Miercom was engaged by Dell Networking to independently test its latest data-center switch – the Z9500 10/40 Gigabit Ethernet Fabric Switch, the high-end model in the vendor's Z Series and the highest-density, highest-throughput switch produced by Dell Networking to date.

Introduced in March 2014, the Z9500 supports up to 132 x 40GE ports – four times the capacity of the Z9000, the other member of the Z Series. The Z9500 delivers 10.4 Tbps (Terabits/s) full duplex of switching throughput and a non-blocking switching fabric more than four times more than the predecessor Z9000.

Previous testing of a Dell Networking switch occurred in 2013. This was the S6000 10/40 Gigabit Ethernet Top-of-Row/End-of Rack switch, the top model in the vendor's S Series and the first supporting high density 40GE ports.

The tests of both the Z9500 and S6000 are part of our ongoing evaluation of switches that support 40GE – the Miercom 40GE Switch Industry Assessment.

We tested the Z9500 in both store-and-forward and cut-through operating modes. The earlier S6000 was successfully tested in store-and-forward mode only; cut through mode was not available at the time of testing. Dell states that cut-through mode has since been released.

Our testing of the Z9500 primarily addressed performance and energy efficiency.For performance testing, traffic was directed across the switching fabric. The results of the following performance tests are included here:

 RFC 2544 Layer 2 throughput and latency operating in store-and-forward mode

 RFC 2889 Layer 2 and 3 throughput and latency operating in both store-and forward mode and cut-through mode

 RFC 3393 Layer 2 jitter (latency variance) operating in store-and-forward mode

Among the key test results:

 In store-and-forward mode, the Z9500 transmits Layer 2 packets of all sizes (64 to 9,216 bytes) at full line-rate on all 132 x 40GE ports, with zero loss and with low latency.

 Operating in both store-and-forward and cut-through modes, the Z9500 readily transmits Layer 3 packets of all sizes (70 to 9,216 bytes) at full line-rate with zero loss and with low latency.

 The Z9500 exhibits impressively low Layer 2 jitter (latency variance) while operating in store-and-forward mode.

 The switch consumes a comparatively respectful 15.65 watts per 40GE port, with all 132 x 40GE ports handling a random mix of Layer 2 packet sizes, 64 to 9,216 bytes, at 100 percent full load.

 Experienced zero loss of Layer 2 minimum-size (64-byte) packets during a 15-hour test that applied traffic across the switching fabric on all 132 x 40GE ports.