A system comprising: a network analyzer, a network controller and network metric monitors, wherein the plurality of network metric monitors are configured to: obtain measurements for one or more network metrics, and transmit network assessment information based on the obtained measurements to the network analyzer in a first network, the network assessment information indicating values for characteristics of one or more network paths from the respective network metric monitor to a node in a second network, wherein at least one of the plurality of network metric monitors is situated in a network external to the first network, and wherein at least one network metric monitor is situated in a network node and is configured to obtain measurements based on at least one data flow using a connection-oriented transport-layer protocol and traversing through, or originating at, the network node; the network analyzer is configured to: receive the network assessment information from the plurality of network metric monitors, and aggregate the received network assessment information; and the network controller for the first network is configured to: select, based on the aggregated information, a route from among a plurality of potential routes from the first network to the node in the second network that satisfies a set of criteria, and set routing policy for data flows from the first network through the node in the second network using the selected route. a network analyzer, a network controller and network metric monitors, wherein the plurality of network metric monitors are configured to: obtain measurements for one or more network metrics, and transmit network assessment information based on the obtained measurements to the network analyzer in a first network, the network assessment information indicating values for characteristics of one or more network paths from the respective network metric monitor to a node in a second network, wherein at least one of the plurality of network metric monitors is situated in a network external to the first network, and wherein at least one network metric monitor is situated in a network node and is configured to obtain measurements based on at least one data flow using a connection-oriented transport-layer protocol and traversing through, or originating at, the network node; obtain measurements for one or more network metrics, and transmit network assessment information based on the obtained measurements to the network analyzer in a first network, the network assessment information indicating values for characteristics of one or more network paths from the respective network metric monitor to a node in a second network, wherein at least one of the plurality of network metric monitors is situated in a network external to the first network, and wherein at least one network metric monitor is situated in a network node and is configured to obtain measurements based on at least one data flow using a connection-oriented transport-layer protocol and traversing through, or originating at, the network node; the network analyzer is configured to: receive the network assessment information from the plurality of network metric monitors, and aggregate the received network assessment information; receive the network assessment information from the plurality of network metric monitors, and aggregate the received network assessment information; and the network controller for the first network is configured to: select, based on the aggregated information, a route from among a plurality of potential routes from the first network to the node in the second network that satisfies a set of criteria, and set routing policy for data flows from the first network through the node in the second network using the selected route. select, based on the aggregated information, a route from among a plurality of potential routes from the first network to the node in the second network that satisfies a set of criteria, and set routing policy for data flows from the first network through the node in the second network using the selected route.