A novel method that uses the source port field in the transport or connection layer (L4) header to encode control plane information is provided. Specifically, the method encodes control plane information in UDP or TCP source port field of data plane tunnels in an overlay network such as VXLAN. Network virtualization is implemented by a network controller over an overlay network on the physical fabric. The network controller provides a mapping table to the data plane hosts for mapping the encoded bits in the source port field to semantically richer information. The data plane hosts in turn uses the encoded source bits and the mapping table to infer this semantically richer information. This semantically richer information is used to allow receivers of proxied traffic to learn the address of the original sender. The semantically richer information can also be used to enable ECMP for the transmitted packets.