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In the electronics and technology industries, the commercial and defense sectors have had a long history of leveraging R&D and technological advances across sectors, with the eventual implementation and/or commercialization of numerous applications.

The commercial off-the-shelf (COTS) movement, which gained popularity in the 1990s, further demonstrates how the commercial and defense sectors have played off of one another when it comes to emerging technologies. Session initiation protocol (SIP) may well be the next COTS technology that finds its way into military applications. Because it's a standards-based signaling protocol, it provides a universal communications language; a lingua franca based on the Internet protocol. It is an ideal and secure means to integrate real-time and enterprise-like datastreams into single, converged solutions for interesting and innovative applications. The military and defense communities may be well served to take its cue from the carrier and enterprise world, where SIP is being rapidly adopted as the platform-of-choice to enable an advanced set of next-generation applications and services.

The Internet protocol (IP) has been the standard in data networking for nearly a decade, and has become a major driver of innovation in the telecommunications industry over the past several years. Voice network operators have recognized the potential cost savings of IP networks over their legacy counterparts, and IP is now overtaking the lead in terms of voice lines installed on a worldwide basis.

As service providers have faced increased competition in recent years, IP has offered an attractive way to reduce costs and deliver improved operating results. Yet, driving cost out of the equation is only part of the value that IP has delivered to operators and end users. IP has also provided an efficient way to deliver voice, video and data services to end users across multiple networks and an array of devices from mobile phones, to smart phones, to laptop computers. This includes software-based IP conferencing (Figure 1). IP has enabled a new and improved communications experience that has not only reduced the cost of service for operators, but has introduced an opportunity to develop and deliver new services that can be further monetized.

Perhaps the most important aspect of IP is its security feature. IP can provide end-to-end encryption over public data networks so conversations and transactions remain secure. IPSecurity Encryption (IPSec), for example, uses an Internet key exchange (IKE) technology that assures secure sessions over public networks. Similarly, VoIP and converged data based on SIP can be made secure using proven enterprise security measures, such as using an encryption technology to protect VoIP conversations, and deploying a SIP firewall/secure edge proxy firewalls at the edge of the enterprise to filter incoming VoIP traffic.

For defense and military applications, IP provides not only the same cost benefits as realized in the commercial world; it also provides a secure method of communications and networking. It can traverse multiple network types, from optical to wired to wireless, making it particularly suitable for command and control as well as battlefield operations.

The groundwork has already been laid for commercial IP-based communications technologies to be adopted in the defense sector. To ensure interoperability with the defense switched network, the U.S. Defense Department's Joint Interoperability Test Command (JITC) conducts certification testing and is required for all products that support data or video communications connecting this secure network. The JITC certification process, coordinated by the Defense Information Systems Agency (DISA), entails an arduous regimen of system and interoperability tests. JITC certification ensures that products are secure, operate without performance degradation in a multivendor environment, possess exacting levels of resiliency and redundancy to ensure reliability under duress, and offer the unique military features and functionality required for national security. Several nationally recognized providers of IP communications equipment — from Cisco to Harris Corporation to Nortel Networks — have been awarded JITC certifications. These arduous processes and certifications support the case of IP communications being used in the defense world, and potentially their move into command and control applications.

Session initiation protocol (SIP) is an application-layer control (signaling) protocol for creating, modifying and terminating multimedia sessions with one or more participants. The primary intent of SIP is to provide a signaling and call setup protocol for IP-based communications that can support a superset of the call-processing functions and features present in a typical telephony network with PSTN termination. Multimedia, in this context meaning voice, video and data all being transmitted and available within a single call or session, is an important aspect of SIP's capabilities. It is a true multimodal protocol. Furthermore, SIP enables the session to be shared among numerous participants, so multiple people can participate in the same call or session in real time.

