draft-ietf-mpls-arch-00 rfc3031

1. Loop Control
    a. TTL(Time to Live) -1
2. Loop Prevention
    a. LSR’s maintain for each of their LSP’s an LSR id list. The list is a list of all the LSP’s downstream from this LSR on a given LSP. The LSR id list is used to prevent the information of switched path loops.
3. Merging and Non-Merging LSRs
4. Ru: upstream LSR
5. Rd: downstream LSR
6. Hierarchy: LSP Tunnels within LSPs
7. Label Distribution Peering and Hierarchy
8. MPLS supports two ways to distribute labels at different layers of the hierarchy: Explicit Peering and Implicit Peering.
9. Why More than one Label Distribution Protocol?
    (3.29.1 3.29.2 3.29.3 3.30)
10. MPLS and Explicitly Routed LSPs: There are a number of reasons why it may be desirable to use explicit routing instead of hop by hop routing. For example, this allows routes to be based on administrative policies, and allows the routes that LSPs take to be carefully designed to allow traffic engineering.