Reliable IP Video Transport
In recent years IP networks have proven to be capable of delivering flawless, high quality video thanks to increased bandwidth combined with MPLS technologies and QoS mechanisms such as service prioritization. Robustness and usability have been further enhanced with technology such as Forward Error Correction (FEC), ARQ, advanced monitoring, intelligent switching and enhanced video network management. By utilising IP in contribution and distribution networks, broadcasters and operators can take advantage of the greater flexibility and lower connectivity costs provided by IP. Service providers, operators and broadcasters now have the tools to monitor, correct, conceal, backup and seamless switch to the best video signal and thereby deliver flawless high quality content over video centric IP networks.
Monitoring IP video signals is an integral part of Techex's product offering, providing statistics on IP packet loss, reordered and duplicated packets, data recovered by Forward Error Correction as well as latency and delay variation. Long-term trends are displayed in a user-freindly web interface, providing valuable information for IP network diagnostics. The video payload of IP streams are, of course, also monitored, and MPEG-2 Transport Streams are monitored according to the standard alarm conditions as defined by the ETSI TR 101 290 specification. To enable performance monitoring, statistics are provided via SNMP and XML monitoring interface so that service providers or broadcasters can integrate the information into 3rd party network management systems.
For service providers that offer premium services with premium availability, T-VIPS has implemented a set of features designed to greatly enhance the reliability of video transport over IP. Although IP networks today are very robust, impairments such as delay variation (jitter) and occasional packet loss can occur and must be taken care of by video end-points to ensure error-free video transport. While IP jitter can be compensated for by buffering and regulation mechanisms, IP packet losses can be corrected using Forward Error Correction (FEC). With FEC, a small number of redundant FEC packets are sent together with the video packets for protection. These FEC packets can be used to regenerate any lost video packets. The amount of FEC protection and resulting overhead can be adjusted, as necessary, to fit the characteristics of the IP link. As an example, IP microwave links will typically require a higher level of FEC protection than IP fibre links.
In order to achieve high availability, service providers need to consider that the most severe service outages happen due to complete network link failures (e.g., accidental fibre cable cutting). Providing network link redundancy is critical for success when offering managed video services. Consider a scenario in which video is transported across both primary and secondary network links simultaneously; T-VIPS has developed solutions for perfectly seamless switching from primary to secondary video stream in the case of link failure. With a seamless switching solutions from T-VIPS this is no negative impact on the signal that is delivered to the customer on the receive side, and subsequently no impact on the end-viewer’s Quality of Experience (QoE). Such solutions have been developed for both the JPEG2000 Gateways as well as ASI/TS over IP Gateways, together with architectures that also take redundancy in video end-points into consideration.