New PC spec boosts computer telephony
8/03/98
By Barbara Loonam
The telecommunications equipment industry is a $150 billion business today, but 90% of the trade is built on proprietary hardware and software architectures.
Over the past few years, however, multivendor PCs have begun to penetrate every sector of the telecommunications industry. While PCs have been embraced for applications such as voice mail, interactive voice response and IP telephony gateways, users have been hesitant to use PCs for such mission-critical devices as PBXs and switches within the central office of the public switched telephone network (PSTN). For while PCs offer many benefits, including cost-effectiveness, an open development platform and high levels of scalability, they have fallen short on offering high availability.
Enter CompactPCI.
CompactPCI is an evolving specification that defines how PC components should be built to ensure high availability and hot-swappable capabilities.
For our purposes, high availability means keeping systems running by decreasing downtime during routine maintenance operations and system failures.
High-availability systems differ from fault-tolerant systems, which use redundant hardware and proprietary software to provide nonstop operation. While not guaranteeing 100% uptime, high-availability CompactPCI systems provide an improvement in service over conventional computer systems.
A number of companies are now collaborating to define how the CompactPCI specification will be implemented and deployed in telecom platforms. Other groups are looking at how to integrate the Enterprise Computer Telephony Forum (ECTF) H.100 bus and provide telecom I/O through the CompactPCI backplane.
The Telecom Interest Sub-Committee (TISC) of the PCI Industrial Computer Manufacturers Group (PICMG) was formed in April 1996. TISC's purpose was to extend the capabilities and utility of the CompactPCI system architecture to support the application needs of the computer telephony industry.
The TISC document provides CompactPCI system vendors and computer telephony board vendors with specifications that define multivendor interoperability and support the design of open standards-based components and systems.
Key features include the H.110 backplane time-division multiplexer bus, which incorporates the ECTF's H.100 bus and hot swap; rear-panel analog and digital PSTN connections; telco power and ground; physical keying of boards; and board and shelf addressing.
The TISC collaborative effort has resulted in a rugged industrial chassis with well-established mechanical specifications that provides all of the advantages of a hot-swap industrial computer chassis while retaining compatibility with all desktop PC software.
Reducing downtime
The other major idea behind CompactPCI development and deployment is to reduce downtime in any telecommunications system. Users need to be able to replace network interface boards and digital signal processor adapters while the system remains up, or "hot." Until recently, this support was not available on PCI boards or with the Windows NT or Unix software platforms. Now there are two initiatives, PCIHot Plug and CompactPCI Hot Swap, to provide this capability.
The PCI Hot Plug specification defines the requirements for hot insertion and extraction of conventional PCI boards in server systems. Led by Compaq, the hot-plug initiative has achieved broad support from major operating system vendors, including Microsoft and Novell. Compaq and other chassis vendors are currently shipping hot- plug systems.
Hot swap defines a process for inserting and extracting boards without adversely affecting a running system. Hot-swap capability is essential during maintenance of a highly available system, but it is even more important for implementing the inevitable adds, moves and changes.
Additional work is under way to leverage the Hot Plug effort into the hot-swap technology defined in the CompactPCI Hot Swap specification.
CompactPCI Hot Swap is the latest specification for PCI-based industrial computers, and defines many features that make a PC more available. The Hot Swap subcommittee within the PICMG is working to extend the CompactPCI specification to include support for hot swap. The PICMG consortium is hashing out an extension to the standard that will let users mix and match CPU boards and backplanes from multiple vendors.
The CompactPCI Hot Swap specification is currently in final draft and is being reviewed by members of PICMG.
The arrival of CompactPCI is enabling telecom service providers to deliver new, innovative services with the reliability the telecom network requires. Companies deploying CompactPCI-based high-availability platforms will be able to meet the telecommunications infrastructure market needs for intelligent network integration, including service nodes, service control points, signal transfer points and Signaling System 7 gateways.
There is also a large demand for cost-effective, high-availability wireless CompactPCI PC packages such as wireless local loop, cellular/personal communications services/personal communications network, trunked radio and in-building wireless PBX systems. Additionally, new alternate access carriers are looking for cost-effective ways to provide telephony to the home and provide a variety of central office-grade enhanced services.
Loonam is product marketing manager at Natural MicroSystems of Framingham, Mass., a provider of telecommunications equipment. She can be reached at Barbara_ Loonam@nmss.com.
