The Internet and Its Protocols

486 Chapter 9 Multiprotocol Label Switching (MPLS)

across an LSR, then either solution may be suitable, depending on implementa-

tion, with L-LSPs making it possible to apply a coarser filter on traffic without

the need to examine packets.

Using MPLS it is possible to establish traffic protection schemes that protect

individual LSPs or groups of LSPs. One model for this would protect only the

traffic having certain PSC and drop characteristics. In this model it would be

impossible to protect only some of the traffic on an LSP, and the use of L-LSPs

may be required to differentiate ...