CCIE SP MPLS FAQ: Advanced MPLS Topics
Q1. Is it possible to restrict which prefixes have labels assigned to them so that label switching occurs to only certain destination prefixes?
Q2. What is the maximum frame size permissible across an Ethernet segment, and how can introducing MPLS affect forwarding across this type of media?
Q3. Which mechanism can you deploy to help determine the maximum allowable Path MTU for a packet?
Q4. What is the maximum size datagram, which does not support Path MTU discovery, that hosts can send?
Q5. What is the purpose of the DF bit?
Q6.In a frame-mode MPLS implementation, how are loopsdetected in the forwarding plane?
Q7. Is it possible to detect loops in the forwarding plane by using the TTL field in a cell-mode implementation of MPLS?
Q8. Using the hop-count TLV, an ATM-LSR can detect a loop in the control plane. What is the maximum number of permissible hops within a Cisco implementation, and can you change this maximum?
Q9. When using traceroute across an MPLS network, how can ICMP messages be forwarded back to the source of the traceroute?
Q10. What action does an aggregation LSR take if no label exists on an incoming packet?