A recent incident on our network underlines the potential for improved reliability with the new generations of DWDM equipment. During some planned maintenance, a network engineer from another telecoms operator disturbed one of Vtesse’s fibres at a data centre. We shall never know exactly what happened but probably a tight kink was put into a fibre cable. Something like this can turn into a major incident as we have dozens of 10Gbps services to the particular location and even a small kink can cause dB loss which in turn can cause service degradation across multiple customers and services. In this particular case a serious loss of 20dB suddenly appeared on the route.
Our Network Operations Centre (NOC) immediately experienced alarms on a range of services. On conventional DWDM networks addressing the incident would involve a qualified engineer logging into DWDM equipment and manually adjusting the power balancing to ensure that the additional dB loss was compensated for until the cause could be investigated in the field. This can take a significant amount of time to implement and the action in itself potentially carries risks as diagnostic errors by the engineer could make matters worse.
With Vtesse’s new Tellabs ROADM network, there is automatic power balancing on the network. As soon as the network detected the 20dB loss, the equipment automatically adjusted the power on the route and within 2 seconds the route was operating normally again with no manual intervention by the NOC. Service degradation was kept to an absolute minimum (most customers wouldn’t have noticed) and any risk of exacerbating the problem was kept to a minimum as no human intervention was required.
What can we conclude from this? Well we would say not all optical networks are the same and when choosing a network operator, it’s worth understanding what generation of DWDM equipment is being used, particularly if reliability is a key criteria for supplier selection.