Cisco Technology, Inc.

Timothy Patrick Donahue

Ralph Droms

David Delano Ward

Donald Edward Banks

Denis Leclerc

William Mark Townsley

Gary S Muntz

Doron Oz

John C Carney

Guy Fedorkow

Michael E Lipman

Balachander Chandrasekaran

Thomas W Uban

Vijay J Savla

Michael E Wildt

Guy C Fedorkow

Techniques are provided for performing dynamic DNS-SD. In an embodiment, an apparatus includes one or more databases, one or more transceivers to receive a first Domain Name System (DNS) query from a first computing device, the first DNS query defining a first service discovery name space, and one or more processors in communication with each of the one or more databases and the one or more transceivers. The one or more processors generate and append a first metadata associated with the first computing device to the first DNS query. The one or more transceivers transmit the first DNS query and the first metadata to a Domain Name System (DNS) server computer, receive, from the DNS server computer, a first response responsive to the first DNS query, and relay, to the first computing device, the first response.

Dynamic DNS-based service discovery

Techniques are provided for performing domain name system (DNS) service discovery based on policy evaluations. In an embodiment, policy data is represented as DNS-SD records and is used to control visibility of services for service requesting devices. The policy data may describe policies for a particular type of a service or a particular service delivery unit. The visibility of service delivery units is determined through evaluations of the policies in policy data. In some embodiments, additional metadata may be retrieved to be used in the policy evaluations. In certain embodiments, based on the policy evaluations service data about only a subset of service delivery units available is returned to a service requesting device in response to a DNS-SD query.

Visibility control for domain name system service discovery

A service is applied in a packet switching device to both directions of a flow of packets through the packet switching device, with the application of this Layer-4 to layer-7 service to one direction requiring state information shared from the application of the service to packets traversing in the other direction. The service (e.g. firewall, network address translation) can be applied by different processing complexes which do not share memory; thus, state information is communicated between the processing complexes. When the service is applied by a single processing complex, packets can be directed explicitly to the single processing complex. The inline application of services in a packet switching system typically eliminates the need to change a packet's path through the packet switching system to that through a dedicated application server, and may eliminate the need for a dedicated services card or blade server.

Application of services in a packet switching device

Methods, apparatus, computer-storage media, mechanisms, and means associated therewith are used to limit network device resources based on the identification of the Internet Protocol version 6 (IPv6) originating entity (e.g., subscriber of a network carrier). As an IPv6 originating entity will typically be assigned 2or more valid IPv6 addresses, the originating entity may send packets with a source address of any of these valid IPv6 addresses and still be compliant with Internet standards and/or other specifications (e.g., RFCs). By determining the originating entity and controlling the allocation of network device resources based on the originating entity (in contrast to on a per valid IPv6 address basis), a network service provider can manage its network device resources, such as in a manner to prevent a depletion of resources caused by an originating entity using a plethora valid IPv6 addresses, or a malicious denial-of-service attack.

Limiting of network device resources responsive to IPv6 originating entity identification

A system and method for supporting a 'hitless' switchover from an Active to a Standby processor uses a hybrid synchronization of interface states to allow applications that have been modified to have HA aware features and non-modified applications to function on the system. An interface description data block on the Standby RP is synchronized to the interface description data block on the Active RP and is maintained in a shadow state when the Active RP controls the system. In the event of a switchover between the RPs the interface description data block on the Standby RP is copied from the shadow state to a real state and applications on the Standby RP are notified of a status change.

Hybrid interface synchronization method and driver-client model for high availability systems

A method is disclosed for providing interoperation of a first execution image of a first version and a second execution image of a second version. A compatibility matrix specifies whether the versions are compatible, base-level compatible, or incompatible. In one embodiment, the compatibility matrix may comprise a sparse table that stores a compatibility indicator for all permutations of a plurality of versions of a network operating system. As part of initialization of a system that includes the first execution image and second execution image, version information for the execution images is determined. An entry in the compatibility matrix corresponding to the versions is identified. The execution images are operated in a fully synchronized state when the identified entry of the compatibility matrix specifies that the versions are either compatible or base-level compatible. Individual components of the execution images interoperate according to the results of individual session negotiations. If the versions are incompatible, an alternative redundancy operation mode may be used. Embodiments provide for negotiation of compatible message versions and capabilities among peer components or clients of the execution images as source information to generate the compatibility matrix.

Method and apparatus providing interoperation of execution images of different versions

In one embodiment, an intermediate node includes one or more active forwarding planes and one or more redundant forwarding planes. The intermediate node may also include one or more active control planes and one or more redundant control planes. A test packet is generated, in some cases by a redundant control plane, and transferred to a redundant forwarding plane. The operational state of the redundant forwarding plane is verified, at least in part, by using operational software and hardware contained in the redundant forwarding plane to forward the test packet from the redundant forwarding plane to a target line card. The target line card loops the test packet back to the redundant forwarding plane as part of the verification process. In some cases, the redundant control plane processes the looped-back test packet.

Growing community of inventors

Natick, MA, United States of America

Timothy Patrick Donahue