How to Reduce Time-to-Market for Triple-Play Telecom Products using Media Processing Development Tools
Overview VoIP is finally moving from the early adopters market to the mass market. Video is becoming the next “killer application,” as evidenced by its wide adoption by the 3G market. This trend brings Video into the home, office and contact centers. VoIP is Not Only Voice Users want to have a single device provide features such as: real-time Voice and Video, Video streaming, Video mail retrieval via the device or e-mail, and enhanced Presence capabilities that will be integrated with location-based services. It should provide information about the availability of each person to which he has access—and Messaging. Providing these services in a cost-effective and high quality manner requires seamless roaming of the device between the different networks, and service availability across the networks. This requires: 1. Bridging between the following networks: a. Broadband Wireline IP network, mainly using SIP but also using legacy H.323 equipment b. Broadband wireless IP network (WiFi and WiMAX) using SIP c. 3G real-time conversational Voice and Video, currently using 3G-324M and SIP in the future d. Voice PSTN network e. Video over PSTN using H.324 2. Connectivity between devices in these different networks is crucial. Even when both devices support SIP, media bridging/processing may be required. Off-the-Shelf Media Processing Solutions vs. Solutions Developed In-house The manufacturer needs to decide whether to use available off-the-shelf solutions or to develop an in-house solution when designing and planning new Voice and Video infrastrustures. Solutions include: 1. In-house only This requires more than 25 R&D years to develop the required software components: a. A complete DSP framework b. Voice codecs, including the required Voice features. c. Video codecs, including Video processing features. d. Development of other media types, such as Fax and Modem. An optimized DSP farm board must be developed, a task which requires significant R&D resources. This board would typically be a PTMC or AMC daughter card that rides on a cPCI or ATCA motherboard. The manufacturer would need to purchase an off-the-shelf motherboard and perform the required integration work, or develop this component from scratch. 2. DSP software / DSP fully-loaded with software This solution includes the DSP framework as well as the media types that run on it. Choosing this level of integration requires a significant investment in both development of the DSP farm board, and integration or development of the motherboard. 2. A complete off-the-shelf DSP farm solution This solution comes pre-integrated with a motherboard and includes all the components described above. This results in greatly reduced time-to-market. And maximizes the added value of the manufacturer’s application, providing competitive differentiation and the reason for customers to buy the end product. Regardless of the actual development approach chosen, the following decisions must be made: 1. Choosing the DSP farm board architecture 2. Choosing the media processing software architecture 3. Choosing the DSP Choosing the DSP Farm Board Architecture A DSP farm board needs to handle high throughput of media while simultaneously receiving controls and sending monitors. To create a balanced DSP farm board, it is necessary to separate media and control functions. This can be achieved only if the DSP has a direct interface to the IP network, which will allow media to be sent over UDP/IP using RTP. This type of architecture enables aggregation using on-board layer 2 and 4 switches. Effective Usage of DSP External Memory Adding media types such as Video and enhancing the system with new features requires external memory on the DSP. This allows storage of data—such as prompts and buffering of media for streaming/recording applications—avoiding intensive host?DSP data transfer bottlenecks. To optimize external memory, the system architect must ensure that: • External memory size and width comply with current application needs and leave enough room for future expansion. • Access to external memory data is performed through a predictive caching mechanism. • A mechanism for off-line data transfer from the host to the DSP’s external memory is established. • Access to external memory should be mainly through DMA operations that work in the background, transferring blocks of data from external to internal memory and vice versa. Choosing the Right Media Processing Software Architecture Most Voice and Video media processing solutions currently available do not run on the same DSP. These types of solutions are usually expensive and their quality is questionable due to: a. synchronization issues between Voice, Video, and the transport protocol (RTP or H.223) b. delay issues If a media processing development tool based on the architecture described above is chosen, there is no flexibility to add new features and media types. Overcoming these issues requires running all media types (Voice, Video, and Data) and the transport protocols (RTP/H.223) on the same DSP. This allows run-time flexibility for the ratio between Voice and Video channels running on the DSP. The DSP software should include an “Open Framework” that is actually a pseudo operating system that can handle missions such as scheduling of DSP tasks, memory access, and “sockets.” Choosing the DSP The requirements of the DSP can be summarized as follows: • Provide external memory interface in order to have sufficient room to support new media processing tasks • Support IP interfaces directly from the DSP to enable socket-like interfaces with the network for every task • Possess adequate processor performance for execution of complicated tasks, such as multi-channel Video processing • Feature a wide range of vendors that provide software components optimized specifically for this line of DSPs
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As media processing becomes more complicated and as time-to-market is more crucial than ever in the competitive market, choosing an off-the-shelf solution that includes a comprehensive open DSP framework that runs all media types (Voice, Video, and Fax/Modem) simultaneously, will allow telecom manufacturers to focus their resources on their added value – their application. Amir Zmora is VP Marketing of Surf Communications Solutions Ltd. A longer version of this article on VoIP Gateways with illustrations as well additional resources is available at http://www.surf-com.com
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