Ciena Corporation Infinera Corporation Individual Apstra Equinix Inc Cisco Systems This document illustrates a way to integrate a new class of nodes and links in segment routing to represent transport/optical networks in an opaque way into the segment routing domain. An instance of this class would be optical networks that are typically transport centric by having very few devices with the capability to process packets. In the IP centric network, this will help in defining a common control protocol for packet optical integration that will include optical paths as 'transport segments' or sub-paths as an augmentation to packet paths. The transport segment option also defines a general mechanism to allow for future extensibility of segment routing into non-packet domains.