Introduction

Next Generation Base stations (Node-Bs) are equipped with Ethernet interfaces for efficient transport of data traffic. However, voice and timing information still need to be transported reliably over these backhaul links. Chronos’ SyncWatch product together with Calnex’s Paragon can be used to fully stress and verify the integrity of synchronisation transported over Ethernet/IP networks.

As Next Generation Networks (NGNs) evolve, certain applications will become more susceptible to variable latency experienced by packet network traffic. This variable latency Packet Delay Variation (PDV) is now able to be measured and modelled using Calnex’s innovative Paragon platform.

The Paragon In-line Impairment equipment can capture a network PDV signature and then reproduce it in the carrier’s test bed for type approval and immunity testing of network elements to assess network timing performance degradation under different impairment scenarios.

In a lab test environment, traditional network elements which have E1/T1 interface will receive their timing from a suitable primary reference source and use Calnex’s Paragon platform to stress the packet network via the appropriate interworking function (IWF).

After the IWF, the Chronos SyncWatch probe detects the Time Interval Error (TIE) of the E1/T1 signal and evaluates the bit rate timing stability using the Maximum Time Interval Error (MTIE) metric as defined in the ITU standards.

The Calnex PDV In-line Impairment generator combined with the Chronos SyncWatch probe ensures that packet delay and bit rate timing errors may be simultaneously monitored and correlated to packet delay variation signatures in order to enable applications and network equipment to be fully evaluated so that they may be deployed in existing networks as they migrate to NGN architecture.

For the first time mobile and fixed line operators can identify the link between packet delay and time errors in the bit stream thus enabling them to fully type approve existing equipment in their networks when connected to an IP based transmission path.

The products offered by Chronos and Calnex complement one another and provide the complete solution required to stress-test and measure the transport services to PDV variations. For the first time, the combined solutions offer design and evaluation teams the ability to test with real-world PDV patterns in a controlled and repeatable environment, and produce quantitative results that can be used to assess vendor equipment’s readiness for deployment.

As an operator begins to deploy CES/Pseudowire services, so SyncWatch can be deployed to assure initial services perform as expected under real operating conditions. To improve quality of service, operators have already taken the decision to install many SyncWatch probes in the Circuit Switched networks to monitor synchronisation delivery. The same SyncWatch technology delivers even bigger benefits in NGNs. In addition, the SyncWatch system can forward SNMP traps northbound to umbrella management systems ensuring full visibility of any timing problems.

Whether 1588-2008, ACR or SyncE is used to provide timing for the Pseudowire service, these tools provide the data necessary to make good engineering and business decisions.

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