An IP-PBX And CT Server Enable Smooth Internet
BY JIM MACHI
Today, youre closing a big deal. Youre looking feverishly for your lucky
pen the one you always use to sign contracts. You look everywhere, even moving the
phone, which is tucked into the corner of your desk. As you move the phone, you see a fat
red cable connected to the back. Theres no RJ-11 port. Whats going on here?
Whats going on is that youve been talking over an Ethernet cable since the
day you started at your new company, without even realizing it. Is the Internet
telephony hype getting to me? you ask yourself. Am I dreaming? You
thought Internet telephony (IPT) was really just about rate arbitrage opportunity and
free phone calls. While rate arbitrage opportunities have certainly been the
driving force behind the development of the IPT industry over the past three years, the
cost-of-ownership benefits IPT systems offer for both infrastructure and network
management are its real sustaining advantage. This is true for IPT in both the
public network and the enterprise.
WHY AN IP-PBX?
Traditional PBX vendors such as NEC, PC-PBX
vendors such as Comdial, and some newcomers such as
Selsius (now part of Cisco) have already demonstrated
and begun selling either pure IP-PBXs or IP-enabled PBXs that connect to
H.323-ready Ethernet phones. These phones look and act like the standard, proprietary,
digital, feature phone thats already on your desk.
What has driven the need for an IP-PBX? Companies like StarVox
have been selling IPT to the enterprise as an adjunct to existing PBXs, taking
advantage of intranets that had been set up between headquarters and remote offices before
IPT was even a dream. The installed PBXs work, and work well, so they are not going away.
Enterprises can, however, take advantage of rate arbitrage opportunities by installing IPT
gateways in each enterprise location to send both voice and fax calls over the intranet to
their own locations.
Fax is a big driver for IPT in the enterprise. About 70 million fax machines are in use
around the world, many in business environments. These fax machines exist, will continue
to be used, and are not IP-enabled. Approximately 40 percent of most corporations
telephone charges come from the cost of sending faxes. There is still a need to use these
fax machines as endpoints, and there is also a need to send real-time faxes (T.38 is the
real-time fax standard for H.323 environments). So, why the need for an IP-PBX?
It comes back to the infrastructure and network management cost savings. An IP-PBX
requires only one wire to the desktop. Since companies already need to install Ethernet
for computer connectivity, the MIS department can enjoy tremendous cost savings if it
doesnt have to install a separate voice infrastructure. Also, when Ethernet is the
only infrastructure needed, system management is much easier. The MIS department only
needs to manage the data infrastructure which can now carry both voice and fax.
While the PBX adjunct system certainly fills a large enterprise market need
especially for Fortune-2000-sized companies there is still a tremendous need it
doesnt fill. The IP-PBX is a great way for these companies to grow their
infrastructure and add capacity.
Say you are the MIS director of a company expanding into a new building. An IP-enabled
PBX would certainly be less expensive, from both an equipment perspective (the PBX and the
cost of each proprietary digital feature phone) and an infrastructure perspective. Using
this reasoning, small to medium-sized companies could start out with only an IP-enabled
PBX. While each of the IP-enabled PBX vendors mentioned earlier has H.323 phones to sell
with its PBX, H.323 fax machines are not yet available although they are on the
way. When H.323 fax machines enter the marketplace, IP-only PBXs may be able to replace
MEETING VOICE AND DATA NEEDS
Consider the voice and data network needs of a typical company. Most enterprises
have a proprietary PBX as the centerpiece of the voice network. There are also usually
adjuncts connected to this PBX, typically open systems-based computer telephony (CT)
systems. Each of these systems is a standalone server, with its application tied to the
computer-telephone integration (CTI) hardware (Figure 1).
Figure 1. Enterprise Media Today
Some of these systems may also be connected to the data network. For example, the fax
server is connected, since you may be able to send faxes from your desktop computer to a
fax machine at another location. Alternatively, the fax server may need to fax back a
document (stored on the data network) when a caller request comes into the fax server. If
you have an IPT voice/fax gateway, it is also connected to both the voice and data
network, bridging the two by converting one transmission medium to the other. Also, most
enterprises also have a remote access server (RAS), typically to accommodate employees who
need to dial in to the e-mail system, or who need access to a database.
Bringing together all the adjunct servers into one system (which is not as hard as it
might seem, since these servers are typically based on open systems), makes it much easier
to create applications and manage resources (Figure 2). Applications can
focus on their differentiating features instead of having to manage low-level resources.
The CT server software takes care of all underlying resource management, and the
application has no need to know the various voice inputs and outputs (for example,
digital, ISDN, analog, H.323, MGCP). It only needs to know that a call is to be made or
received. The type of signaling and the transport mechanism are transparent to the
application. The CT server means less work, and much more portability for application
providers. For example, a CT server application could automatically move into the IP
network world from a pure voice network world if a resource manager layer were there to
handle the underlying transport.
Figure 2. Multi-Application CT Server
Now, consider again the IP-enabled PBX scenario. If the CT server and the IP-enabled
PBX merge, all the voice needs of the enterprise are run from the CT server, which is now
very IP focused. This IP focus does not lessen the importance of the enhanced services
expected from the voice side. In fact, these enhanced services are just as important
if not more so in the IP world, since the compression algorithms make
features like play/record, fax, conferencing, DTMF detection, fax tone detection, caller
ID (even when coming in from the outside instead of intra-enterprise), and speech
recognition even harder. While a pure router gateway has its place, enhanced services are
a crucial part of the IP-enabled PBX.
So, if you are an MIS director, think how easy it would be to add a new employee if
your company had an IP-enabled CT server. Performing a single directory and administration
operation would provide all the phone and remote access services your new employee would
need. And if you are a new employee, or working in a new building, turn that phone around
to see what kind of connector is on the back. You might just be surprised.
Jim Machi is director of product marketing, Internet Telephony, for Dialogic
Corporation. Dialogic is a leading manufacturer of high-performance, standards-based
computer telephony components. Dialogic products are used in fax, data, voice recognition,
speech synthesis, and call center management CT applications. The company is headquartered
in Parsippany, New Jersey, with regional headquarters in Tokyo and Brussels, and sales
offices worldwide. For more information, visit the Dialogic Web site at www.dialogic.com