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How many ports are enough at the core of the data center? How does 1,024 sound?
That’s the configuration we used to assess Cisco Systems’ Nexus 9516 data center core switch. In this exclusive Clear Choice test, we assessed the Cisco data center core switch with more than 1,000 50G Ethernet ports. That makes this by far the largest 50G test, and for that matter the highest-density switch test, Network World has ever published.
As its name suggests, the Nexus 9516 accepts up to 16 N9K-X9732C-EX line cards, built around Cisco’s CloudScale ASICs. These multi-speed chips can run at 100G rates, for up to 512 ports per chassis and either 25G or 50G rates for up to 1,024 ports. We picked the 50G rate, and partnered with test and measurement vendor Spirent Communications to fully load the switch’s control and data planes.
The results were staggering. Among the key takeaways:
* Line-rate throughput for all frame sizes in tests involving IPv4, IPv6, and multicast traffic
* Support for more than 1 million IPv4 and 1 million IPv6 routes
* Support for 10,000 IP multicast groups and 10.2 million multicast routes. Both numbers are the highest levels ever achieved in multicast testing of a single system
* Power consumption between 13-22 watts per port
The recurrent theme through all tests is highly scalable performance. The Cisco switch forwarded every single frame we threw at it in every test and never dropped even one.
A Million Routes
Switch tests usually involve loading up the data plane with traffic, and we did that, but we didn’t stop there. Besides blasting the switch fabric with IPv4 unicast, IPv6 unicast, and IPv4 multicast traffic at line rate on all 1,024 50G Ethernet ports, we also fully loaded the switch’s control plane with routing state - a lot of routing state.
In the IPv4 and IPv6 unicast tests, we enabled Border Gateway Protocol (BGP) - now a common choice even inside large data centers - and advertised more than 1 million unique routes, both in IPv4 and IPv6 tests.
To get a sense of what a million routes represents, consider that the entire public Internet consists, at this writing, of around 671,000 IPv4 and 40,000 IPv6 routes. Thus, the Nexus 9516...