Multiple Connections per Session
The Linux SCSI Target Wiki
Multiple Connections per Session (MC/S) means using multiple communication paths in a single session ("I_T Nexus"). Architectural session command ordering is preserved across those communication paths.
Multiple iSCSI connections per iSCSI session (MC/S) means creating multiple communication paths across TCP, SCTP or iSER & RCaP connections. Session-wide command (CmdSN defined) ordering is preserved per RFC 3720 to ensure in-order delivery of tasks from an SCSI Initiator Port to an SCSI Target Port as defined by the SCSI Architecture Model, in which iSCSI provides the SCSI transport.
The requirements as defined by RFC-3720 for non-ERL dependent MC/S support are not limited to the following:
- Add additional connections on the fly with active+inactive IO (non-leading login)
- Remove connections on the fly with active+inactive IO (explict logout)
- Remove connections on the fly on a different connection with active+inactive IO (different CID explict logout)
- Restart session+connections during single connection failure (session reinstatement)
- Multiple connection sessions to the same and different network portals (iSCSI trunking)
RFC 3720: Internet Small Computer Systems Interface (iSCSI)