Exam 300-410 topic 1 question 594 discussion

A seems OK, Penultimate Hop Popping will mean that the P before the PE pops the label as the P knows the PE can directly route it. The answer A will just indicate that the PE signals the P to do this.

PHP improves P router performance by eliminating the need for multiple label lookups. Here’s the reasoning: P routers are responsible for forwarding packets based on labels, but they don’t need to look up multiple labels when PHP is in place. By removing the outermost label before the packet reaches the last hop, the penultimate hop reduces the work that needs to be done by the last hop (the egress PE router), which only has to forward the packet to its final destination.

A is correct P router: is the second-to-last router in the MPLS path, removes the outer MPLS label before forwarding the packet to the last hop router (PE router). PE router: is the last hop router, which receives the packet with the outer label already removed and can directly forward the packet to its final destination without needing to process any MPLS labels. C is incorrect, P is the one which removes the outer label not PE. nice post to read: https://web.archive.org/web/20131213202855/http://journey4ccie.com/2013/02/04/mpls-vpns-and-issues-related-with-php-penultimate-hop-popping/

A is correct

voting C on this one.