Cisco Technology, Inc.

Cisco Systems Inc.

James R Forster

Feisal Y Daruwalla

Guenter E Roeck

Joanna Qun Zang

Michael R Thomas

Richard Woundy

Yong Lu

Mark W Litwack

John T Chapman

Mark E Millet

John K Chen

Joseph O'Donnell

Bruce A Cole

A protection CMTS is available to immediately service a cable modem should that modem's service from a working CMTS fail for any reason. To speed the service transfer (cutover) from the working CMTS to the protection CMTS, the cable modem may preregister with the protection CMTS well before the cutover becomes necessary. The cable modem's registration with both the working CMTS and the protection CMTS preferably employs a single IP address, so that the cable modem need not obtain a new IP address during cutover. While the cable modem may register with both the working CMTS and the protection CMTS, the devices are designed or configured so that only the working CMTS injects a host route for the cable modem into the appropriate routing protocol. Only after cutover to the protection CMTS does the protection CMTS inject its host route.

Method for a cable modem to rapidly switch to a backup CMTS

A technique is provided for managing VPN packet flows over shared access data networks. Each node in the shared access network typically has an identifier or ID associated with it which is used at a Head End of the shared access network to uniquely identify that particular node from the other nodes in the network. According to the technique of the present invention, the node ID may be used at the Head End of the network to identify not only the corresponding node, but also to identify any virtual private networks (VPNs) of which the corresponding node is a member. Using the technique of the present invention, nodes which are members of the same VPN within a shared access network may exchange packets in a manner which does not require the packets to be routed outside the shared access network.

Technique and apparatus for using node ID as virtual private network (VPN) identifiers

Routing protocol based redundancy design for shared-access networks

A CMTS redundancy technique requires at least two CMTS interfaces (e.g., line cards) on one or more CMTS chassis at the head end of a cable network. One of the CMTSs serves as a backup or 'protecting' CMTS. When another CMTS (a 'working' CMTS) becomes unavailable to service its group of cable modems, the protecting CMTS takes over service to those cable modems. The SWITCHOVER takes place transparently (or nearly transparently) to the cable modems. The protecting CMTS provides service on the same downstream channel as used by the working CMTS. The cable modems need not modify any settings pursuant to their cable modem communication protocol (e.g., DOCSIS ranging). This transparency to the cable modems is realized by keeping the working and protecting CMTSs in synchronization regarding service parameters for the cable modems. In other words, the protecting CMTS maintains a list of current parameters for allowing service to the cable modems.

Cable network redundancy architecture

An IP address is automatically discovered by a network endpoint, such as a PC or router. The endpoint listens for a broadcast network packet or promiscuously listens for a unicast network packet sent from a web browser from a host system. The network packet includes the IP address for the host system and a preselected IP domain name. The IP domain name is used to initiate the address discovery in the endpoint. The IP address from the host system is used by the endpoint as a seed for generating a proposed IP network address. The endpoint then uses an address resolution protocol (ARP) to determine whether the proposed IP address is currently assigned to any other device in the network. If no device in the network responds to the ARP request, the proposed IP address constitutes a unique address on a network segment. Because the proposed address is not used by any other device in the subnetwork, it is self-assigned to the endpoint.

Method and apparatus for serverless internet protocol address discovery

Growing community of inventors

Los Altos, CA, United States of America

James R Forster