Which two LISP infrastructure elements are needed to support LISP to non-LISP internetworking? (Choose two)

A Proxy Egress Tunnel Router (PETR) is a specialized LISP device that encapsulates traffic from a LISP site destined for a non-LISP network and sends it into the traditional internet, acting as the egress point for LISP-originated traffic.

A Proxy Ingress Tunnel Router (PITR) is used when a non-LISP site initiates communication to a LISP site; it receives traffic from a non-LISP network, encapsulates it, and sends it into the LISP domain.

A Map Resolver (MR) is a LISP infrastructure device that receives Map-Request messages from Ingress Tunnel Routers (ITRs) or PITRs, and then forwards these requests to the appropriate Map Servers (MS) to resolve EID-to-RLOC mappings, which is crucial for LISP routers to find the RLOCs of PETRs or other LISP sites to forward traffic correctly.

A Map Server (MS) stores EID-to-RLOC mappings for LISP sites and responds to Map-Requests; while crucial for LISP operation, it doesn't directly handle the internetworking encapsulation/decapsulation for LISP to non-LISP traffic like a PETR.

ALT (Alternative Logical Topology) is a routing protocol used by Map Servers and Map Resolvers to find each other and exchange mapping information, but it is an internal LISP mechanism rather than an infrastructure element directly responsible for LISP to non-LISP internetworking.