The primary function of IGPs is to?

The primary function of Interior Gateway Protocols (IGPs) is to gather and disseminate routing information within an autonomous system. IGPs operate within a single administrative domain, allowing routers within that domain to share information about network reachability and paths. This enables them to build and maintain accurate routing tables, ensuring efficient and effective routing of data packets within the autonomous system.

In contrast, the other options relate to different networking functions. For example, facilitating external routing communications pertains more to Exterior Gateway Protocols (EGPs), which handle routing between different autonomous systems. Connecting different internet service providers also falls under the domain of EGPs, focusing on the exchange of routing information across broader internet boundaries. Lastly, monitoring network security protocols does not align with the primary responsibilities of IGPs, which are centered on routing rather than security. Thus, the main role of IGPs is accurately reflected in the option regarding gathering and sharing routing information within an autonomous system.