The observation that topology changes more rapidly on a mobile, wireless network than on wired networks, where the use of Distance Vector (DV), Link State (LS), and Path Vector routing algorithms is well-established, motivates this body of work. Dynamic Source Routing (DSR), Ad-Hoc On-Demand Distance Vector Routing (AODV), and the Zone Routing Protocol (ZRP) all eschew constantly pushing current topology information network-wide. Caching reduces the routing protocols’ message load in two ways: it avoids pushing topological information where the forwarding load does not require it (e.g., at idle routers), and it often reduces the number of hops between the router that has the needed topological information and the router that requires it (i.e., a node closer than a changed link may already have cached the new status of that link).
Routing protocol message cost: How many routing protocol packets does a routing algorithm send? On-demand ad-hoc routing algorithms require state at least proportional to the number of destinations a node forwards packets toward, and often more, as in the case in DSR, in which a node aggressively caches all source routes it overhears to reduce the propagation scope of other nodes’ flooded route requests. The state required is negligible, and dependent on the density of nodes in the wireless network, not the total number of destinations in the net-work. On networks where multi-hop routing is useful, the number of neighbors within a node’s radio range must be substantially less than the total number of nodes in the network.
Article talks about “routing, networks, packets, nodes, forwarding”
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