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Top of Rack (TOR) Vs. Centralized Data Center Switching

switch-analysisDuring a recent data center design we reviewed the next generation of LAN switching in data centers. We found one key change in the next generation data center switches from Cisco, HP, Juniper, Arista, Huawei. RJ45’s  seem to be coming back. For the past few years data center designs were exclusively Top of Rack (TOR) designs with twin ax or fiber SFP cables from LAN switches to servers or chassis.


  1. Cisco’s competition is delivering 10G via RJ45’s at lower cost
  2. Install base, many customers have Category 6 or 6A. Category 6 supporting distances of 55M, category 6A to 100M. Most of the switch to server connections are within 50M.
  3. Most servers and chassis manufactures have RJ45, 10G interfaces

We have proven that LAN switches go under utilized but this was accepted because it was the only option to deliver  10G to servers and storage. TOR designs are not going away by any means especially with a spine/leaf designs that can deliver 40 and 100G to leaf switches with very low latency. The question will be how long will be before (2) to (4) 10G connections is no longer adequate to servers. One key expectation to this is the Cisco UCS platform as it does not leverage traditional TOR switches.

This is good news for some customers, as it may extend the life of the current designs.

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