VoIP to lift $6-million Centrex weight off the city of broad shoulders, IT officials say.
The Chicago Public Schools, the nation’s third-largest school system, is starting a five-year VoIP rollout this month to improve communications among teachers and parents, while slashing millions of dollars in recurring telecom and maintenance expenses out of the school’s budget, city IT officials say.
The Chicago school system recently signed a $28 million deal with Mitel to install IP PBX hardware, voicemail and a mix of IP and digital telephone handsets across 700-plus schools and other facilities, with around 19,000 phones to be installed. The school system says it will save around $6 million per year, when the installation is complete, by eliminating its annual Centrex bills — which can run $20 to $25 per phone.
The current voice network a the Chicago Public Schools consists of disparate, standalone PBX phones systems from Avaya, and over 19,000 Centrex lines rented from AT&T on a monthly basis, according to Katie Zalewski, telecom director schools.
VoIP became a consideration as a replacement technology two years ago, when the school district upgraded its IP network equipment, installing Cisco switches and routers in the schools, and linking buildings with a mix of T-1 lines and Gigabit Ethernet fiber links.
“Our data network is very well established and very reliable,” Zalewski says. “Instead of reinventing the wheel, we decided to utilize that data net to pull voice traffic over it.”
Each site will get a Mitel IP Communications Platform (ICP) 3300 VoIP switch, capable of supporting up to several hundred phones per site. Two IP phones will be deployed in each principal’s office, with the rest of the phones being digital handsets.
“A lot of our schools are over 100 years old so we don’t have the [cabling] infrastructure at this point to go 100% IP,” Zalewski says. “It is very costly to upgrade an infrastructure for all IP handsets.”
All handsets installed in the school system’s administrative offices will be IP, totally around 3,000 sets in the department’s downtown Chicago offices. Between these offices and the schools, the IT department will manage around 5,000 IP phones total, Zalewski says
The 700 Mitel IPC 3300 phone switches deployed will share a common dial plan and directory, provided by a centralized Mitel Enterprise Manager server, which synchronizes data across the phone switches.
The Enterprise Manager will also allow the school’s IT staff to provide remote administration and support services to the schools, Zalewski says.
In the past, she says, “if anyone needed to move or reprogram a phone, or have a password change we had to send out a body.” Such IPC 3300 administrative and handset reprogramming tasks can be taken care of through the management software , Zalewski adds.
Key to the VoIP rollout is the recently-upgraded LAN and WAN infrastructure throughout the school district. Most middle and elementary schools in Chicago have a single Catalyst 6503 or 6606 switch chassis in the basement or communications closet. Instead of using separate routers and LAN switches in each school, all network gear is consolidated into a 6500 chassis for each site, which made for an easy deployment, and simplified management, says Steve Dorner, deputy CIO for the Chicago Public Schools, who oversaw the data upgrade.
The 6500s include LAN switching blades and a T-1 WAN interface card, making the chassis an all-in-one network box for each site. Blades with 10/100Mbps Ethernet ports connect computers, printers, a few IP phones, and the IPC 3300. A dual-T-1 WAN card connects the box back to one of seven Chicago high schools, which also serve as data network hubs, which fan out to the elementary/middle school “spokes” in the WAN.
QoS will be applied to VoIP traffic on both the LAN switches, and over the WAN links, using an eight-layer priority queuing system, Dorner says, with VoIP packets being tagged as the highest priority over other traffic to prevent interference with voice calls.
Catalyst 6509 switches in the high schools aggregate T-1 traffic from the branch schools. The high school-based Catalyst switches are set up in a mesh topology and connect via Gigabit Ethernet fiber links, provided by AT&T’s GigaMAN Ethernet service.
“Every network link has a redundant backup,” Dorner says. “If anything fails, there’s always an alternate path, so service is never lost.”
Dorner says there have been no configuration or interoperability problems to report among the Mitel VoIP gear and Cisco LAN/WAN equipment in field trials and lab tests. “Everything is [standards-based],” he says, such as the 802.3af power-over-Ethernet method used by Cisco switches to power Mitel phones, as well as 802.1p and DiffServ protocols used to prioritize Mitel VoIP packets on the Cisco infrastructure. “None of that has been an issue so far,” he says.
Calls made from phones in any of the satellite schools are sent over the IP network to one of the high school hubs, where calls are then connected to PSTN through ISDN PRI links, terminated by cards in the Catalyst 6509 switches. If for some reason a school is completely cut off from a hub site, local analog backup trunks allow the IPC 3300s to make outbound calls.
The school district is not deploying many advanced converged application features, but school employees are looking forward to one big upgrade they’ll use every day.
“Every employee — from teachers to the lunch ladies — will now have a voicemail box,” says Zalewski. She hopes that gone will be the days of pinning or stuffing notes for colleagues on bulletin boards or in mailboxes. Voicemail boxes will be hosted on a centralized Mitel NUPoint voicemail server in the school’s operations center. The voicemail system will give educators and parents a more direct way to communicate, she adds.
Much of the funding for the Chicago Public Schools VoIP project will be paid for through the U.S. Government’s E-Rate program, which provides network infrastructure funding for public schools and libraries, Zalewski says. In Chicago’s case, the city qualified for 86% of the project to be covered by E-Rate, covering IP PBX and network infrastructure costs. Phone handsets costs, not covered by E-Rate, will be picked up by the Chicago Public Schools central capital funding budget — a cost of around $8 million.
“In essence, a school itself does not have to pay a dime for this upgrade,” Zalewski adds.
