LOADng is an acronym for Lightweight On-Demand Ad hoc Distance Vector Routing Protocol – Next Generation. The AODV (Ad hoc On-Demand Distance Vector) routing protocol, which is essentially a distance vector routing technique, served as inspiration for this protocol. Unlike AODV, LOADng was designed as a reactive protocol with the constraints of Mobile Ad hoc Networks in mind (MANETs). The LOADng process begins with a LOADng router initiating route discovery through the creation of route requests (RREQs). The router sends packets to its closest connected neighbors, who in turn send packets to their one-hop neighbors. This procedure is repeated until the desired location has been reached. The destination sends a route reply (RREP) packet to the RREQ originating router after receiving the RREQ packet. The route error (RERR) messages are created and forwarded to the origin router as a continuation of a route between the origin and the destination is discovered to be down.
AODV Protocol:
The AODV protocol only creates routes between nodes if source nodes request them. As a result, AODV is regarded as an on-demand algorithm, as it generates no additional traffic for communication over connections. The routes are maintained for as long as the sources demand them. They also construct trees to link members in multicast groups. To maintain route freshness, AODV employs sequence numbers. They’re self-starting and loop-free, and they can scale to a large number of mobile nodes. Networks in AODV remain quiet until connections are made. Network nodes in need of connections broadcast a connection request. The remaining AODV nodes forward the message and keep track of which node made the connection request. As a result, a series of temporary routes back to the asking node is created.
Working of LOADng:
The working of the LOADng protocol is described below:
- Network route discovery in both directions between a source and a destination.
- Establishing and maintaining a path between the source and the destination.
- Only when data must be sent or a route to the destination is down does the network generate control and signaling traffic.
LOADng routing mechanism
Principle of Operation of LOADng:
- When a data packet from a local data source is received for transmission to a destination whose routing entry (a tuple) is not present with it, a LOADng router sends an RREQ over all of its LOADng interfaces. The various forward interfaces are numbered to identify the destination from the source LOADng node.
- The destination address obtained from the local source is encoded by the RREQ in the packet.
- Upon receiving an RREQ, the routing set that manages the routing entries at each LOADng router updates or inserts an entry (with information about the originating address and the nearest LOADng router). This also makes it possible to keep track of the reverse journey between the source and the destination.
- If the packets are intended for a local interface of a LOADng router, the received RREQ initiates a check of the destination address, and an RREP is sent back using the reverse route if the packets are intended for a local interface of a LOADng router.
- If the target address is not local, it is sent in a hop-by-hop unicast manner to other LOADng interfaces through flooding.
- When an RREP is received, the forward path toward the RREP’s origin is noted in the routing entry, along with the LOADng router that transmitted the message. RREQ and RREP messages are also used to update the route metrics. The LOADng selects the appropriate metric for usage.