Abstract: In one embodiment, a particular device determines a selected link from the particular device toward a root device in a computer network, wherein traffic destined away from the root device via the particular device utilizes the selected link in reverse. By monitoring a link quality of the selected link in reverse based on received traffic over the selected link, the particular device may determine whether the link quality is below a lower threshold. In response to the link quality being below the lower threshold, the particular device activates use of keepalive messages from the particular device over the selected link.

Abstract: In one embodiment, an intermediate device transmits a data message away from a root device toward a receiver device in a computer network, the data message transmitted by utilizing, in reverse, a link that had been previously selected by the receiver device toward the root device. In response to detecting that the data message did not reach the receiver device, a discovery message is may be sent to one or more neighbor devices, wherein the discovery message carries an identification (ID) of the receiver device and a discovery scope indicating how many hops the discovery message is allowed to traverse to reach the receiver device, and wherein the receiver device, upon receiving the discovery message, triggers a local link repair of the link from the receiver device toward the root device.

Abstract: In one embodiment, a computing device (e.g., border router or network management server) transmits a discovery message into a computer network, such as in response to a given trigger. In response to the discovery message, the device receives a unicast reply from each node of a plurality of nodes in the computer network, each reply having a neighbor list of a corresponding node and a selected parent node for the corresponding node. Based on the neighbor lists from the replies and a routing protocol shared by each of the plurality of nodes in the computer network, the device may create a reference topology for the computer network, and based on the selected parent nodes from the replies, may also determine a current topology of the computer network. Accordingly, the device may then compare the current topology to the reference topology to detect anomalies in the current topology.

Abstract: In one embodiment, a probing technique allows a root node to determine whether to trigger reoptimization of a computer network represented by a directed acyclic graph (DAG) without injecting unnecessary traffic into the network. The root node may store and maintain information indicative of an ideal shape or topology of the DAG. During a normal DAG maintenance operation, the root node may transmit a DAG discovery request (probe request) that is configured to probe each node within the DAG for information used to determine a current topology of the DAG. In response, each node may record the information, e.g., routing and non-routing metrics, in a DAG discovery reply (probe reply) that is propagated to the root node. Upon receiving one or more replies, the root node may analyze the metrics to determine whether the current topology of the DAG deviates from the ideal DAG topology. The root node may thus determine DAG topology deviation upon probing at minimal cost.

Abstract: In one embodiment, an intermediate device transmits a data message away from a root device toward a receiver device in a computer network, the data message transmitted by utilizing, in reverse, a link that had been previously selected by the receiver device toward the root device. In response to detecting that the data message did not reach the receiver device, a discovery message is may be sent to one or more neighbor devices, wherein the discovery message carries an identification (ID) of the receiver device and a discovery scope indicating how many hops the discovery message is allowed to traverse to reach the receiver device, and wherein the receiver device, upon receiving the discovery message, triggers a local link repair of the link from the receiver device toward the root device.

Abstract: In one embodiment, a particular device determines a selected link from the particular device toward a root device in a computer network, wherein traffic destined away from the root device via the particular device utilizes the selected link in reverse. By monitoring a link quality of the selected link in reverse based on received traffic over the selected link, the particular device may determine whether the link quality is below a lower threshold. In response to the link quality being below the lower threshold, the particular device activates use of keepalive messages from the particular device over the selected link.

Abstract: In one embodiment, a computing device (e.g., border router or network management server) transmits a discovery message into a computer network, such as in response to a given trigger. In response to the discovery message, the device receives a unicast reply from each node of a plurality of nodes in the computer network, each reply having a neighbor list of a corresponding node and a selected parent node for the corresponding node. Based on the neighbor lists from the replies and a routing protocol shared by each of the plurality of nodes in the computer network, the device may create a reference topology for the computer network, and based on the selected parent nodes from the replies, may also determine a current topology of the computer network. Accordingly, the device may then compare the current topology to the reference topology to detect anomalies in the current topology.

Abstract: In one embodiment, a root device may request that one or more devices of a computer network build a directed acyclic graph (DAG) for routing traffic within the computer network based on an objective function (OF), where the OF has one or more metrics to optimize the DAG against and optionally certain constraints. Particular devices that receive the request may then build the DAG based on the OF, and may determine and report OF feedback to the root device. Upon receiving the reports regarding OF feedback, the root device may then adjust the OF based on the feedback, and request a rebuild of the DAG from the devices based on the adjusted OF.

Abstract: In one embodiment, a distributed control technique may enable management of a monolithic routing topology of nodes in a computer network by apportioning the monolithic routing topology into a plurality of regional routing topology domains, each represented by a directed acyclic graph (DAG). The regional topology domains may include a super topology domain that is established as a super-DAG of intermediate nodes interconnected with leaf nodes and rooted by a master node of the computer network. The regional topology domains may further include at least one local topology domain that is established as a local-DAG of intermediate nodes interconnected with leaf nodes and rooted by a local root node of the computer network. Notably, a super node of the computer network may be configured to participate in both the super topology domain as an intermediate node of the super-DAG and the local topology domain as the local root node of the local-DAG.

