Module 3: Internet of Things [15CS81] © Mr. Nischaykumar Hegde, Dept. of CSE, VCET Puttur 182 Hop-by-hop scheduling: A node reserves a path to a destination node multiple hops away by requesting the allocation of cells in a schedule at each intermediate node hop in the path. The protocol that is used by a node to trigger this scheduling mechanism is not defined at this point. In addition to schedule management functions, the 6TiSCH architecture also defines three different forwarding models. Forwarding is the operation performed on each packet by a node that allows it to be delivered to a next hop or an upper-layer protocol. The forwarding decision is based on a preexisting state that was learned from a routing computation. There are three 6TiSCH forwarding models: Track Forwarding (TF): This is the simplest and fastest forwarding model. A “track” in this model is a unidirectional path between a source and a destination. This track is constructed by pairing bundles of receive cells in a schedule with a bundle of receive cells set to transmit. So, a frame received within a particular cell or cell bundle is switched to another cell or cell bundle. This forwarding occurs regardless of the network layer protocol. Fragment forwarding (FF): With FF, a mechanism is defined where the first fragment is routed based on the IPv6 header present. The 6LoWPAN sub layer learns the next-hop selection of this first fragment, which is then applied to all subsequent fragments of that packet. Otherwise, IPv6 packets undergo hop-by-hop reassembly. This increases latency and can be
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- Computer Science, Internet Protocol Suite, VCET PUTTUR, Mr. Nischaykumar Hegde