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Deploying IP telephony is hot issue

Mar 20, 20063 mins

PoE switches, servers heat up data centers.

While the IP telephony market heats up, thermometers are literally spiking in some wiring closets and computer rooms where VoIP and Power-over-Ethernet gear is being installed, users say.

Equipment density and overheating are constant issues for data-center managers. Beating the heat has become another concern for network and telecom staff deploying gear in wiring closets, as PoE and VoIP gear are set up in places that once just housed lower-power switches, cooler hubs and patch panel racks.

“Power in general has been our Achilles’ heel in our [IP telephony] deployment,” says John Haltom, network director at Erlanger Health Systems, a Southeast regional HMO based in Chattanooga, Tenn.

Achilles’ heel might overstate it, as Erlanger has deployed more than 1,500 IP phones in production, both wired and wireless, running on a Nortel Communication Server 1000 IP PBX. To support IP telephony, Haltom and his staff installed PoE switches in wiring closets to light up the phones and UPS equipment to allow switches to run during a power outage.

These redundancy and power requirements challenged the healthcare organization’s IT staff, which supports a 112-year-old hospital’s network and telecommunications systems.

“Trying to retrofit areas that are already cramped with larger PoE switches, larger UPSs” was the challenge, Haltom says. “By the way, all that gear generates more BTUs, so you have to upgrade the AC units in those closets.”

By most measures, wiring closets’ biggest heat boosters are PoE switches, which do double duty in transporting Ethernet traffic and acting as AC power supplies for IP phones and other PoE-capable gear plugged into the devices’ power ports. For example, Cisco’s non-PoE 24-port Cata­lyst 3750 LAN switch generates about 176 BTUs of heat per hour; add the PoE option, and the switch heats up to 534 BTUs. Add a standard UPS that dissipates 80 to 100 BTUs, and the heat output in one wiring closet more than triples to support IP telephony. Nortel’s 24-port Switch 420-T heats up to 220 BTU; its PoE-capable Switch 460-24T-PWR is more than double that.

Planning how this gear will be cooled and kept safe should not be an afterthought, experts say.

“All network devices should be placed in locations with . . . adequate heat dissipation, ventilation and air conditioning,” according to Salvatore Collora and Ed Leonhardt, two Cisco Certified Internet Experts, in Planning the Cisco Call­Man­ager Implementation, published in 2004 by Cisco Press. “Although it is surprising, some deployments actually store servers and switches in broom closets and under desks. Improper care of your equipment contributes to environmental and security hazards that can disable or degrade your voice deployment.”

This could especially be true in small businesses, where an older key telephone system is being replaced. These devices combined call processor, phone power supply and switching, and could be stored almost anywhere. However, companies should have a cool, dry place ready for newer IP PBX gear.

“In certain climates, you could have very high humidity, with the ambient temperature getting above [104 degrees],” says Patrick Ferriter, vice president of marketing for Zultys, a maker of IP PBXs that targets small offices as a key system replacement.

“There are places where it does get hot, and you’re going to have problems if you don’t have air conditioning.” How much cooling will depend on the IP PBX, he adds.

“If you have an IP PBX which has built-in gateways, and if you have a lot of analog connections — FXS boards that provide ring voltage — it could start to get even hotter,” Patrick says. “It’s going to be hotter than a traditional key system for sure.”