1. A system comprising: a plurality of host machines for hosting a plurality of virtual machines, each host machine comprising: a managed physical switching element (MPSE) comprising a plurality of ports for performing link layer forwarding of packets to and from a set of virtual machines running on the host machine, each port associated with a unique media access control (MAC) address; and a managed physical routing element (MPRE) for receiving a data packet from a port of the MPSE and performing network layer routing in order to forward the received data packet from a first virtual machine of a first network segment to a second virtual machine of a second network segment, wherein the MPRE comprises a plurality of logical interfaces, each logical interface for receiving data packets from a different segment of the logical network; and a physical network for interconnecting the plurality of host machines, wherein each of the logical interfaces on the MPREs of the plurality of host machines is addressable by an identical link layer address, and wherein, for each MPRE of each host machine, each logical interface for receiving data packets from the first network segment of the logical network has a same network layer address that is different from a network layer address used by each logical interface for receiving data packets from the second network segment of the logical network.