Descriptor of the preferred route (all hops specified). Descriptor gives information about the domain, nodename, slot, and possibly a port for each hop in the route. For example, Node1 15 terrestrial link between Node1 slot 15 and Node2 slot 15. While doing a SET operation the following general format for specifying a preferred route should be used: (<node-name>.<TRK>[.0])* - <node-name> (<node-name>.<slot.port>)* - <node-name> Some more valid descriptions are: 1) Node1.15.1 - Node2.13.1 - Node3 2) Node1.15.1-Node2.13.1-Node3 3) Node1.15 - Node2.12 - Node3.15 - Node4 4) Node1.15.0 - Node2.12.0 - Node3.15.0 - Node4 NOTE: a> (...)* notation means the description inside parenthesis may repeat any number of times, only limited by the total length which is 255 and the [...] notation signifies that it is optional. b> 1) & 2) are equivalent so are 3) & 4). c> Even GET preferred route description will be made consistent with that of SET operation in the future releases. d> An empty string (null or string of blank spaces) will clear the pref route description equivalent to delete pref route.