Cisco Enterprise Network Core Technologies (ENCOR) Practice Exam

An Ingress Tunnel Router (ITR) in LISP (Locator/Identifier Separation Protocol) primarily encapsulates packets that are destined for an Endpoint Identifier (EID) address. This function is crucial in the LISP architecture because it allows for the separation of address spaces, where the EID represents the actual destination, while the Routing Locator (RLOC) corresponds to the network location. By encapsulating the packets with a LISP header, the ITR ensures that the data packets can be properly routed across the LISP network, maintaining the separation of control and data planes.

Additionally, ITRs are responsible for sending packets to the appropriate Egress Tunnel Router (ETR), which then decapsulates them for delivery to the destination EID. This encapsulation process allows for better mobility and scalability of the network, as it abstracts the addressing schema and enables more efficient routing without impacting the core network infrastructure.

Other functions mentioned in the choices pertain to different components and processes within the LISP framework, which helps to clarify the specific role of the ITR in the encapsulation process.