The Source Packet Routing in NetworkinG (SPRING) Working Group is the
home of Segment Routing (SR) using the MPLS (SR-MPLS) and IPv6 (SRv6)
data planes. The SPRING WG is responsible for defining new applications
for, and specifying extensions to, Segment Routing technologies. It also
serves as a forum to discuss SR-MPLS network operations. The SRv6
Operations (srv6ops) WG is dedicated to the operational aspects of
deploying and managing SRv6 networks.

The work in the SPRING WG should avoid modification to existing data
planes that would make them incompatible with existing deployments.
Where possible, existing control and management plane protocols must
be used within existing architectures to implement the SPRING
function. Any modification of -or extension to- existing
architectures, data planes, or control or management plane protocols
should be carried out in the WGs responsible for the architecture,
data plane, or control or management plane protocol being modified
and in coordination with the SPRING WG, but may be done in SPRING WG
after agreement with all the relevant WG chairs and responsible Area
Directors.

The SPRING WG defines procedures that allow an SR node to steer a packet
through an SR Policy instantiated as an ordered list of instructions
called segments without needing per-path state information at transit
nodes. A network comprising only SR nodes can achieve full path
control (through loose or strict path specification). However, SR
nodes must interoperate through loose routing in existing networks.

By default, Segment Routing operates within a trusted domain and
requires the enforcement of a strict boundary to prevent Segment
Routing packets from entering the trusted domain [rfc8402]. Some
deployments may involve multiple trusted domains and the use of
cross/inter-domain segments. Documents which deal with such
situations need to include a risk analysis and use mechanisms to
validate that the segment list is provided by an authorized entity
and has not been modified in transit.

The SPRING WG will manage its specific work items based on WG
engagement and successful adoption.

The SPRING WG is expected to coordinate and collaborate closely
with the following WGs:

* mpls on the MPLS data plane and associated extensions
* 6man on the IPv6 data plane and associated extensions
* srv6ops on SRv6 operations

As needed, the WG will also collaborate with other WGs to develop
extensions and other SR-related solutions.