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Making the Vall on VoIP: Page 3 of 8

Lexent had chosen the router-to-firewall approach initially because the PIX firewall provided fail-over redundancy at headquarters, and having one box do two jobs was easier to manage. "If we hadn't done any voice, we would have been able to go router to firewall," Arduini says.

Lexent's VPN runs on a 100-Mbps Ethernet backbone at the company's downtown headquarters and 256 Kbps or full T1 to its remote sites, including Garden City, where the Hicksville office recently was moved. An important component of Lexent's strategy has been the redundancy of the VPN, voice equipment included: "We have two of everything at headquarters and a mirrored configuration at our disaster-recovery site, plus a backup ISP," Arduini says.

The company is using traffic-shaping features in its Cisco routers to make sure voice gets priority and its carriers don't drop voice packets. "We make sure we drop data packets up front," Haluza says. The traffic shaping ensures that its heavy data applications, which include engineering files and aerial digital photos as large as 40 MB, don't interfere with voice traffic.

Single Message Box

Cisco's Unity Unified Messaging (UUM) is the main application Lexent is running with the VoIP system. The company's Microsoft Exchange mail, voicemail and faxes are integrated, so a user can pick up voicemail, e-mail and faxes from an office line, cell phone or e-mail box. A user also can forward voicemail and faxes to other offices. UUM runs on the Cisco Call Manager server.