Home > Storage > PowerScale (Isilon) > Product Documentation > Networking > PowerScale: Ethernet Back-end Network Overview > Ethernet back end
In legacy versions of Isilon OneFS, back-end data traffic uses SDP and IPoIB for management. SDP has fast failover and incorporates various InfiniBand-only features that ensure optimum performance. However, because SDP only works over InfiniBand, a new method was required to get optimal performance over the Ethernet back end. For this reason, the new generation of PowerScale platforms now uses RBM over TCP on the back-end switches.
RBM now uses TCP, and the TCP stack has been enhanced to provide the performance required to support the cluster communication. All the modifications of the TCP stack have been made while conforming to the industry standard specification of the stack. The back-end and front-end networks will use the same TCP stack and modifications to the performance of the back-end TCP stack should not affect TCP traffic on the front end. RBM over Ethernet will still provide fast failover.