So you've selected the server, storage and networking technologies to setup your data center. Now how do you connect it all together? There's a little more to the answer than just “with cables.”
Let's look at the most common methods of connecting servers and storage to switches using 10Gb Ethernet capable network adapters and cables.
The three methods I’ll compare are 10Gb SFP+ optics, 10Gb using TwinAx or direct attach copper cables, and 10GBASE-T. All three are technologies that allow you to move data between servers, storage and network devices at high-speeds (10Gb speeds now, but 40Gb and 100Gb coming soon).
I won’t dive into the deep technical nuances of the hardware (don’t hesitate to contact us for expert technical help though!), but rather explain when you should choose one connection method over another, and what parts you’ll need to order to ensure it’s all functional.
10Gb SFP+ Optics
This requires two things on each device: a 10Gb SFP+ network adapter card and pluggable SFP+ transceivers that fit inside the SFP+ ports.
SFP+ transceivers are also sometimes referred to as mini-GBICs.
Once these are in place on both devices (for instance a server network adapter and a switch), you can plug an optical fiber cable into the transceiver on both sides.
Pros: This connectivity method supports fiber cables that are really long, allowing you to connect a server at one end of a data center to a switch several racks away or even at the other end.
Cons: Pluggable transceiver parts are quite expensive.
|SFP+ GBIC that goes into the network adapter port|
|SFP+ 10Gb network adapter|
|The optical fiber cable that plugs into the GBIC|
10Gb Using TwinAx or Other Direct Attach Copper (DAC) Cables
This approach also requires a 10Gb SFP+ network adapter card to be installed in each device, however this solution does not require pluggable SFP+ transceivers to insert in to each port on the adapters.
DAC cables are a type of Twinaxial (twinaxial) cabling, you'll often hear the terms used interchangeably.
Pros: The cables that you use to connect the adapters between the devices have built-in transceivers that slot right into the adapter’s SFP+ ports so you are saving the cost of expensive pluggable transceiver parts.
Unlike 10Gb SFP+ optics that send optical signals over the fiber cable, these cables carry the signal over copper wires. Copper is less expensive than fiber.
Cons: The cost increases significantly when the cable needs to be longer than five meters, so this option is best for devices that are in the same or adjacent racks.
|SFP+ 10Gb network adapter|
DAC that has the SFP+ transceivers built in.
This option probably looks familiar – like the RJ-45 ports and cabling you use to connect your laptop to a normal network jack. The difference is that you need specialized network adapters with ports that support faster 10Gb throughput, and CAT6 or CAT7 cables versus CAT5 cables.
CAT6/CAT7 cables have more individual copper wires, twisted tighter, with better shielding to prevent outside signal interference. They cost more than CAT5 but ensure better signal communication, which is a requirement to speed up to 10Gb.
Pros: Companies are moving towards this option more and more, because they can use standard cabling for both 1Gb and 10Gb without the other more expensive options mentioned above.
Cons: None really. The only reason it isn’t even more popular, is that many data centers have switches that only support SFP+, which means they have to select a 10Gb SFP+ cabling method to connect their server and storage arrays switches.
|10GBASE-T network adapter
(with the familiar RJ-45 ports)
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