On Mon, 2008-09-15 at 15:50 -0400, Kumar, Amit H. wrote: > > > > The MTU reported by "ifconfig ib0" is the MTU used by the Linux > > TCP/IP network stack. The MTU reported by ibv_devinfo is the > > MTU that the hardware is capable of sending. This is limited > > to 4K by the Infiniband specification. The reason the network > > stack can have a higher MTU is that ib_ipoib is using the RC > > QP protocol to send IP messages larger than the hardware MTU. > > If you use "datagram" mode for ib_ipoib, you will see that > > the network stack MTU is limited to the hardware MTU - 4. > > Thank you Ralph!!! As far as common applications taking advantage of ib_ipoib > Does it help using RC QP with a higher MTU than the hardware MTU? > > Does an Application, which uses Sockets API, by default make use of ib_ipoib, > if it is enabled ? > > Is there any essential difference between IPoIB and ib_ipoib, or is it just a > matter of usage ? > > Thank you, > Amit
IPoIB is ib_ipoib. The first is the name in the IB spec. the second is the name of the kernel module. ib_ipoib just looks like another sockets network device to Linux so Sockets API calls work normally (you just need to use the IP address of the ib0 device). The reason a larger network MTU helps is because the Linux network stack is more efficient when using larger MTUs. _______________________________________________ general mailing list [email protected] http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
