Hopbased

Hopbased describes a family of methods, metrics, and rules in networking and distributed systems that base routing, forwarding, or search decisions on the number of intermediate nodes (hops) between a source and a destination. The central idea is that hop count can serve as a simple and scalable indicator of reachability, cost, or freshness of information, especially in environments with limited state or rapidly changing topology.

In routing, hop-based approaches use hop count as the primary metric for path selection. The best-known example is the Routing Information Protocol (RIP), which prefers routes with the fewest hops. More generally, hop-based strategies are used in overlay networks, content-distribution schemes, and delay-tolerant networks where limiting propagation to a certain hop radius reduces state and control overhead.

Implementation commonly involves incrementing a hop counter at each forward step, enforcing a maximum hop limit, or performing searches with a bounded depth. Some schemes also pair hop count with time-to-live (TTL) values to bound dissemination and prevent excessive spreading.

Advantages of hopbased designs include simplicity, predictable behavior, and low state requirements, making them suitable for resource-constrained devices and rapidly changing networks. Limitations include insensitivity to latency, bandwidth, and congestion, which can lead to suboptimal routes. In large or dynamic networks, hop-based methods can struggle with scalability and robustness unless combined with other metrics or safeguards to avoid routing loops and hop creep.

See also: hop count, RIP, TTL, routing metrics.