Per http://www.open-mpi.org/community/lists/devel/2007/12/2698.php and

this thread:
http://www.open-mpi.org/community/lists/devel/2007/12/2807.php, set
TCP's exclusivity to LOW+100 and SCTP's exclusivity to LOW.

This commit was SVN r16942.

ompi/mca/btl/sctp/btl_sctp_component.c

@@ -242,7 +242,7 @@ int mca_btl_sctp_component_open(void)
         mca_btl_sctp_param_register_int ("if_11", 0);
 
     /* have lower exclusivity than tcp */
-    mca_btl_sctp_module.super.btl_exclusivity = MCA_BTL_EXCLUSIVITY_LOW - 1;
+    mca_btl_sctp_module.super.btl_exclusivity = MCA_BTL_EXCLUSIVITY_LOW;
     mca_btl_sctp_module.super.btl_eager_limit = 64*1024;
     mca_btl_sctp_module.super.btl_min_send_size = 64*1024;
     mca_btl_sctp_module.super.btl_max_send_size = 128*1024;

ompi/mca/btl/tcp/btl_tcp_component.c

@@ -244,7 +244,7 @@ int mca_btl_tcp_component_open(void)
             " where Open MPI will open sockets.",
             64*1024 - mca_btl_tcp_component.tcp6_port_min - 1);
 #endif
-    mca_btl_tcp_module.super.btl_exclusivity =  MCA_BTL_EXCLUSIVITY_LOW;
+    mca_btl_tcp_module.super.btl_exclusivity =  MCA_BTL_EXCLUSIVITY_LOW + 100;
     mca_btl_tcp_module.super.btl_eager_limit = 64*1024;
     mca_btl_tcp_module.super.btl_min_send_size = 64*1024;
     mca_btl_tcp_module.super.btl_max_send_size = 128*1024;