Which attribute determines the trust level of routing information from different protocols on a router?

• A. The speed of the routing protocol
• B. The default administrative metric for all routes
• C. The trust level assigned to routing information from a protocol
• D. The TTL limit for routes

Answer: (C)

Trust in routing information comes from how much you assign to the source of that information. A router marks each routing protocol with a trust level, and this determines whether updates from that protocol are accepted and preferred when multiple sources advertise the same destination. In practice, this is expressed as the administrative distance for each protocol: a lower distance means you trust that protocol more, so its routes win over those learned from less trusted sources, even if the metrics inside other protocols would suggest a different choice.

The other factors don’t determine trust: the speed of a routing protocol affects how fast updates propagate, not how trustworthy the updates are; a default metric influences route selection within a protocol but not across protocols; and a TTL limit governs how long a route update remains usable rather than how trustworthy its source is.