EGP and BGP
As mentioned, Exterior Gateway Protocols transfer data between networks (between autonomous systems).
EGP-2, an early version of Exterior Gateway Protocol, requests information from neighboring routers every 120 to 480 seconds.
This protocol exchanges entire routing tables during the transactions. The tables consist of routers, addresses, and cost metrics associated with each router.
Border Gateway Protocol (BGP) also provides a list of routers, addresses that can be reached, and cost metrics.
Instead of transmitting the entire routing table, however, BGP only sends updates for the affected parts of the routing tables.