User Manual

Driver FeaturesRev 2.1-1.0.6

Mellanox Technologies

• VLAN simulation over an InfiniBand network via child interfaces

• High Availability via Bonding

• Varies MTU values:

• up to 4k in Datagram mode

• up to 64k in Connected mode

• Uses any ConnectX® IB ports (one or two)

• Inserts IP/UDP/TCP checksum on outgoing packets

• Calculates checksum on received packets

• Support net device TSO through ConnectX® LSO capability to defragment large data-

grams to MTU quantas.

• Dual operation mode - datagram and connected

• Large MTU support through connected mode

IPoIB also supports the following software based enhancements:

• Giant Receive Offload

• NAPI

• Ethtool support

4.3.2 IPoIB Mode Setting

IPoIB can run in two modes of operation: Connected mode and Datagram mode. By default,

IPoIB is set to work in Datagram, except for Connect-IB™ adapter card which uses IPoIB with

Connected mode as default.

For better scalability and performance we recommend using the Datagram mode. However, the

mode can be changed to Connected mode by editing the file

/etc/infiniband/openib.conf

and setting ‘SET_IPOIB_CM=yes’.

The

SET_IPOIB_CM parameter is set to “auto” by default to enable the Connected mode for Con-

nect-IB™ card and Datagram for all other ConnectX® cards.

After changing the mode, you need to restart the driver by running:

To check the current mode used for out-going connections, enter:

/etc/init.d/openibd restart

cat /sys/class/net/ib<n>/mode