Source Packet Routing in Networking (SPRING) architecture leverages
the source routing paradigm. A node steers a packet through a
controlled set of instructions, called segments, by prepending the
packet with SPRING header. A segment can represent any instruction,
topological or service-based. A segment can have a local semantic to
the SPRING node or global within the SPRING domain. SPRING allows to
enforce a flow through any topological path and service chain while
maintaining per-flow state only at the ingress node to the SPRING
domain. The objective of this document is to illustrate some use cases
that need to be taken into account by the Source Packet Routing in
Networking (SPRING) architecture.