Through which two configuration elements are off-net calls routed in inbound and outbound direction respectively?

The inbound CSS assigned to a gateway or trunk determines which partitions and patterns are accessible when a call arrives from the PSTN, controlling how inbound off-net calls are steered into the CUCM dial plan. Route groups aggregate gateways and trunks into logical pools that route lists select from when sending outbound calls to the PSTN, making them the primary outbound routing element. Together, inbound CSS and route groups serve as the respective configuration elements for inbound and outbound off-net call routing.

Device pools group devices by region, location, and media resource settings and have no direct role in controlling the routing direction of off-net calls.

Route lists select among route groups and are part of the outbound routing chain, but they are not the elemental pair that directly corresponds to inbound CSS for bidirectional off-net routing.

Route patterns match dialed digit strings to initiate outbound routing, but they work in conjunction with route lists and route groups rather than serving as the outbound counterpart to inbound CSS.