February 1999
CompactPCI - The Open Road To Internet Telephony
BY POCHENG SHYU
While open systems continue to make inroads in practically every area of enterprise
computing, it's ironic that the comparatively new area of Internet telephony has remained
one of the last proprietary system strongholds. Now, due to the evolution of open bus
architectures, this is rapidly changing.
It's not as if the pros and cons of open versus closed systems aren't clearly defined.
Proprietary systems are plagued with significant footprint issues, and upgradability
problems abound. Exorbitant long-term costs, limited product choice, and all the other
negatives that revolve around vendor lock-in combine to paint a decidedly negative
portrait of proprietary solutions. Once you commit to a proprietary system, you are
committed to dealing with these negatives for a long, long time.
The open systems side presents a much more attractive picture. You can source from
multiple vendors and select from a wide variety of computing platforms and widely adopted
operating systems. Vendor lock-in is virtually a non-issue, and both immediate and
long-term costs are considerably lower as a result. Integration with other enterprise
systems (which are also increasingly likely to be open) is considerably easier, while easy
upgradability is central to the open system paradigm.
OPEN SYSTEMS GAIN TRAFFIC
So why haven't lower-cost, more flexible, off-the-shelf PC-based systems overthrown
proprietary solutions from the Internet telephony space? It largely comes down to a matter
of bus architectures. You need to base such systems on a robust architecture capable of
providing telephony's requisite reliability and scalability. The industry standard PCI
local bus architecture provides all the benefits of using low-cost PC silicon including
compatibility with thousands of PC software programs. Yet it does not make up for the poor
thermal features, inadequate shock and vibration characteristics, and difficult
serviceability of PC-based equipment - problems that most proprietary solutions are
designed to avoid entirely.
One possible solution would be to take a page from embedded industrial applications,
many of which are based on the VME bus architecture. VME, which is excellently suited for
real-time applications, has reigned as the leading industrial bus architecture since 1984.
While there is little question of VME's robustness - much of which is due to its Eurocard
form factor - it has only a limited presence in the telephony marketplace, and is
primarily found only in telephony central office applications.
A much more viable solution for Internet telephony can be found in the CompactPCI
architecture. Though a relative newcomer, the use of CompactPCI is growing explosively,
particularly in telecommunications markets. One of CompactPCI's biggest advantages for
Internet telephony is that it is PCI's industrial computing extension. It delivers PCI's
true processor independence (i.e., best silicon support), direct access to low-cost PC
components and peripherals, 132 Mbps bandwidth for each bus segment, and a wealth of
plug-and-play PC software. Applications can be developed on PC systems and then deployed
unchanged on CompactPCI - something that can't be done as easily on proprietary systems.
The other major advantage of CompactPCI for Internet telephony is what it has borrowed
from the venerable VME bus - namely industrial-strength reliability. CompactPCI uses VME's
proven Eurocard form factor and adds several key embellishments to make it a particularly
attractive architecture for mission-critical telephony applications. This, combined with
its open PCI heritage and support for multiple hardware platforms, has led CompactPCI to
be widely supported by all major telephony application vendors. As a result, there is no
lack of cost-effective, off-the-shelf solutions waiting to be deployed on CompactPCI
systems.
GOING THE EXTRA MILE
CompactPCI is designed to extend the advantages of the off-the-shelf PC model into
critical environments such as Internet telephony. Up to seven CompactPCI slots can be
designed into the primary PCI bus and multiple independent backplanes can be supported.
This allows for considerably more expansion than the three slots typically supported by
standard PCI bus technology.
In addition, CompactPCI implementations are based on a passive backplane configuration.
When a CompactPCI card is removed, there is no significant impact on the rear I/O
connections or on neighboring cards. Nor is there any internal cabling for card,
motherboard, and other peripherals, so servicing is much easier. The CompactPCI controller
is one slot on the CompactPCI bus, and is thus easy to pull out and replace when making
repairs or when upgrading the system. Hot swapping of expansion cards is also supported,
which dramatically decreases the downtime of an Internet telephony application.
