Cisco Technology, Inc.

Bernard Ernst Volz

Kenneth Kinnear, Jr

Mickael James Graham

Madhu Sudan

Hemant Singh

Mark Stapp

William Beebee

Chad Mikkelson

Jeffrey Riddel

Jeffrey Cioli

Neil Russell

Michael Reekie

Lon-Leighton Barrett

Sri Hary Vengadasubbu

A method for providing services by a pair of servers to clients through one or more relay agents. The pair includes a second server configured to respond to discovery messages, and a first server configured to be unresponsive to the discovery messages. The method includes: at the first server, receiving a first discovery message from a first relay agent at a first time; and configuring the first server to become responsive to the first discovery message when a number of discovery messages from the first relay agent is equal to or greater than a predetermined number threshold and when a time lapse between the first time and a second time is equal to or greater than a predetermined time threshold. The count and time period are reset if the second server is determined to be responsive to discovery messages by monitoring the client request messages.

Handling network failures in networks with redundant servers

In one embodiment, methods are described for recovering lost customer premises equipment (CPE) information on a cable modem termination system (CMTS) in the presence of only Dynamic Host Control Protocol Version 6 (DHCPv6) CONFIRM. A CMTS purges routing information for an Internet Protocol Version 6 (IPv6) node, such as a CPE router, in response to detecting an interface reset for the IPv6 node. IPv6 addresses and prefixes information for the IPv6 node is gleaned from a DHCPv6 CONFIRM message received from the IPv6 node. By sending portions of the IPv6 addresses and prefixes information within a DHCPv6 LEASEQUERY message, a DHCPv6 CONFIRM message with an embedded DHCPv6 LEASEQUERY message, or a DHCPv6 CONFIRM message with an Interface-ID option, a reply message can be received that contains the purged routing information for the IPv6 node.

Recovering lost device information in cable networks

In an embodiment, a data processing apparatus comprising one or more electronic digital processors; Dynamic Host Configuration Protocol (DHCP) server logic coupled to the one or more processors; an active leasequery channel response logic coupled to the DHCP server logic which when executed causes the one or more processors to perform receiving, from a particular DHCP client among a plurality of DHCP clients, an active leasequery initiation message requesting the DHCP server logic to actively send update messages about changes in network address leases that the DHCP server logic manages; wherein the active leasequery initiation message comprises a channel identifier value; determining whether the channel identifier value matches a client class that the DHCP server logic manages; in response to determining that the channel identifier value does match a client class identifier that the DHCP server logic manages, sending, to the particular DHCP client, one or more DHCP response messages describing any changes in network address leases that the DHCP server logic performs only for a subset of the DHCP clients that are in the matched client class.

Actively updating clients with selected data

A technique is performed in a first device of a set of devices. The technique involves receiving a query message from a network node, the query message requesting data regarding a network resource. The technique further involves accessing an identifier which indicates whether the first device is in charge of the network resource, and providing a response message to the network node in response to the query message. The response message is provided after waiting a predefined amount of time when the identifier indicates that the first device is not in charge of the network resource and there is reason to believe another device of the set is operating. The response message is provided without waiting the predefined amount of time when the identifier indicates that the first device is in charge of the network resource. Moreover in some situations, the first device may choose to not respond.

Responding to a DHCPLEASEQUERY message

As a server device receives packets from a client device, the server device counts the number of packets received over a particular time interval and compares the result with a preset packet transmission threshold. When the number of packets received from the client device in the time period reaches or exceeds the packet threshold, the server device can detect a potential malfunction of the client device and as such, refrains from processing further packets from the client device. By rate limiting based upon the number of packets received from the client device over a given time interval, rather than on the bandwidth taken by the requests received from the client device, the server device can minimize monopolization of the server device's resources as caused by the packets received at a relatively low rate from a client device.

Method and apparatus for rate limiting client requests

In an embodiment, an apparatus comprises one or more processors; logic coupled to the one or more processors for execution and configured to perform receiving, from a second computer, a request for information about a first address of a customer premises equipment (CPE) device and including a second address of the second computer; determining that an address record of the first address identifies a third address, which is different from the second address, for a termination unit associated with the CPE device; in response to the determining: causing the generating and sending of one or more updates of inter-domain routing protocol information for the CPE device; updating the address record by storing the second address in a location that identifies the termination unit that is associated with the CPE device.

Dynamically transitioning static network addresses

A technique is performed within a DNS server to respond to a DNS message. The technique includes receiving the DNS message from a requesting device (e.g., a DHCP server), and generating a search result based on a search of a portion of the DNS message for a request to delete a specific record (i.e., a specific, predefined record which is not expected to exist in the DNS). The technique further includes selectively providing and not providing current state information (or other information) to the requesting device depending on whether the search result indicates that the request to delete the specific record resides within the portion of the DNS message. Such operation allows for augmented operation with augmented DNS clients, as well as non-augmented operation with legacy equipment.

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Center Harbor, NH, United States of America

Bernard Ernst Volz