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Time to replace RJ-45 connectors in the data center?

Ubiquitous RJ-45 connectors reign supreme even in the wake of newer data center technologies. USB 3.1 cables are out there; can they be the next big thing?

Is it time for USB-C to replace RJ-45 connectors in the data center? I know, I know. I can hear you saying it: "What is this blasphemy? No consumer abomination shall soil my racks. A heretic! Burn him at the stake. Yea, verily."

True, universal serial bus (USB) is device-to-host and no two self-respecting routers or switches should ever be anything other than peer-to-peer. USB is also a low-level standard, not tuned for Ethernet packets. And while there have been dozens of heir-apparent replacements for our trusty copper Ethernet, none have ever more than momentarily taken the lead. But perhaps, especially in compute-intensive data centers, we might be ready for a change.

Five-cent plastic tenacity

Other than power, is there any connection in IT with greater longevity and ubiquity than RJ-45? Certainly, serial and a few others -- like the humble D-Sub (video graphics array) connector -- will outlast everything other than Windows XP, but they mostly just gather dust. With telco beginnings, the 8-position 8-contact (8P8C) connector has reigned supreme. Does anyone really miss extraneous Fibre channel SFP connectors? No. So, Fibre Channel over Ethernet (FCoE) is assimilating yet another would-be successor. Certainly, there are plenty of links where fiber is the only reasonable solution, usually based on length, but for most connections, the familiar click of a latching tab is desired.

There's a simple reason RJ-45 cables succeed: We like them, a lot.

There's a simple reason RJ-45 cables succeed: We like them, a lot. Every time I think we've hit the wall, sharp engineers motivated by what I can only assume is outright refusal to let the familiar Ethernet standard die, take it further. As of this writing, 40GBASE-T over CAT 8 is next up for enterprise, and with Bell Labs showing 10 Gbps speeds over crummy two-pair phone wire, who knows where four-pair CAT.next will take us. As technologists, we just seem to love our venerable, wonderfully inexpensive RJ-45 connectors plug.

On the other hand, Ethernet (the protocol), doesn't have much conduit loyalty. Its promiscuity extends all the way to consumer connectivity like HDMI (and HDMI Ethernet Channel), and with a little frame encapsulation, USB-C (also known as USB 3.1), which is produced by the billions, would be the world's cheapest 10 gig data cable bar none. Better, you might eliminate power and KVM cables.

A USB 3.1 thought experiment you may want to try

Imagine a full rack of commodity servers using Facebook, OpenCompute or another open standard architecture. Each has storage, , CPU, Ethernet connector and power cable. Most also have either an on-board battery to provide some short outage uninterruptable power supply or a full power supply. That's a lot of power components, connectors and cables, especially when you multiply by the number of PC boards in the rack. So, what if you USB 3.1 cables?

, 5 amps (100 watts/20 volts) is a lot of power for a data cable. It's plenty to run a commodity PC, especially one with flash storage (Ethernet PoE+ is only one-fourth of that). Second, while USB signaling is not as efficient as multipair Ethernet, there are a number of existing solutions for passing 802.3 frames over USB. For example, the Linux USB-eth module makes USB look just like Ethernet to the OS -- IP, MAC and all. USB has also been doing KVM since the beginning, so that's one other converged protocol in a single cable. It's even proven good enough to supplant SATAe.

The missing component is the top-of-rack switch, and here's where commoditization really helps out. Though a gross oversimplification, the guts of that box would be 64-port Broadcom Trident silicon, plus a 6,400-watt power supply with 10 Gb or 40 Gb fiber uplinks. Communication and power infrastructure would be converged into a single device. With a little frame encapsulation, silicon racks would then contain only two unit types connected by a single flavor of very inexpensive USB 3.1 cabling. Imagine how hugely simplified monitoring and management of a single network/power distribution unit device and a swarm of PCs would be with only one plug.

Perhaps one day our trusty and dependable Ethernet cabling -- armed with RJ-45 connectors -- will disappear. Do I really believe USB 3.1 will replace data center cabling? Of course not. I love my LEGO-like, clicking crystal connectors too much to consider that, and I hope PoE goes more than 25 watts. But sooner or later, convergence of power and data may come to the data center, and that won't be a bad thing.

In the meantime, my phone's dead. Does anyone have a Lightning cable?

About the author:
Patrick Hubbard is a head geek and senior technical product marketing manager at SolarWinds. With 20 years of technical expertise and IT customer perspective, his networking management experience includes work with campus, data center, storage networks, VoIP and virtualization, with a focus on application and service delivery in both Fortune 500 companies and startups in high tech, transportation, financial services and telecom industries. He can be reached at [email protected]

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This was last published in April 2015

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