  Service providers employ different transport technologies like PDH,
SDH/SONET, OTN, DWDM, Ethernet, MPLS-TP etc. to support different types of
traffic and service requirements. Dynamic service provisioning requires the use
of on-line algorithms that automatically compute the path to be taken to
satisfy the given service request. A typical transport network element supports
adaptation of multiple technologies and multiple layers of those technologies
to carry the input traffic. Further, transport networks are deployed such that
they follow different topologies like linear, ring, mesh, protected linear,
dual homing etc. in different layers. Path computation for service requests
considering the above factors is the focus of this work, where a new mechanism
for building an auxiliary graph which models each layer as a node within each
network element and creates adaptation edges between them and also supports
creation of special edges to represent different types of topologies is
proposed. Logical links that represent multiplexing or adaptation are also
created in the auxiliary graph. Initial weight assignment scheme for
non-adaptation edges that consider both link distance and link capacity is
proposed and three dynamic weight assignment functions that consider the
current utilization of the links are proposed. Path computation algorithms
considering adaptation and topologies are proposed over the auxiliary graph
structure. The performance of the algorithms is evaluated and it is found that
the weighted number of requests accepted is higher and the weighted capacity
provisioned is lesser for one of the dynamic weight function and certain
combination of values proposed as part of the weight assignment.
