MPLS-Enabled Applications: Emerging Developments and New Technologies

2.12. STUDY QUESTIONS

1. Referring to RFC 3209, what is the protocol encoding decision that restricts the number of LSPs that an LSR can be head end for?

2. Compare the following approaches for keeping traffic within one geographical area: (a) IGP metric manipulation and (b) link coloring.

3. Preemption is applied at LSP setup time, when RSVP signaling is applied. The specifications do not define what the behavior should be when an LSP is preempted. One option is to immediately confiscate the resources and tear down the forwarding state of the preempted LSP and inform the head end that the LSP was preempted. This approach is sometimes referred to as 'hard preemption'. The other option is to inform the head end that the LSP is preempted and needs to be moved, but only tear down the forwarding state at the node where the LSP was preempted after a delay (unless it is removed by the head end before). This approach is sometimes referred to as 'soft preemption'. What would be the rationale for each approach?

4. Setting up LSPs with bandwidth reservations in the control plane does not ensure that resources are reserved in the data plane. Two approaches exist for making sure the data path is not 'overrun': (a) admission control of services into the LSPs and (b) policing. Compare the two approaches.

5. When advertising the LSP into the IGP, its metric can be set in one of the following two ways: (a) it can inherit the metric of the underlying IGP path or (b) it can have a fixed metric. What are some of the ...