Nortel puts intranet telephony onto PBX

By David Rohde
Network World Fusion, 7/15/98

Continuing its IP catch-up game, Northern Telecom, Inc. has announced that by year-end it will offer an IP telephony trunk on its PBXs.

On Monday, Nortel unveiled the Meridian Integrated IP Telephony Gateway, an eight-port trunk card for its flagship Meridian 1 PBX. The card, loaded into a Meridian peripheral module that supports line and trunk cards, provides a 10-Base-T network interface to a corporate intranet.

Corporate network administrators can then route some of their voice traffic over the intranet, just as they now route voice traffic via the PBX to dedicated or switched access trunks reaching their long-distance and local carriers.

With the Integrated IP Telephony Gateway loaded on the PBX, individual end users do not have to dial any extra digits, as they typically do when using an IP carrier's service. "It looks to the Meridian 1 like any other trunk card," said Ann Swenson, product marketing manager for the new offering.

Administrators also have the ability to set parameters in the Meridian's routing tables to determine under what conditions voice traffic will flow to IP telephony. For example, individual end users' stations can either be authorized or not authorized to dial over the corporate intranet, just as traditional PBX routing schemes can block individual users' ability to make international calls, Swenson explained.

A key feature: Before sending traffic over the intranet, the PBX will test for dropped packets or excessive latency. The exact levels can be set by network administrators, but Swenson suggests a maximum delay threshold of 150 milliseconds one-way. If delay exceeds that level, the call falls back to the public telephone network. Swenson discourages use of the gateway to send voice traffic over the public Internet.

The network-testing and fallback features are also available from Nortel's principal PBX rival, Lucent Technologies, Inc., for the IP trunking option on its flagship Definity PBX introduced earlier.

Nortel's scalability will be limited at first, because the IP telephony card can only support eight simultaneous phone calls. Nortel is working on a denser port card with up to 24 ports. However, users can install multiples of the eight-port card depending on available space in their PBX trunk modules, Swenson said.

Nortel is still working up a final price for the Integrated IP Telephony Gateway, pending trials that begin next month. Swenson said the target price will be no more than $7,500 per card for the eight-port configuration. An initial beta user -- Meridian user and semiconductor maker LSI Logic Corp. -- believes it can achieve end-to-end toll quality by combining the Integrated IP Telephony Gateway with its enterprise IP WAN, according to Scott Clayton, LSI's manager of global network engineering.

Up until now, most of Nortel's toll-bypass work has centered around ATM, not IP. Users of Nortel's Magellan enterprise multiservice switches have the ability to interleave voice traffic onto variable-bit-rate ATM paths, thus avoiding the need to either use a carrier or nail up a private circuit for a phone call.

Nortel's Micom division does offer an external voice-over-IP gateway called the V/IP, but analysts have said that many users are looking for a packetized-voice offering completely integrated and manageable within the PBX. Meridian users must have Release 21 of the general Meridian PBX software to employ the Integrated IP Telephony Gateway.