Mansoor Mohsin

Reliable Broadcast in Wireless Mobile Ad Hoc Networks

We propose a single source reliable broadcasting algorithm for linear grid-based networks where a message is guaranteed to be delivered to all the nodes of the network. The nodes are mobile and can move from one grid point to another. The solution does not require the nodes to know the network size or its diameter. The only information a node has is its identity and its position. On average, only a subset of nodes transmit and they transmit only once to achieve reliable broadcast. The protocol is contention-free and energy-efficient. We show that reliable broadcast can be achieved in O(Dlog n) time-slots despite node mobility, where D is the diameter of the network and n the number of nodes.

Reliable multicast in mobile networks

This paper describes a distributed algorithm for reliable multicast in mobile cellular networks. In the proposed solution the multicast message is flooded to all the base stations over reliable channels. The base stations then collectively ensure that all mobile nodes belonging to the multicast group get the message. The originality of our solution is that it is fully decentralized. Each base station can independently decide when to flush a message from its buffer. Even if a node moves from one cell to another while a multicast is in progress, delivery of the message to the node is guaranteed. Simulation experiments show that using the proposed solution, memory requirements at the base stations are significantly smaller than by using centralized solutions.

The impact of mobility on the time complexity for deterministic broadcasting in radio networks

We study the time complexity for deterministic broadcasting algorithms in mobile radio networks. The broadcast operation consists of a source node successfully communicating its message to every other node. In multi-hop radio networks such as MANETs, the message may traverse multiple other nodes. Nodes have no prior knowledge besides the number n of nodes in the network and its diameter D. The problem we address has been extensively studied for static networks. Our work quantifies the impact of mobility. We consider three families of graphs: undirected graphs of constant contention degree, undirected graphs of non-constant contention degree and directed graphs of non-constant contention degree. We prove the lower bounds of Ω(n log n) time slots for the first family, Ω(n²/D² log D + D) time slots for the second and Ω(n²/D² log D + n log D) for the third. At the time of writing, the corresponding tightest lower bounds derived in the static case are, respectively, Ω(D log n), Ω(n log/log n / D) and Ω(n log D).

Service fabric: a distributed platform for building microservices in the cloud

We describe Service Fabric (SF), Microsofts distributed platform for building, running, and maintaining microservice applications in the cloud. SF has been running in production for 10+ years, powering many critical services at Microsoft. This paper outlines key design philosophies in SF. We then adopt a bottom-up approach to describe low-level components in its architecture, focusing on modular use and support for strong semantics like fault-tolerance and consistency within each component of SF. We discuss lessons learned, and present experimental results from production data.