Have you ever read a press release containing superlatives such as “greatest” or “largest” and wondered…is that claim credible?  In today’s competitive broadband climate, it is more important than ever to deliver products that provide cost-efficiencies for the operator.  This translates to lower capital and operating costs, which in turn benefits the subscriber in the form of network and service expansions.  Where it becomes challenging is when equipment vendors advertise leadership where the actual numbers don’t add up. 

In our business, one key metric is ‘throughput per rack unit’. This is calculated as aggregate throughput in bits per second, divided by the number of rack units or RU (a rack unit is a standard unit of height equal to 4.5cm).  For example, Sandvine’s PTS 24000 has 80 gigabits per second per RU so (80 Gbps)/4RU = 20 Gbps/RU. In comparison, a platform that claimed 80 gigabits per second in 9RU or (80 Gbps)/9RU would be delivering just 8 gigabits per second per RU. 

Other meaningful metrics to explore, depending on your objective, might include the port-density angle with ‘ports per rack unit’ or a comparison of the ‘number of subscribers supported per rack unit’. Any way you slice the density question, making sense of the numbers can require cutting through some confusion as well as analysis beyond face value.