RIP — Shortcomings and Their Fixes

RIP (Routing Information Protocol) is a distance-vector IGP that uses hop count as its metric with a maximum of 15 hops (16 = unreachable) and exchanges full routing tables every 30 s.

#	Shortcoming of RIP	Consequence	Corresponding fix / remedy
1	Metric is only hop count (max 15) — ignores bandwidth, delay, congestion	A 2-hop low-speed link may be preferred over a 1-hop high-speed link; large networks unreachable	Use a richer metric: OSPF/EIGRP use cost/bandwidth+delay; RIP has no real fix (limitation of the protocol)
2	Count-to-infinity problem on link failure	Routers keep incrementing an unreachable metric, taking minutes to converge	Split horizon with poison reverse, hold-down timers, triggered updates; alternatively use LS routing (OSPF) which does not suffer from it
3	Convergence is slow (30 s periodic updates + timers)	Transient black holes and routing loops during topology change	Triggered (flash) updates on change, shorter timers; or switch to link-state protocols that flood changes immediately
4	Full routing table advertised every 30 s regardless of change	Wasteful bandwidth, especially on slow/wireless links	Triggered updates (send only on change); route redistribution/filtering; VLSM support via RIPv2
5	No VLSM / classful routing (RIPv1)	Cannot summarise or support variable-length masks, poor address utilisation	RIPv2 — carries subnet masks in updates, supports CIDR summarisation, authentication, and multicast (224.0.0.9)
6	No authentication of updates (RIPv1)	Susceptible to rogue/malicious routing advertisements	RIPv2 authentication (plain/md5) of routing updates
7	No support for multiple metrics / equal-cost paths; simple Bellman–Ford only; loop-free property weak	Sub-optimal routes	Use OSPF/IS-IS/EIGRP for large or multi-vendor networks

Summary: RIP's core weaknesses — hop-count metric, slow periodic convergence, and count-to-infinity — are addressed within the RIP family by triggered updates, split horizon/poison reverse, hold-down timers, RIPv2 (VLSM/CIDR/authentication); the complete engineering fix is to migrate to a link-state protocol (OSPF) for larger networks.