While support is improving for Enhanced 911 emergency services on corporate VoIP systems, IT professionals and analysts say the technology is not yet standardized across platforms and can be tricky to use in mixed-vendor environments.E911 is the FCC's advanced version of the well-known 911 emergency-calling system that provides additional location data to emergency responders, such as street address and floor inside a building. Carriers have a deadline to implement all phases of e911, which includes extended data from wired phones, and the location (within 1,000 feet) for cell phone users. The FCC's deadline for implementing this system is October 2005.Residential VoIP service provider Vonage last year made 911 tracking possible for its customers through a partnership with a 911 telecom services firm. For a company, one of the so-called "blessings of VoIP" turns out to be a curse in terms of e911.IP phones can be moved easily throughout a company, allowing for quick and easy moves and changes. However, this mobility also can make physical tracking of the phones difficult. Then there's the issue of remote workers using VoIP to access a remote PBX.The nightmare scenario in an enterprise VoIP network might look like this: An ambulance shows up at a corporate office, but the 911 dialer actually is working from home with a IP softphone linked to the office by a VoIP VPN link. This example is extreme, but there are real issues with just getting location information for VoIP users inside a company facility.Companies with VoIP networks that lack appropriate e911 support could face legal issues from employees if a call made from an IP phone during an emergency is mishandled for technical reasons, according to Mark Lies, a senior member of Seyfarth Shaw, a Chicago law firm specializing in labor issues.Financial risk"If enterprise phone systems aren't configured to provide authorities with the exact location of an emergency caller, they could be subjecting their owners to undue financial risk," Lies says.Methods vary widely among vendors on how to deliver e911 information to approximately 2,000 911 call centers in the U.S., known as public safety answering points (PSAP).E911 support exists in Cisco's CallManager IP PBX software, where a phone's locations can be entered into a database manually. The Emergency Responder product is an add-on to its CallManager IP PBX software, which lets the locations of Cisco IP phones be tracked in a database that is updated automatically when phones are moved. This data is then uploaded to a local PSAP database. However, the physical tracing of phone locations relies on Cisco Discovery Protocol, a device-to-device communications technology Cisco Catalyst switches and phones support.For tracking IP phone locations, 3Com promotes its Network Jack 200 (NJ200) - a small four-port switch installed in cubicles as a wall jack replacement. With network mapping tools, 3Com IP phones can be traced to the NJ200 outlets they are plugged into, giving emergency responders the location of a 911 call. But again, this requires 3Com phones and NJ200s installed throughout a company.Makers of IP PBXs with legacy PBX product lines mix old and new technologies to deliver e911. One option on Avaya and Nortel equipment links the ranges of IP addresses the IP PBX hands out to IP phones and to phone extension numbers in a database. When 911 is dialed from an IP phone, this data is sent to the PSAP via a separate ISDN line that is linked to the telephone provider's central office.Users adaptUsers with VoIP networks are adapting to e911 as best they can."Right now we're not doing anything with e911," says Gary Vandertoolen, network and telecom manager for the University of Utah Hospital (UUH) in Salt Lake City, where more than 700 3Com IP phones are deployed throughout several buildings.When 911 is called, the hospital's phones are configured to dial a university campus security office, which responds to emergencies and relays calls to local PSAPs for responding. 3Com NBX IP PBXs in each building register with the campus security office and give the 911 PSAPs building and address information.UUH is tackling the project of making the automatic availability of more detailed e911 information in parts."The way we're hoping to get this to work is that each one of our phones has a [media access controller] address that we'll tie to a [phone] extension," Vandertoolen says. "We're looking at some tools that will go out and pinpoint where each MAC address is physically located and show what switch port it is coming out of." UUH also deploys 3Com Network Jacks, which have MAC addresses that could be mapped to a phone's physical location.Because UUH uses Foundry Networks switches, Vandertoolen might use a Foundry tool for port tracking and creating network maps. A network mapping and MAC address tracking tool from InMon also is being evaluated, he says. Specific physical locations based on these maps - such as "second floor, east" - then could be transmitted to e911 PSAPs."It's something that we know can be done," Vandertoolen says of VoIP\/e911 support. "But we just have to find the resources and time to do it."The Nortel standardNortel this March proposed a standard to the FCC for standardizing the way e911 data is registered, and delivered to PSAPs over VoIP networks. The rough-sketch technology outline proposed the use of cell phone 911 location infrastructure, in conjunction with Dynamic Host Configuration Protocol (DHCP) servers in corporations, service providers and public premises that offer VoIP services.Many companies use specialized service providers or make agreements with their telcos to pass e911 location database data to PSAPs, says Mark Lewis, a senior consulting engineer at Nortel who is involved in crafting the VoIP\/e911 proposal."Those records often have to be loaded or faxed" to telcos or directly to PSAPs, Lewis says. "This is a manual process today."The Nortel proposal would borrow location database infrastructure from the cell phone networks' 911 system, which automates the delivery of e911 and location data to PSAPs, Lewis says.Cell phone network equipment uses routing keys with location information and geospatial tracking technology. When a 911 call is made from a cell phone, the number is matched to the location key that is sent to the PSAP, which gives responders a relative geographical reference for the caller.Although the details are still to be determined, the VoIP\/e911 system would have a DHCP server in a VoIP network register its location with a local cell phone switch. New devices to be added to the network - which Lewis describes as "location gateway servers" - would act as a relay between DHCP servers on VoIP networks and the cell network. This would allow the automatic updating and delivery of location information to PSAPs, Lewis says. He says Nortel is working with the National Emergency Number Association \u00a0to create a standard around this concept.Whether the Nortel proposal ends up as a standard depends on how the carriers, many of whom are slow to recognize VoIP, will accommodate."Carriers were supposed to have complied with e911 for cellular, but they are lagging behind what the FCC wants," says Ron Gruria, an analyst at Frost and Sullivan. "Enterprises take [e911] seriously because many have to have it."And for corporations to comply, it's still every man for themselves, he adds."There are lots of workarounds, but no standard way to solve this problem," he says.