Salaries for networking and telecoms specialists with SIP skills
are high
What is it?
The key to soft telephony, instant messaging and much else, Session
Initiation Protocol (SIP) is used for setting up communications
sessions between devices on the internet.
SIP is a lightweight client easily embedded in end-user devices,
including PCs, personal digital assistants and 3G phones, enabling
them to communicate with and provide services to other SIP-enabled
devices.
Early adopters concentrated on internet telephony - voice over IP -
but quality and reliability were poor and traditional telecoms
companies, seeing their infrastructure investment threatened, were
resistant.
Now telecoms companies such as Siemens and Nortel are in the
vanguard, along with Cisco, Microsoft and a host of start-up
companies. Issues such as quality of service and security are being
tackled and applications are becoming more sophisticated.
Where did it originate?
SIP was developed in the mid-1990s with a structure based on SMTP
e-mail. It was taken over and standardised by the Internet
Engineering Task Force in 1999.
What is it for?
SIP telephony applications include conferencing and combined voice,
video and graphics. SIP Instant Messaging and Presence Leveraging
Extensions (Simple) defines how SIP should be used for instant
messaging, enabling different suppliers' implementations to
communicate with one another.
Much current research is into "presence" applications, using an
event monitoring and notification mechanism which alerts people
when a user is at their desk, re-routes calls to their mobile phone
when they are out, or begins a conference automatically when all
participants are available.
What makes it special?
SIP is a potentially universal standard which is
simple to work with and easily extensible to accommodate new
applications and communications media. It is not dependent on the
infrastructure and exchange services used by traditional telephony.
Instead, SIP-enabled devices communicate directly with each other,
making use of any available path, and relying on the web's domain
name service to find any device by its unique IP address.
SIP components can be easily commoditised and distributed. Analyst
firm Gartner said, "Enterprises that adopt SIP in their
architectures should be able to be more selective with
communications applications from different suppliers." However,
this depends on suppliers sticking strictly to the standards and
commercial developments rapidly outstrip the standards-setting
working groups.
How difficult is it to master?
SIP is a simple protocol but its applications can be complex.
People already working in networking or telephony can learn the
essentials of SIP in two days.
Where is it used?
Most applications are within organisations, although telcos that
see their traditional voice markets threatened are developing IP
telephony services. Much work needs to be done on privacy, security
and related issues before presence-based commercial services are
rolled out, if these are not to become intrusive and
disruptive.
What systems does it run on?
SIP is being built into Windows XP and Messenger and
Cisco's gateways and servers. Phone manufacturers such as Nokia
offer downloadable SIP development kits.
What is coming up?
Work is being done on SIP security and reliability,
but there is a long way to go before the 99.999% uptime expected
from conventional telephony.
Training
Training is available from major manufacturers and their partners
and independent IP telephony specialists
www.hn-networks.co.uk
www.voicom.co.uk
www.mpirical.com
Rates of pay
Roles requiring SIP include voice over IP engineers, digital
communications software developers, network support and contact
centre staff. Salaries in this fast-moving sector are high.