Issue 71
SPEECH!
LET'S TALK ABOUT
THAT--OVER IP
By William Flanagan
We've heard much more
interest expressed lately about IP telephony,
a/k/a Voice over Internet
Protocol (VoIP). Trials or tests have
appeared
almost everywhere. One
large client found thousands of IP phones
installed locally,
without central coordination, producing islands of
incompatible VoIP
systems. It's deja vu all over again, something like
the inexorable spread of
the first PCs or how fax machines and cell
phones became essential
to business.
How are you coping? Let's
talk about that, and what others are doing in
the VoIP arena.
With this issue,
ViewsLetter shifts focus from high availability
services to VoIP. HA is
still a factor--the telephone has a very high
expectation for
availability, traditionally called "five nines" or
99.999% uptime (down
about 5 minutes a year). But moving from time
division multiplexing
(TDM) to packet switching for voice (VoIP)
fundamentally changes how
that goal is achieved (if it is achieved at
all).
"Telephone people" need
new knowledge and skills to stay on top of
telephony infrastructure
in the future. PBX makers stopped development
on legacy TDM equipment
so eventually everything will be VoIP on packet
networks. "Data people"
who have experience in IP on Local Area
Networks
(LANs) and wide area
transmission also need to expand their knowledge.
They may not know the
details of voice switching applications,
signaling, or
interactions with the global Public Switched Telephone
Network (PSTN).
Consider troubleshooting
voice quality on VoIP. The problem could
involve an application, a
server operating system, switches and routers
on a LAN, a wide area
network (WAN), firewalls, and those little
computers called IP
phones. Not easy to sort out, but future
ViewsLetters will cover
best practices, lessons learned, and the latest
tools of the trade to
help you do it.
Because we're technical
gurus, many issues will look at the hardware
and
software, at
configurations and network architecture, and how to make
it
work well. But the
business aspects won't be ignored. We'll examine
various claims for VoIP
in the area of cost reductions (often hard to
realize) and increased
features and functionality (which may take more
work than expected to
convert into greater business efficiency). Again,
there are practices and
lessons that should be of value to you.
Security is important to
both technical staff and management, so we'll
spend a lot time on this
topic. In addition to the vulnerabilities of
generic servers and
networks, VoIP brings in a new set of difficulties
for system operators. For
example, the problems associated with VoIP
connections crossing a
firewall are many (randomly assigned UDP ports,
for just one), with many
possible solutions.
VoIP is changing very
fast. The Session Initiation Protocol (SIP), the
format that is winning
the race against H.323 and proprietary
signaling,
has 50 or more study
groups working on extensions to deliver additional
features. The many Forums
are working on new standards and updates that
will impact buying
decisions in future years. We'll be watching what
they're up to and report
often.
Stay tuned for answers.
We're here to help.