0 Replies Latest reply on Aug 5, 2016 12:13 AM by mpoleg

    Multicast via switch between two Windows machines does not work




      I encountered an issue with IB multicast data between 2 Windows computers with ConnectX-3 Mellanox adapters via  IB switch.

      Multicast does not work: Mellanox counters on the sender machine measure an expected rate of outgoing messages but a receiver machine' counters keep silence.

      OpenSM was running on the third (Linux) machine.


      A receiver application creates a multicast group:

      using group's MGID

      member_rec.qkey = 0xb0b10000

      member_rec.pkey = 0xFFFF


      A sender application then sends messages to that group without joining it:

      using group's MGID

      dgrm.ud.remote_qp = 0xFFFFFF00 (instead of 0xFFFFFF as specified in "InfiniBandTM Architecture Specification Volume 1 Release 1.2.1")

      dgrm.ud.remote_qkey = 0

      dgrm.ud.pkey_index = 0


      Multicast works as expected when the same two machines connect to each other directly (without a switch).

      Also multicast traffic is successfully transferred on the only one of these machines using a loopback feature.

      Unreliable datagram communication works without problems.

      IPoIB multicast works without problems


      May be someone knows how to make the switch to transfer IB  multicast data to subscribers?