SXP project is an effort to enhance Opendaylight platform with IP-SGT bindings that can be learned from connected SXP-aware network nodes. Current implementation supports SXP protocol version 4 according to theSmith, Kandula - SXP IETF I-D. All protocol legacy versions 1-3 are supported as well. Additionally, version 4 adds bidirectional connection type as an extension of a unidirectional one.
The documentation can be found on Architecture page.