Which plane does a router use to exchange topology information to build a routing table?

The back plane (or backplane) is a physical component within the router that connects internal hardware modules, not a logical plane for network information exchange.

The data plane (or forwarding plane) is responsible for forwarding user traffic based on the decisions made by the control plane and information in the routing table, but it does not exchange topology information itself.

The control plane of a router is where routing protocols (like OSPF, EIGRP, BGP) operate to exchange topology information with other routers. This information is processed to construct and maintain the routing table, which contains the best paths to network destinations.

The management plane is used for managing the device itself, including configuration, monitoring, and troubleshooting, typically via protocols like SSH, Telnet, SNMP, or Syslog, and does not handle routing information exchange.