SIP, a text-based protocol that uses UTF-8 encoding, is often compared to HTTP, the Web protocol, or SMTP, the simple mail transfer protocol. SIP messages consist of headers and a message body. SIP message bodies for phone calls are defined in session description protocol (SDP). SIP can use UDP, TCP and other transport protocols. SIP can be viewed as the enabler protocol for telephony and voice-over IP (VoIP) services, of which the following features play a major role in the enablement of IP telephony and VoIP services:

• Name translation and user location: Ensures that the call reaches the called party based on the user's location information.

• Feature negotiation: This allows the users involved in the call to agree on the features supported.

• Call participant management: Participants can bring other users onto the call or cancel connections to other users. Users could be transferred or placed on hold.

• Call feature changes: A user can change the call characteristics during the course of the call (e.g., enabling video stream).

• Media negotiation: Negotiates and selects the appropriate codec for establishing a call between the various devices (common denominator).

SIP provides a perfect platform for integrating real-time communications, such as IP telephony or VoIP, through a Web-services or service-oriented architecture (SOA) framework. This opens up interesting possibilities for new applications where voice, video and data converge.

Ubiquity Software, for example, has created a carrier-class SIP application server (Figure 2) that decouples the SIP server and runtime environment from the application itself, which means developers can become proficient in a single platform environment and develop different types of applications that work across multiple networks and platforms. Figure 3 shows a SIP-based SOA, which also makes it easier to integrate with existing applications and services via Web services, and repurpose those application building blocks to create new services. The SOA leverages a set of pre-built service components in the form of software objects that represent discrete functionality within the application. These software objects can be easily modified, customized or updated, or even repurposed into new applications with-out rewriting the entire application. This SOA methodology simplifies and streamlines application development, testing, deployment and maintenance. For commercial carriers, this means they can “fail fast,” testing the commercial viability of new services with less investment. For defense applications, it means customized, robust SIP communications can be quickly created for a specific need or scenario.

Additionally, a standards-based instant messaging protocol based on SIP called SIMPLE is under development in the commercial world that builds on the robust multimodal capabilities of SIP. SIMPLE can carry presence information, conveying a person's availability and ability to engage in communications. Presence information is most recognizable as “buddy status” in IM clients like Yahoo Messenger and MSN Messenger.

With the powerful combination of voice, video and data all being available within one converged application, combined with presence information to indicate who is available to collaborate at any given moment in time, it is reasonable to anticipate some interesting commercial and defense application scenarios.

SIP has become the de facto standard for delivering VoIP services in the carrier world, with everyone from AT&T to Vonage offering a VoIP solution. But SIP is quickly moving downstream to serve as the foundation for converged multimodal applications.

Conferencing in the commercial world is undergoing a strategic transition, moving from a hardware-based solution to an IP-based software model. Many carriers are in the process of switching their legacy conferencing infrastructure over to IP, and more specifically SIP. In the initial phases, the features mirror what has been the norm in the legacy world — basic audio conferencing with some basic administration features for set up and organization of conference calls. Although there is only a subtle difference in these new IP-based solutions, there is a huge strategic difference.

With an IP-based architecture established, and SIP-based audio conferencing application developed, tested, and moved into production, a new feature or combination of features are relatively easy to add. For example, the following features can be added to basic audio conferencing:

• Web interface: a web interface feature can be added to control the conference call from a standard web browser.

• User and group lists: to support easy setup of conferences, the system can access corporate user and groups lists from a central database.

• File sharing: documents and other content can be shared with the attendees within a conference, allowing the users to access these resources via a web browser.

• Multimedia streaming: Flash, MPEG and WAV files can be played within a conference.

• Video: the ability to videoconference can easily be added as a capability.

• Click-to-conference: a conference can be launched from a simple text-based hyperlink within an e-mail, document or even an instant message (IM) session.

From the features listed above, a basic audio conferencing system can be transformed into a robust application that incorporates voice, video, data, presence, web services, and more. To address the question of whether SIP can be effective in defense and military applications, it is necessary to explore several scenerios.

