Three Media Options for 10GbE in Data Centers

With the added network infrastructure complexity, power demands, and cost considerations, 10 Gigabit Ethernet (GbE) comes to network administrators’ thinking point. While 1GbE connection is able to handle the bandwidth requirements of a single traffic type, 10GbE has been preferred as the ideal solution by customers to meet current and future input/output (I/O) demands. Delivering more bandwidth, 10GbE simplifies the network infrastructure at the same time by consolidating multiple gigabit ports into a single 10gigabit connection.

Generally speaking, there are three media options for 10GbE: 10GBASE-CX4, SFP+, and 10GBASE-T. Each option has its own virtual point and downside in terms of cost, power consumption and distance reach. This paper analyzes these three options respectively, helping you understanding the pros and cons of current 10GbE media options.

10GBASE-CX4

10GBASE-CX4 was the first 10G copper standard published by 802.3 (as 802.3ak-2004), an early favorite standard for 10GbE deployments. Using the XAUI 4-lane PCS (Clause 48) and copper cabling similar to that used by InfiniBand technology, 10GBASE-CX4 is able to reach 15 meters. Practically, this option is limited by its heavy weight and expensive cables. In addition, the size of the CX4 connector prohibited higher switch densities required for large scale deployment. Larger diameter cables are purchased in fixed lengths, causing problems in managing cable slack. What’s more, the space isn’t sufficient to handle the larger cables.

10GBASE SFP+

SFP+ fiber optic cables and SFP+ direct attach cables (DACs) are all better solution than CX4.

10GBASE SFP+ Fiber Optic Cables

10GBASE-SR, 10GBASE-LR, 10GBASE-LRM are all specified to work through fiber optic cables, such as JD094B (shown below). This HP 10GBASE-LR SFP+ transceivers takes fiber as its transmission medium with distance up to 10km. Really, great for latency and distance, but fibers are expensive. Although they offer low power consumption, the project of laying fiber networks in data centers is limited due to the cost of the electronics largely. The fiber electronics can be four to five times more expensive than their copper counterparts, meaning that ongoing active maintenance, typically based on original equipment purchase price, is also more expensive.

JD094B, HP 10GBASE-LR SFP+ transceiver

10GBASE SFP+ DAC

DAC can be classified in to direct attach copper cable and active optic cable (AOC). On the one hand, SFP+ DAC is a lower cost option alternative to fiber, with its distance reaching flexible in 1m (eg. SFP-10G-AOC1M), 2m, 3m, 5m, 7m and so on. On the other, SFP+ DAC is not backward-compatible with existing 1GbE switches. Besides, this solution requires the purchase of an adapter card and requires a new top of rack (ToR) switch topology. And the cables are much more expensive than structured copper channels, and cannot be field terminated. All these factors make SFP+ DAC less popular the 10GBASE-T which will be discussed soon.SFP-10G-AOC1M, for short reach

10GBASE-T

10GBASE-T, or IEEE 802.3an-2006, is a standard released in 2006 to provide 10Gbit/s connections over unshielded or shielded twisted pair cables with distances up to 100metres (330 ft). Due to additional encoding overhead, 10GBASE-T has a slightly higher latency in comparison to most other 10GBASE standards. What’s more, 10GBASE-T offers the most flexibility, the lowest cost media. And because of its backward-compatibility with 1000BASE-T, 10GBASE-T can be deployed based on existing 1GbE switch infrastructures that are cabled with CAT6 and CAT6A (or above) cabling, keeping costs down while offering an easy migration path from 1GbE to 10GbE.

Conclusion

The deployment of 10GbE infrastructure should be much easier, with these media options in mind, coupled with your own such project considerations as cost, power consumption and distance reach. fiber-mart, as a professional fiber optic product supplier, offers a broad selection of fiber and copper cables, including SFP-10G-AOC1M mentioned above. For more information about 10GbE media options, you can visit fiber-mart.