Exactprep 300-410 Questions

+ allows an LSR to remove the label before forwarding the packet: penultimate hop popping

+ accepts unlabeled packets and imposes labels: label edge router

+ group of packets that are forwarded in the same manner: forwarding equivalence class

+ receives labeled packets and swaps labels: label switch router

Explanation

A label edge router (LER, also known as edge LSR) is a router that operates at the edge of an MPLS network and acts as the entry and exit points for the network. LERspush an MPLS label onto an incoming packet and pop it off an outgoing packet.

A forwarding equivalence class (FEC) is a term

The “transport output none” command prevents any protocol connection made from R1.

Therefore our SSH connection to 192.168.12.2 was refused. In order to fix this problem we can

configure “transport output ssh” under “line console 0” of R1.

Note: The parameter “-l” specifies the username to log in as on the remote machine.

According to this question, uRPF is running in strict mode because packets are dropped even

when that route exists in the routing table. Maybe packets are dropped because the receiving

interface is different from the interface the local router uses to send packets to that destination.

The ip verify unicast source reachable-via rx command enables Unicast RPF in strict mode.

To enable loose mode, administrators can use the any option (ip verify unicast source

reachable-via any). In loose mode, it doesn’t matter if we use this interface to reach the source

or not.

The allow-default option allows the use of the default

route in the source verification process.