VNX Do Not Support MCS (multiple connections per session)
Sometimes its hard to adapt VNX if you are coming from Netapp.
VNX do not support MCS type iscsi connection, only allowed MPIO reason is bellow from EMC Global Service.
To answer your question MCS Is not supported on EMC.
You cannot aggregate the iSCSI ports and they should be on separate subnets for redundancy.
MCS was designed to help with failover on the iSCSI level.
This is not handled by Failover software on the OS , either MPIO or Powerpath.
MC/S was designed at time, when most OS’ didn’t have standard OS level multipath. Instead, each vendor had its own implementation, which created huge interoperability problems. So, one of the goals of MC/S was to address this issue and standardize the multipath area in a single standard. But nowadays almost all OS’s has OS level multipath implemented using standard SCSI facilities, hence this purpose of MC/S isn’t valid anymore.
You can find the differences between MCS and MPIO