Hybrid Routing, is professionally known as balanced-hybrid routing, This is a combination of distance-vector routing, which works by sharing its knowledge of the entire network with its neighbors and link-state routing which works by having the routers tell every other router on the network about its closest neighbors. Commonly known as forming neighbor relationship.
Hybrid Routing is a third classification of routing algorithm.
Hybrid routing protocols use distance-vectors for more accurate metrics to determine the best paths to destination networks, and report routing information only when there is a change in the topology of the network. Hybrid routing allows for rapid convergence but requires less processing power and memory as compared to link-state routing.
A Hybrid Routing protocol has the advantages of both Distance Vector and Link State Routing protocols and merges them into a new protocol. Typically, hybrid routing protocols are based on a Distance Vector protocol but contain many of the features and advantages of Link State Routing protocols.
Example: EIGRP (Enhanced Interior Gateway Routing Protocol).
Enhanced Interior Gateway Routing Protocol (EIGRP) is considered as a Hybrid Routing Protocol because EIGRP has characteristics of both Distance Vector and Link State Routing Protocols.
Enhanced Interior Gateway Routing Protocol (EIGRP) doesn’t send Link State Advertisement (LSA) packets as Open Shortest Path First (OSPF) does, but Enhanced Interior Gateway Routing Protocol (EIGRP) sends traditional Distance Vector updates containing information about networks plus the cost of reaching them from the perspective of the advertising router.
Enhanced Interior Gateway Routing Protocol (EIGRP) has Link State characteristics also. Enhanced Interior Gateway Routing Protocol (EIGRP) synchronizes routing tables between neighbors at startup, and then it sends specific updates when a network topology change happen.