WLAN Mesh Networks (WMNs) are a promising network architecture for IoT applications due to their self-healing and robust network formation capabilities. The IEEE 802.11s amendment standard integrates mesh functionality into the WLAN MAC layer, ensuring seamless peering and routing. Initially designed for testing, the Linux implementation of IEEE 802.11s includes basic peer link blocking mechanisms. Based on this, we present a new MAC address filtering approach for reliable topology control in WLAN mesh networks. Our modifications to the Linux kernel enable persistent link blocking and bidirectional link teardown, preventing the sporadic establishment of unwanted connections. Real-world experiments demonstrate the effectiveness of our approach.

Mesh networks based on the wireless local area network (WLAN) technology, as specified by the standards amendment IEEE 802.11s, provide for a flexible and low-cost interconnection of devices and embedded systems for various use cases. To assess the real-world performance of WLAN mesh networks and potential optimization strategies, suitable testbeds and measurement tools are required. Designed for highly automated transport-layer throughput and latency measurements, the software FLExible Network Tester (Flent) is a promising candidate. However, so far Flent does not integrate information specific to IEEE 802.11s networks, such as peer link status data or mesh routing metrics. Consequently, we propose Flent extensions that allow to additionally capture IEEE 802.11s information as part of the automated performance tests. For the functional validation of our extensions, we conduct Flent measurements in a mesh mobility scenario using the network emulation framework Mininet-WiFi.

WLAN mesh networks are one of the key technologies for upcoming smart city applications and are characterized by a flexible and low-cost deployment. The standard amendment IEEE 802.11s introduces low-level mesh interoperability at the WLAN MAC layer. However, scalability limitations imposed by management traffic overhead, routing delays, medium contention, and interference are common issues in wireless mesh networks and also apply to IEEE 802.11s networks. Possible solutions proposed in the literature recommend a divide-and-conquer scheme that partitions the network into clusters and forms smaller collision and broadcast domains by assigning orthogonal channels. We present CHaChA (Clustering Heuristic and Channel Assignment), a distributed cross-layer approach for cluster formation and channel assignment that directly integrates the default IEEE 802.11s mesh protocol information and operating modes, retaining unrestricted compliance to the WLAN standard. Our concept proposes further mechanisms for dynamic cluster adaptation, including subsequent cluster joining, isolation and fault detection, and node roaming for cluster balancing. The practical performance of CHaChA is demonstrated in a real-world 802.11s testbed. We first investigate clustering reproducibility, duration, and communication overhead in static network scenarios of different sizes. We then validate our concepts for dynamic cluster adaptation, considering topology changes that are likely to occur during long-term network operation and maintenance.

In this paper, we analyze the state of the art in distributed ledger technologies and blockchains and investigate potential applications in the Internet of Things (IoT) domain. Afterwards, we discuss interoperability of blockchains, and their use in smart contracts, and artificial intelligence.

WLAN mesh networks are one of the key technologies for upcoming smart city applications and characterized by a flexible and low-cost deployment. The amendment IEEE 802.11s (.11s) introduces low-level mesh interoperability at the WLAN MAC layer. However, scalability limitations imposed by management traffic overhead, routing delays, medium contention, and interference are common issues in wireless mesh networks and also apply to. 11s networks. Possible solutions proposed in research recommend a divide-and-conquer scheme that partitions the network into clusters and forms smaller broadcast and collision domains by assigning different channels. We present CHaChA, a distributed cross-layer approach for clustering and channel assignment that directly integrates the default. 11s mesh protocol information and operation modes, retaining unrestricted compliance to the standard. The practical performance and implied benefits of CHaChA are demonstrated in a real-world testbed.