Reconnaissance missions would be the ideal application for SIP-based communications. A reconnaissance team could be sent out in advance of a combat mission to gather intelligence on the enemy, their position, their artillery and weapons capabilities, and other critical factors for planning military operations. A reconnaissance aircraft could be equipped with an IP-based communications system that allows the wireless transmission of photographs, streaming video and other critical data back to a central command and control base to be shared with military planners and discussed in real time. GPS information could also be captured from the aircraft's position, and any collected intelligence could be automatically documented and cross-referenced to the precise location. The crew of the aircraft could be conferenced in with the command center and other relevant parties, perhaps even a commander or other experts at the Department of Defense. Before the reconnaissance mission was ended, the parties could discuss the intelligence to ensure that all critical information had been obtained and verified, transmitted and stored in a secure database. This application would limit the number of soldiers required for a mission, and reduce the requirements for subsequent follow-up missions.

Consider the following scenario. In a battlefield situation within an urban setting, an advanced ground brigade unexpectedly encounters what they believe is an insurgent force, and is uncertain about the engagement policy and the identity of the subjects in question. Let's assume that the ground brigade is a U.S. Army troop that is part of a multinational team comprised of various forces from different countries. Before the troop engages, they must conclusively identify the subjects in question, and then coordinate with other troops in nearby areas for backup and tactical coordination and execution.

In this battlefield scenario, all of the ground troops presumably would be armed and equipped with SIP-based, helmet-mounted video cameras and SIP-based phones that connect over IP to the defense switched network (DSN), which also connects to central command and control as well as the Department of Defense. In this scenario, the advance brigade would stream video of the target within a SIP call to the command and control post for identification, and to the adjacent brigades for coordination of possible offensive operations. The two brigades and the command and control center are conferenced together to discuss the evidence, and determine that further direction and authorization must be obtained.

Based on presence information that the command and control center has displayed from their system, they can see that the Secretary of Defense, 12 time zones away, is not available to confer on this situation. However, in this case, the system does show that the Assistant Secretary is available, and has the authority to authorize the appropriate action. The Assistant Secretary is then bridged into the conference. Upon review of the evidence, the decision is made to escalate the call to a Special Operations unit that has expertise in the identification of local insurgence groups. The Special Operations team is bridged into the call, and the Special Ops group identifies the insurgent group and advises the ground brigades on the size of the faction, their typical weapons and artillery capabilities, and their methods of warfare. The call is concluded with the Assistant Secretary authorizing an offensive operation that involves both ground brigades, with the U.S. Army troop taking the lead. This application leverages SIP-based video, voice, presence and IM to share graphical information in real time, and to immediately and intelligently review and act on that information. SIP is a technology that is proving itself in the commercial world as an enabler of new multimodal collaboration applications, from video conferencing, to picture sharing, to intelligent call routing. At a fundamental level, any application that combines real-time communications such as voice and video services with data, is suitable for exploitation by SIP. SIP provides a strategic platform (Figure 4) on which new proof-of-concept applications are rapidly being developed, evaluated and produced (if they prove successful and viable). SIP also provides an ability to accelerate this process. SIP provides an inexpensive and practical way to create new applications with a standards-based approach that ensures interoperability across mediums, networks, and devices. SIP is an emerging technology that embraces best practices for application development and integration of new applications into IP networks.

While these are hypothetical application scenarios, they illustrate the potential for SIP to be used to bring context and a higher-level of intelligence to military and defense communication systems. They also illustrate how more intelligent systems can increase the success of critical operations across multinational forces, and how real-time communications can change the ways in which wars are waged. By equipping the ground forces with multimodal communications, new strategies could be applied to keep expertise away from front-line situations while, at the same time, harnessing their expertise. At the end of the day, more intelligent welfare strategies protect troops, potentially save lives, and increases the odds for success. It may very well be that SIP has an important role to play in next-generation defense systems.

Gary Gray is senior director of corporate marketing for Ubiquity Software, which develops carrier class communications platforms; integration technology and development tools based on the open session initiation protocol (SIP) for converged voice, video and data services. He holds a degree in communications from Florida Atlantic University.