiber means the RCMP can respond to new network needs faster, Gratton says. Instead of waiting until enough changes are needed to justify opening a trench, he can now order new fiber for one or two projects at a time. “Within a matter of maybe an hour they’re in and out and it’s ready to go.”

Black says blown-in fiber costs a little more for initial installation than conventional fiber, but the break-even point comes the first time a customer needs to add more capacity.

Sumitomo Electric claims air-blown fiber “compares favourably” with conventional fiber on initial installation costs, but saves about 97 per cent of the cost of future upgrades.

With conventional cabling, network managers face a choice. You can install just what you need now, and face the cost and disruption of installing more fiber in a few months. Or you can install enough dark fiber to meet anticipated needs for a few years, leaving it sitting idle until it’s needed.

Gratton says the RCMP decided air-blown fiber was a better choice than “spending a fortune now on stuff that’s just going to sit dormant.”

Black adds that installing dark fiber in anticipation of future needs is difficult because of the choices among various types of single-mode and multi-mode fiber. “Customers aren’t exactly sure what their applications are going to be five years down the road,” he says. Conduits for blown-in fiber can accommodate different types of fiber, so there’s no need for that guesswork now.

Ronald Gruia, enterprise communications program leader at research firm Frost & Sullivan Canada in Toronto, says saving money is one major argument for air-blown fiber. “In typical deployments you over-engineer because you want to have extra capacity built in,” says Gruia. Because air-blown fiber makes it easy to add capacity later, that over-engineering can be avoided. That means savings in cash flow.

According to Sumitomo Electric, old fiber can also easily be removed from the tubing and moved to another location, so it’s possible to replace lower-capacity fiber in one part of a network and then re-use the old fiber in another area where bandwidth requirements are lower.

The second argument for air-blown fiber is reliability, Gruia says. Because an air-blown installation involves fewer splices in the fiber, there are fewer likely points of failure.

Despite these points in its favour, Gruia says, air-blown fiber has not been widely used so far. It seems more popular in the public sector, he says.

The reasons for that are not clear, except that municipalities like it for metropolitan-area installations because it helps them avoid tearing up streets to add capacity later. Canada’s House of Commons and Health Canada have both installed air-blown fiber. In the U.S., it is used at the Pentagon, the National Institutes of Health and Las Vegas’ McCarran International Airport, among others.

The RCMP installation focuses on connections among the five buildings at headquarters, Gratton says — there is still some conventional fiber inside the buildings.

He says air-blown fiber has also improved security at RCMP headquarters. Tapping into fiber undetected requires connecting where there is a break in the fiber, such as at a patch panel. The blown-in fiber technology allows fiber to be blown through a closed conduit from point to point without breaks.

Previously fibers linking buildings at RCMP headquarters ran to patch panels in telecommunications rooms in each of the five buildings, with connections from there to computer rooms. Now the fibers run straight into the computer rooms, which are physically secured.

However, Gruia says security improvements are not a major argument for air-blown fiber in most cases – reliability is a more tangible benefit, he says.

Correctional Service Canada took advantage of an unusual opportunity to refit an Ottawa office building with air-blown fiber. Over several months the department’s eight-storey headquarters building at 340 Laurier Ave. West was gutted two floors at a time and its interior completely rebuilt from the insulation in. “There isn’t an inch of old cable left in our building,” says Hank Carr, chief of network facilities for Corrections. The new cabling uses air-blown fiber to connect the building’s telecommunications rooms.

Bell Canada and a subcontractor suggested the department look at air-blown fiber when the renovations began, Carr says, and “once we saw them actually install it, we were completely sold.”

The building has a relatively modest network, with just over 1,000 users.

“The way we’ve got our telecom rooms stacked, the distances are short,” Carr says. The initial installation consists of seven-tube conduit linking the telecom rooms, with 18 strands of multimode fiber running to each floor.

“Probably within the next year we’ll blow in more fiber,” Carr says. When that happens he expects to save plenty of time. “Instead of taking two days to run a fiber from the second floor to the seventh floor through all the riser closets, it takes two minutes,” Carr says. He adds that when the initial fiber went in, it took another two hours or so to fuse the 18 strands coming into the telecom room on each floor.

Correctional Service Canada is considering taking its use of air-blown fiber beyond 340 Laurier. The department occupies space in eight buildings in downtown Ottawa. One is at 360 Laurier W., where Corrections has one and a half floors for a training centre and “swing space” used to accommodate overflow from the building next door.

Right now, Carr says, adding network connections moving to 360 Laurier from 340 Laurier is “a major production.” Running air-blown fiber conduit through underground duct space leased from Bell Canada would make it much easier, Carr says, and avoid a lot of headaches should the department need to take over more space in 360 Laurier later.

Another of the Correctional Service’s Ottawa office locations is about two and a half blocks away from the Laurier Ave. offices, Carr says, and putting air-blown fiber through Bell Canada ducts to that building is also an interesting option. “To go that distance it would take 10 minutes to blow the fiber,” he notes.

Carr says the initial installation of air-blo
wn fiber at Corrections took about the same amount of time as installing conventional fiber. There are some particular tricks to working with the tubing because it is quite rigid, he says, but once installers get comfortable with it the installation goes smoothly.

The tubing also protects the fiber from physical damage, he says.

Carr says a representative from another federal department considering network upgrades contacted him recently to ask about his experience. “I said to him, you’d be (foolish) not to use air-blown fiber.”

Grant Buckler has written about information technology and telecommunications since 1980. He is now a freelance writer and editor living in Kingston, Ont. His e-mail address is gbuckler@cogeco.ca.