Thomas Kernen

Analysis of lock times of PTP slave under varying network load conditions using class based queuing

Clock synchronization for professional video broadcasting imposes new requirements on the Precision Time Protocol which have not received much attention until now: Extremely short lock times of PTP slave nodes. This paper presents techniques for fast locking together with extensive measurements of lock time behavior in congested networks using different types and generations of network elements. Additionally, possible impacts of the hybrid PTP mode on offsets caused by asymmetry due to non PTP-aware network devices are analyzed.

Optimised IP Multicast Architectures for Real-Time Digital Workflows

Across the entire broadcast chain from production to distribution, real-time digital workflows are now commonly being distributed over Internet Protocol (IP) networks. Many deployments are leveraging IP multicast to optimise the delivery from a source to a set of diverse end points (receiver) such as video servers, mixers, quality control units, video monitoring, time & synchronisation slaves, etc. These devices require reliable and deterministic network behaviour to ensure an optimal operating environment. Technology developments in multicast-related protocols and architectures such as Source Specific Multicast, transport virtualisation, Fast Convergence, inline video monitoring metrics, combined with multicast hardware replication improvements in routers and switches, have significantly increased the reliability of the network layer transport for digital workflows. By preventing bandwidth duplication or centralised congestion points, reducing outage duration by using dual paths between source and receivers, combined with protocol, hardware, monitoring and security improvements, the overall reliability of IP multicast networks has dramatically increased in the last decade.