Assuming TTL propagation is enabled, how does MPLS ensure the integrity of the TTL loop
detection
mechanism in IP?
A.
The TTL field in the MPLS header is set to 255. This field is decremented at each hop in the
MPLS cloud. If
the TTL has not expired, its value is copied back into the IP header.
B.
The TTL field in the IP header is copied to the TTL field in the MPLS header. This field is
passed
transparently through the MPLS cloud. The TTL value is copied back into the IP header.
C.
The TTL field in the IP header is copied to the TTL field in the MPLS header. This field is
decremented by one in the MPLS cloud. If the TTL has not expired its value is copies back into the
IP header.
D.
The TTL field in the IP header is copied to the TTL field in the MPLS header. This field is
decremented at each hop in the MPLS cloud. If the TTL has not expired, its value is copied back
into the IP header.