Abstract: In one embodiment, a distributed control technique may enable management of a monolithic routing topology of nodes in a computer network by apportioning the monolithic routing topology into a plurality of regional routing topology domains, each represented by a directed acyclic graph (DAG). The regional topology domains may include a super topology domain that is established as a super-DAG of intermediate nodes interconnected with leaf nodes and rooted by a master node of the computer network. The regional topology domains may further include at least one local topology domain that is established as a local-DAG of intermediate nodes interconnected with leaf nodes and rooted by a local root node of the computer network. Notably, a super node of the computer network may be configured to participate in both the super topology domain as an intermediate node of the super-DAG and the local topology domain as the local root node of the local-DAG.

Abstract: In one embodiment, a probing technique allows a root node to determine whether to trigger reoptimization of a computer network represented by a directed acyclic graph (DAG) without injecting unnecessary traffic into the network. The root node may store and maintain information indicative of an ideal shape or topology of the DAG. During a normal DAG maintenance operation, the root node may transmit a DAG discovery request (probe request) that is configured to probe each node within the DAG for information used to determine a current topology of the DAG. In response, each node may record the information, e.g., routing and non-routing metrics, in a DAG discovery reply (probe reply) that is propagated to the root node. Upon receiving one or more replies, the root node may analyze the metrics to determine whether the current topology of the DAG deviates from the ideal DAG topology. The root node may thus determine DAG topology deviation upon probing at minimal cost.

Abstract: In one embodiment, a root device of a directed acyclic graph (DAG) may determine/detect a trigger to learn a network topology of the DAG. In response, the root device may transmit a DAG discovery request down the DAG with a route record request that requests that each device within the DAG add its device identification (ID) to a reverse route record stack for each route of a DAG discovery reply propagated up the DAG toward the root device. Upon receiving one or more DAG discovery replies, the root device may compile the recorded routes from the reverse route record stacks into a DAG network topology. Also, in one embodiment, the root device may determine “short-cuts” based on a traffic matrix generated in response to network statistics optionally included within the responses from the devices within the DAG.

Abstract: In one embodiment, a root device may request that one or more devices of a computer network build a directed acyclic graph (DAG) for routing traffic within the computer network based on an objective function (OF), where the OF has one or more metrics to optimize the DAG against and optionally certain constraints. Particular devices that receive the request may then build the DAG based on the OF, and may determine and report OF feedback to the root device. Upon receiving the reports regarding OF feedback, the root device may then adjust the OF based on the feedback, and request a rebuild of the DAG from the devices based on the adjusted OF.

Abstract: A service selection gateway (SSG) which permits multiple access quotas associated with a pre-paid service accessed by a user. For example, the user's access may be terminated if the usage exceeds a specified time or volume of data transferred (examples of access quotas). According to another aspect, access of a service is permitted based on different tariffs. Thus, a user may be charged differently depending on the applicable tariff. In an embodiment implemented in the context of pre-paid tariffs, multiple access quotas may be received associated with the same resource, and each quota may be computed according to a corresponding tariff.

Abstract: In one embodiment, a method of a kernel dumper module includes generating a dump file associated with a kernel when the kernel crashes, storing the dump file to a functional memory upon applying an overwrite protection to a core dump of the dump file, restarting the kernel through a warm reboot of the kernel such that the core dump is not erased from the functional memory, and transferring the core dump to a system file using the kernel.

Abstract: Methods and systems have been provided that allow a user to access a file in a computational device. The location of the file is made transparent to the user. The request for the file includes the filename. The filename is mapped to the location of the file in the computational device. The file is returned if it is present in the cache of the computational device. Otherwise, the file is retrieved from a storage device. The cached files are, deleted from the cache on the basis of a policy-based-cache-deletion mechanism.

Abstract: A method is disclosed for authorizing a prepaid network service in a data network. A network end station issues a request for a prepaid network service. At a network node, such as a router serving as a gateway for selecting services, a determination is made about whether a user associated with the end station is authorized to access the prepaid network service. Network traffic from the end station is forwarded to a service provider only when the user is authorized to use the prepaid network service. Specific embodiments provide message flows among a mobile station, gateway support node, router, and authentication server that support providing prepaid services in a packet-switched network for mobile communication. In certain embodiments, a connection is held open for an end station while a prepaid quota value is refreshed at a portal, thereby reducing overhead and precluding the need to repeat user logon steps.

Abstract: Methods and apparatus are disclosed for performing layer 2 authentication of a Mobile Node supporting Mobile IP in an SSG based network. Layer 2 information including at least one of a MAC address and username associated with the Mobile Node is obtained. An orphaned host object including the layer 2 information (e.g., MAC address) is then generated. The orphaned host object is then unorphaned when an IP address associated with the layer 2 information (e.g., MAC address) is received such that the unorphaned host object includes the IP address and the layer 2 information.

Abstract: In one embodiment, a method of a kernel dumper module includes generating a dump file associated with a kernel when the kernel crashes, storing the dump file to a functional memory upon applying an overwrite protection to a core dump of the dump file, restarting the kernel through a warm reboot of the kernel such that the core dump is not erased from the functional memory, and transferring the core dump to a system file using the kernel.

Abstract: A service selection gateway (SSG) which receives data indicating tariff switching points, and sends accounting records enabling accurate computation of traffic volumes in each switching duration is described. In one embodiment, a counter value indicating the traffic volume for each tariff duration is sent. In an alternative embodiment, at least one accounting record containing two counters is sent in each duration, with one counter indicating an aggregate count of traffic volume (e.g., since the subscriber started a session) and another counter containing a marginal (or incremental) value since a switching point. Such an accounting record can be sent at any time point in a tariff duration, and the traffic volume in each tariff duration can be computed accurately.