1. A computer-implemented method for expediting content delivery in a peer-to-peer (P2P) overlay network, comprising: caching a plurality of segments associated with multi-media content in a local cache on a local cache and directory server within a local P2P network which includes a requesting peer node that requests a respective segment associated with the multi-media content; maintaining, at the local cache and directory server, a mapping between the multi-media content and another local peer node that transiently stages the segments associated with the multi-media content; receiving, at the local cache and directory server, a packet forwarded from a gateway router within the local P2P network, wherein the packet includes a request originated from the requesting peer node and identifies a segment associated with the multi-media content, and wherein the request is forwarded to the local cache and directory server in place of a central directory server within another local P2P network from the gateway router responsive to determining that the request is a P2P request based on packet attributes which comprise of a destination address, a destination port type, and a destination port number of the packet; and responsive to the multi-media content mapped to the other local peer node, sending an address of the other local peer node to the requesting peer node; responsive to the multi-media content not mapped to the other local peer node, forwarding, from the local cache and directory server, the request to the central directory server.