Cisco Technology, Inc.

John J Jannotti

James W O'Toole, Jr

James O'Toole

M Frans Kaashoek

The invention is directed to techniques for maintaining a map of node relationships for a network of nodes (e.g., network of computers). In one example, the map of node relationships represents relationships overlaying and typically different from the network of physical connections among the nodes. Each child node periodically checks in with its parent nodes, and the parent nodes can thus determine when a child node has terminated a relationship with the parent or created a new relationship with a new parent. Changes in relationships propagate upward through the network of nodes so that each node maintains a map of the relationships among the descendants of that node. A root node receives the propagated change relationship information and maintains a map of the entire network and valid pathways through the network. The root node can use the map when responding to a request from a client to receive services from a node in the network and redirects the client to attach to a node in the network that has a valid path to the root node. The root node can then broadcast data (e.g. a stream of video data) throughout the network, which is received by all the clients attached to nodes in the network.

Methods and apparatus for maintaining a map of node relationships for a network

The present invention may be used for determining a topology of a network in the presence of network address translation. From an active client behind a translating device, communications are initiated that effect the network address translation. The communications are monitored beyond the translating device to infer partitioning of servers into equivalence sets relative to the network topology induced by the network address translation. Active clients behind the translating device may include a respective actual sending address in a message sent to a server beyond the translating device. The server beyond the translating device distinguishes between communications affected by and not affected by network address translation, which may include comparing an apparent source address of a message against an actual address provided in the message by the active client behind the translation device. The external server may also distinguish between active and passive client messages. The server server may cause a message to a passive client to be redirected to an active client; the active client, in turn, communicates to the external server. The external server stores addresses of devices in translated address sets, which may be maintained in a database and managed in a database manager.

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Cambridge, MA, United States of America

John J Jannotti