19.3 Light Trail Characteristics

There is no need to dynamically configure any switches when using light trails to carry IP bursts. This leads to an excellent provisioning time. Moreover, the major advantage of using light trails for burst traffic, as compared to optical burst switching (OBS), is the improved wavelength utilization. Here utilization is defined as the ratio of the capacity used over time for actual data transmission to the total reserved capacity. It has been shown that the utilization in OBS is severely degraded compared to that in light trails as the network load increases [168]. More specifically, the utilization of light trails is an order of magnitude better than that in OBS under similar conditions.

Multicasting in the optical layer is another salient feature of the light trail architecture. Nodes in a light trail are able to send the same quanta of information to a set of downstream nodes without the need for special processing or control arbitration.

In general, a light trail offers a technologically exclusive solution that enables a number of salient features and is practical. It exhibits a set of properties that distinguishes and differentiates it from other platforms. The following four characteristics are key properties.

• The light trail provides a way to groom traffic from many nodes to share a wavelength path to transmit their subwavelength capacity traffic.

• The light trail is built using mature components that are configured in such a way as to allow extremely fast provisioning of...