Which two LISP infrastructure elements are needed to support LISP to non-LISP internetworking? (Choose two)
- A. PETR
- B. PITR
- C. MR
- D. MS
- E. ALT
Explanation: In this question we suppose that we only need to send packets from LISP site to non-LISP site successfully. We don‘t care about the way back (if we care about the way back then all PETR, PITR, MS & MR are needed).
Proxy Egress Tunnel Router (PETR): A LISP device that de-encapsulates packets from LISP sites to deliver them to non-LISP sites.
When the xTR in LISP Site 1 want to sends traffic to Non-LISP site, the ITR (not PETR) needs a Map Resolver (MR) to send Map Request to. When the ITR (the xTR in LISP Site 1 in the figure above) receives negative MAP-Reply packet from MR, it caches that prefix and map it to the PETR.
Good reference: Here
More Questions: CCNP 350-401 Dumps