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Power backup for VoIP spans Ethernet-with-UPS solution

Posted: 23 May 2005 ?? ?Print Version ?Bookmark and Share

Keywords:ups? ethernet? backup? voip? voice-over-ip?


Stressing that UPS backup will ultimately become mandatory for voice-over-IP (VoIP) applications, MGE touts its system as the first comprehensive solution for the secured PoE infrastructure-providing PoE midspan, UPS, and supervisory functions for Enterprise IT networks, which include VoIP. Anticipating similar integrations by its UPS competitors in the near future, MGE has designed its system to address reliability and plug-and-play issues with minimal fanfare while calling attention to the "true cost" issue as it applies to securing affordable system availability.

MGE comes into the midspan business citing customers' preference for these devices, versus PoE switch solutions, with the midspan viewed as part of the physical power infrastructure, i.e., a "DC PDU," working with the UPS. Their latest offering represents an extension of the one-stop shop concept. "You no longer have an AC outlet; power comes through the VoIP cabling," said Brad Amano, market segment manager, citing traditional wiring closet schemes that power Ethernet switches through the mains, but without any inherent power protection. "On the other hand, powering is much more critical through cable. Then again, the system designer doesn't have to worry about that, there's no need to bring in an electrician to do any wiring. We take care of that, all of it bundled in with the midspan (a "universal" PowerDSine product supporting both Cisco and non-Cisco devices) that slips between existing switches."

PoE can be installed in two ways; using a PoE midspan system; and using PoE Ethernet switches. In the former case, of greatest advantage in updating equipment at minimal cost (i.e., without adding new PoE switches), the midspan unit is installed between a standard Ethernet switch and the terminals without modifying the existing wiring. This solution, according to MGE, improves system availability even further when used with remote supervision of the midspan and the UPS. The PoE Ethernet switch solution, on the other hand, is best suited to installations starting from scratch. MGE has designed a system that, when backed by a UPS, is suited to either solution when it comes to providing the availability equivalent to traditional switched telephone networks, and the advantages of IP telephony.

MGE approaches the Enterprise IT issue as one that demands the same attention as the traditional telephone when it comes to system availability. As such, the company addresses the issue of reliability by employing its double-conversion UPSes to provide maximum protection for the networks. Adding the midspan without disturbing the existing wiring infrastructure simplifies the hook-up without the need to configure the system. As a result of these measures, the system minimizes overall overhead; the representative total cost of such a system, using the company's 3200 VA Pulsar RX RT interruptible power supply is $3,549-that is, $1,199 for the midspan, $1,950 for the UPS, and $400 for the Management-Pac 2, which includes the Enterprise Power Manager Software. Overall design issues and system costs would be unaffected by any future changes to the PoE standard calling for more power at each port.

To help with UPS considerations, the company anticipates providing the designer with website assistance on scaling their UPS needs to the requirements of the PoE system. The so-called "selector assistant" will be available on to help designers choose both the UPS and the appropriate complement of battery modules. As an example, a switch enclosure with 96 IP lines (24 ports, 4 switches) would require backup power in excess of 1200 watts (including allowance for expansion). For this example, a Pulsar EX RT 2200VA/1540W unit would be appropriate. Using a 3200VA/2080W unit with two of the company's EXB battery modules would provide a backup time of more than one hour.

- Vincent Biancomano


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