CompactPCI cards are designed to work in a standard 19" rack, featuring
front-panel insertion and removal, and front or rear panel I/O functionality. Their shock-
and vibration-resistant Eurocard format supports CompactPCI's extensive "board
keying" capabilities (up to 4,096 combinations), while card guides ensure rear
backplane connector alignment. Unlike the chassis configuration used by most conventional
PCs, the Eurocard format ensures an even airflow and minimizes the danger of heat buildup,
which is, of course, a leading cause of board warpage and mechanical problems. Also,
unlike standard PCs, CompactPCI implementations use rugged 2-mm hard metric pin and socket
connectors (ANSI IEC-1076) designed for use in telecom equipment.
Finally, CompactPCI's 6U (long card) form factor provides a higher degree of I/O
functionality, a larger number of I/O ports, and more I/O pins than standard PCI-based
systems.
A BUS THAT DELIVERS
Companies looking to implement robust open Internet telephony solutions today will find
highly expandable CompactPCI systems available from several vendors. Systems can be
configured using off-the-shelf cards and peripherals to suit a variety of applications -
from call centers and T1 applications to Internet telephony gateway platforms and
voice/fax over IP. These solutions can be based on a choice of the most popular hardware
architectures, including Pentium, SPARC, and PowerPC. CompactPCI also supports MIPS,
Alpha, and a variety of specialty microprocessors.
It is also possible to implement CompactPCI solutions with an integrated
industry-standard H.110 computer telephony bus. H.110 on CompactPCI provides seamless
interoperation of components by facilitating time division multiplexing directly on the
system backplane.
Companies can easily build an application-ready system on this base using off-the-shelf
components, with very little in the way of engineering design cycles and costs. For
example, high-density dual backplane systems are already on the market to provide up to 14
6U CompactPCI expansion slots with an integrated H.110 bus. CompactPCI cards are readily
available from leading vendors such as Dialogic and Natural MicroSystems to populate these slots and complete a
multiple-resource system. An easily assembled basic configuration would include a voice
encoder board, T1/E1 telecom board, and an IP network board to connect a LAN or WAN. A
more complete Internet telephony system can add additional off-the-shelf components such
as a real-time fax over IP board, an ATM or frame relay board, an automatic speech
recognition or voice response board, and more.
Unlike open systems based on the standard PCI bus - or on ISA or EISA bus architectures
- these systems inherit CompactPCI's innate higher availability characteristics.
CompactPCI's hot-swap feature and front serviceable card cage minimize mean-time-to-repair
(MTTR) by allowing maintenance personnel to easily remove and insert cards without taking
down the system. Some CompactPCI systems on the market also feature hot-swappable fan
trays, hard disk drives, and redundant N+1 power supplies to further increase uptime. Some
have even been built to meet stringent Bellcore NEBS Level 3 criteria in order to support
critical telephony applications that must keep functioning in the face of earthquakes,
fire, lightning, power faults, and other natural disasters.
CONCLUSION
The robustness and high availability that CompactPCI brings to open systems solutions
makes it an easy choice for deploying Internet telephony applications. Not only does it
provide reliability characteristics that are in line with proprietary solutions, but it
also places Internet telephony implementations on the PC price curve. Implementations gain
from increasingly lower-cost, higher-performance silicon and widely supported operating
systems. Off-the-shelf boards are available for a wide range of applications, and major
vendors are introducing new boards with new functionality at a steady rate. Off-the-shelf
software is also readily available. And custom application software can be developed on
desktop PCs using popular programming tools, and then run without modification on
CompactPCI systems.
Change comes quickly in the Internet telephony arena. Open systems are much better
geared for both evolutionary and revolutionary change than are proprietary solutions.
Plus, they integrate better with other open enterprise systems. Until recently, the open
system challenge to proprietary systems in the Internet telephony space has been carried
by traditional PCs. Now, by extending the cost-effective, flexible PCI bus architecture
for critical applications, CompactPCI presents proprietary Internet telephony solutions
with a genuine challenge that they will find increasingly difficult to counter.
Pocheng Shyu is a product line manager at Force Computers. Force, a Solectron
subsidiary, is a leading designer and supplier of open, scalable system and board level
computer platforms for the embedded market. A processor independent company, Force
delivers products based on SPARC, Pentium, and PowerPC technologies. Force has been a
leading supplier of CompactPCI products since 1996, and is also the second largest
supplier of VME computing platforms. For additional information, visit the Force Web site
at www.forcecomputers.com. |