A system for interconnecting a plurality of separate networks, the system comprising: a plurality of network segments located at different segmented networks (3505, 3510, 3515), the plurality of network segments comprising at least (i) a first network segment of a first network segmented using a first technique and (ii) a second network segment of a second network segmented using a second technique; a set of interconnection forwarding elements (3605, 3610, 3615); characterized in that: each interconnection forwarding element (3605, 3610, 3615) has a first physical port that interfaces with a particular one of the network segments and a second physical port that interfaces with an interconnecting network to which all of the interconnection forwarding elements (3605, 3610, 3615) connect to provide connections between the plurality of network segments; and a network controller is configured to manage the set of interconnection forwarding elements (3605, 3610, 3615) by defining a logical forwarding element (3700, 4000) that connects the plurality of network segments located at different segmented networks (3505, 3510, 3515), the logical forwarding element (3700, 4000) comprising logical ports to which each of the network segments couple, wherein the logical forwarding element (3700, 4000) is for implementation by each of the interconnection forwarding elements (3605, 3610, 3615), with each logical port corresponding to one of the interconnection forwarding elements (3605, 3610, 3615). a plurality of network segments located at different segmented networks (3505, 3510, 3515), the plurality of network segments comprising at least (i) a first network segment of a first network segmented using a first technique and (ii) a second network segment of a second network segmented using a second technique; a set of interconnection forwarding elements (3605, 3610, 3615); characterized in that: each interconnection forwarding element (3605, 3610, 3615) has a first physical port that interfaces with a particular one of the network segments and a second physical port that interfaces with an interconnecting network to which all of the interconnection forwarding elements (3605, 3610, 3615) connect to provide connections between the plurality of network segments; and a network controller is configured to manage the set of interconnection forwarding elements (3605, 3610, 3615) by defining a logical forwarding element (3700, 4000) that connects the plurality of network segments located at different segmented networks (3505, 3510, 3515), the logical forwarding element (3700, 4000) comprising logical ports to which each of the network segments couple, wherein the logical forwarding element (3700, 4000) is for implementation by each of the interconnection forwarding elements (3605, 3610, 3615), with each logical port corresponding to one of the interconnection forwarding elements (3605, 3610, 3615). each interconnection forwarding element (3605, 3610, 3615) has a first physical port that interfaces with a particular one of the network segments and a second physical port that interfaces with an interconnecting network to which all of the interconnection forwarding elements (3605, 3610, 3615) connect to provide connections between the plurality of network segments; and a network controller is configured to manage the set of interconnection forwarding elements (3605, 3610, 3615) by defining a logical forwarding element (3700, 4000) that connects the plurality of network segments located at different segmented networks (3505, 3510, 3515), the logical forwarding element (3700, 4000) comprising logical ports to which each of the network segments couple, wherein the logical forwarding element (3700, 4000) is for implementation by each of the interconnection forwarding elements (3605, 3610, 3615), with each logical port corresponding to one of the interconnection forwarding elements (3605, 3610, 3615).