Cisco Technology, Inc.

Nan Yi

Huimin She

Chuanwei Li

Wenjia Wu

Hui Li

Li Zhao

Lele Zhang

Haibo Dong

Ling Wei

In one embodiment, a method comprises: determining, by a network device that is configured for joining a local directed acyclic graph (DAG) instance in a data network, an unreachability by the network device to any member of the local DAG instance; generating and broadcasting, by the network device, a request message that identifies the network device requesting to join the local DAG instance, the request message causing a neighboring network device in a global DAG instance of the data network to rebroadcast the request message for reception by a member of the local DAG instance, the neighboring network device a non-member of the local DAG instance; and receiving, by the network device, a reply message indicating a member of the local DAG instance is reachable via the neighboring network device in the global DAG instance.

Interconnecting local RPL instance nodes via global RPL instance node as AODV relay

In one embodiment, a method comprises determining, by a network device in a wireless data network, that a prescribed Clear Channel Assessment (CCA) threshold is unsuitable for use on an identified wireless network channel among available wireless network channels, based on a determined variance of a corresponding channel transmit attempt failure rate for the identified wireless network channel, relative to an expected variance in channel transmit attempt failure rates that is determined across the respective available wireless network channels; and selectively adjusting the corresponding CCA threshold for the identified wireless network channel, until a second determined variance of the corresponding channel transmit attempt failure rate, at the identified wireless network channel, falls below a prescribed channel failure rate variance factor relative to the expected variance.

Dynamic adjustment of CCA threshold based on determined variance of channel transmit attempt failure rate relative to expected variance across available transmission channels

In one embodiment, a device in a network determines that a plurality of packets should be aggregated, each of the plurality of packets comprising a payload. The device generates, for each of the payloads, a sub-media access control (sub-MAC) header that comprises a sequence number and a frame check sequence (FCS). The device forms an aggregated packet that comprises a physical layer (PHY) header, a MAC header, the payloads, and the generated sub-MAC headers for the payloads. The device sends the aggregated packet to another device in the network.

Efficient transmission of small packets in low power and lossy networks

In one embodiment, a device in a mesh network rooted at a root node receives a subroot selection notification. The subroot selection notification indicates that the device should function as a root of a sub-directed acyclic graph (DAG) were a power outage to occur. The device determines that a power outage has occurred. The device forms, after determining that a power outage has occurred, a sub-DAG that is rooted at the device by establishing one or more other devices in the mesh network as routing children of the device in the sub-DAG. The device joins the sub-DAG to a DAG rooted at the root node.

Concurrent network reformation for low-power and lossy networks

A computer-implemented method of determining backoff windows in a wireless computer network is disclosed. The method comprises defining, by an access point in the wireless computer network, a plurality of collision patterns related to message transmission via one or more communication channels in the wireless computer network; detecting, by the access point, occurrence of one of the plurality of collision patterns involving a group of sender nodes in the wireless computer network that have each transmitted a message to the access point and received no acknowledgement message from the access point indicating successful transmission; setting to a first length a length of a backoff window for avoiding collision in data transmission based on a size of the group of sender nodes; sending a first message to a first plurality of nodes in the wireless computer network, the first message instructing performance of backoff during the backoff window having the first length.

Growing community of inventors

Shanghai, China

Nan Yi