Q : How simple can X get? A: The Stable Paths Problem (SPP)
- A graph of nodes and edges,
- Node 0, called the origin,
- For each non-zero node, a set or permitted paths to the origin. This set always contains the “null path”.
- A ranking of permitted paths at each node. Null path is always least preferred. (Not shown in diagram)
When modeling BGP : nodes represent
BGP speaking border routers, and 0 represents
a node originating some address block
least preferred (not null)