Why use SIP for IP communications?

By Brendan Maree, Interactive Intelligence
Monday, 08 February, 2010


Interactive Intelligence’s Brendan Maree exhorts businesses thinking about implementing IP telephony to ask one question before anything else. Why use a network architecture based on the session initiation protocol (SIP) to support internet protocol (IP) communications? Or put it this way … they should at least take a look at the SIP open communications standard and do their homework on it.

It isn’t that an organisation’s IP telephony initiatives are destined to fail if they don’t incorporate a SIP-based network for any required migration up front and for long-term use thereafter. However, leaving SIP out of the mix can definitely diminish the level of IP success, as can an IP PBX phone system that stems from a traditional proprietary PBX hardware architecture not made for SIP-driven IP communications.

One reason most vendors in proprietary circles have yet to adopt SIP for their IP PBX hardware offerings is the SIP standard itself. SIP is software based, open and lightweight, and is designed to direct IP telephony calls to application servers on a data network the same way as emails, web chats and other media. Its inherent simplicity makes application interoperability much easier than hardware systems and older voice protocols such as ISDN, which are well known for system compatibility problems.

As industry analyst Gartner points out in its report - The IP PBX is a Potential Architectural ‘Dead End’ (April 2005) - many current IP PBX hardware products rely on a centralised proprietary IP architecture to replicate the digital model their PBX forefathers used a decade ago. Go back further in time and the 1990s digital model actually evolved from the proprietary PBX architecture model first introduced in the 1950s. With such a lineage of legacy thinking behind proprietary IP PBXs, it’s just as the analysts at Gartner so succinctly put it, in that proprietary approaches to IP communications “fail to leverage emerging internet telephony standards, and will not support a distributed and open telephony architecture.”

The result? Choose proprietary IP PBX hardware that can’t accommodate open standards and your choice of voice applications is limited to those offered solely by the proprietary vendor - or an approved affiliated vendor - effectively locking your organisation into that vendor’s IP solutions and no one else’s. Same thing if your business wants to integrate third-party communications applications, which the same vendor is only more than happy to do through a high-priced computer telephony integration (CTI) interface.

Given the software nature of SIP, the majority of new IP PBX systems now on the market are designed as standards-based software applications to fit SIP networks for IP telephony. Being software oriented aligns many of these IP PBX solutions more closely with the SIP model to support cost-reducing third-party IP phones and soft phones as well as mobile devices, desktop PCs and traditional analog telephones.

Adding business value

One of the beauties of SIP is the ability to integrate an IP PBX application server alongside data servers on a single network - and to administer them all from that same converged network environment. Don’t use a SIP architecture, however, and your business is left staring at The Great Voice and Data Divide from disjointed phone equipment and data systems and their equally disjointed administration.

Worse for your enterprise if it maintains multiple offices, bypassing SIP inhibits the ability to standardise technology across sites for users, desktops and customer features, which can lead to business process disparity from site to site, business continuity management issues and inconsistent service levels for customers, not to mention the expense of maintaining lines between remote office locations.

What SIP brings to the table

Imagine using a single IP PBX software server and SIP-supported network to drive a mix of voice applications such as live conferencing, instant messaging and other media. Imagine pre-integrating business applications that embed open standards for interactions generated from those same applications.

For instance, use a SIP network to implement IP telephony software from Interactive Intelligence including the company’s Microsoft-based IP PBX application suite for the mid-sized enterprise and it becomes an easy matter to pre-integrate Microsoft Windows Server System products such as Exchange Server, SQL Server and Office Communications Server 2007 - all out of the box. For organisations using the Microsoft Dynamics range of applications there are additional integrated innovations such as Interactive Intelligence’s IVR data access, integrated CTI screen pop and embedded client call controls.

The open architecture and application interoperability of SIP and IP telephony also offer reduced equipment costs. Up to 10 hardware boxes can be replaced with bundled software applications such as ACD, IVR, fax and voicemail. The use of standards introduces the possibility of third-party IP phone sets that sell for under $100 per device - less than a quarter of some of the proprietary alternatives.

SIP streamlines system administration. The IP PBX application can be integrated with systems for conferencing, unified messaging and other media on the same SIP network, eliminating the need for multiple administrative interfaces as well as the need for separate IT voice teams and data teams. Using SIP with a standard operating system and troubleshooting tools simplifies desktop and endpoint management enterprise wide.

Savings can also be made when choosing SIP-based carriers that use bandwidth for voice communications, rather than more expensive traditional TDM lines. Toll bypass cost reductions are another way to achieve long-distance savings.

SIP-based IP communications allow remote and mobile employees to stay connected full-time to the enterprise and to customers alike. Workers can hot-desk from virtually any office location, access the corporate communications system and mission-critical data at any time from wherever they are, and utilise multiple devices such as laptops, mobile phones or handheld devices based on their mobile login choice.

SIP for the bottom line

Recapping the question about why SIP is the best choice for supporting IP telephony, it’s safe to say the answer is a multi-benefit response that goes something like this: virtual company communications applications; user and endpoint applications based on user type; increased workforce accessibility and more efficient use of employee time; faster, more consistent service for customers; lower investment and maintenance costs for software over hardware; easier administration from a single voice and data network that fits an organisation’s Microsoft strategy; processing per office location and or department based on specific application requirements; no more business continuity concerns. Adding to the case of why SIP is the best choice is the all-important future-proof technology approach to SIP-based IP telephony applications that proprietary IP PBX hardware simply can’t provide.

It’s an impressive list and one that should make any organisation think twice when presented with the choice between a SIP-based future and a non-SIP-based, proprietary ‘architectural dead end’.

Interactive Intelligence has released the Interaction SIP Station, a communications endpoint device designed as a simple alternative to IP desk phones.

“While IP desk phones increasingly offer sophisticated functionality, their complexity and cost are barriers for adoption among many organisations,” said Drew Kraus, Research Vice President with Gartner. “Though the use of USB headsets with softphones offers an alternative, reliability issues often preclude their use. We’ve been telling clients for a while now to lower their infrastructure costs by deploying low-cost phones, while supporting advanced telephony features via PC-based call control applications. By further distilling that endpoint device down to its core functionality, organisations can realise even more savings while still maintaining a clear voice signal and advanced features.”

With a dedicated chip-set delivering quality audio, the Interaction SIP Station has no handset, display or dial pad. Instead, the device is designed to work in conjunction with a headset and the Interactive Intelligence Interaction Client, a PC-based call control software application that includes features such as call recording, call rules, conferencing, presence management, company directory look-up, queue monitoring and call history. It is targeted at mid-size to large contact centres and enterprises.

Brendan Maree joined Interactive Intelligence in 2006 as Country Manager for Australia and New Zealand. His main responsibilities include channel sales management as well as the daily operations for business management in both countries.

Maree started out his professional career as Account Manager at Anritsu, a Japanese-based provider of test and measurement equipment. Later, he joined Allen Telecom, a US-based mobile phone infrastructure provider, as its National Account Manager. He then moved on to become Director of Sales for MC Solutions, a mobile phone infrastructure group providing turnkey solutions for rail, road and buildings.

Prior to joining Interactive Intelligence, Maree was Avaya’s Channel Manager for SMB products, a position he held for two years.

Maree has diplomas in Telecommunications and Radio Frequency, which he gained during his nine-year tenure with the Royal Australian Navy.

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