Which two features will be used when defining SR-TE explicit path hops if the devices are using IP unnumbered interfaces? (Choose two.)

A router ID identifies the router itself, but 'labels' and 'node address' are more specific to defining explicit hops in an SR-TE path, especially when interfaces are unnumbered.

Labels, specifically Segment Identifiers (SIDs) like Node SIDs and Adjacency SIDs, are fundamental to Segment Routing-Traffic Engineering (SR-TE) for defining explicit paths and telling a router how to forward traffic. They explicitly dictate the path through the network.

With IP unnumbered interfaces, individual interface IP addresses are not available for hop specification. Instead, the unique identifier for a router, typically its loopback interface IP address (the node address), is used to specify a node in the explicit path, corresponding to a Node SID in SR.

The next hop address is usually an interface's IP address. For IP unnumbered interfaces, their specific IP is not available for direct use as a hop identifier; instead, labels or the node's loopback address are used.

Specifying an output interface directly is less granular and flexible than using Segment Routing labels and node addresses to define an explicit path, particularly with unnumbered interfaces where the interface IP itself is not unique.