10GbE Offers Various Connectivity Options to Data Centers

Since it started out as a popular local-area network (LAN) technology, Ethernet has developed unceasingly into a networking method for metro-area networks (MANs). While Fibre Channel and InfiniBand have their places, Ethernet still dominates among data centers that interconnect hundreds and even thousands of servers, routers, and switches. With millions of ports, Ethernet proves itself as the most well-known networking technology worldwide, serving as the networking protocol in data centers. This article discusses the numerous connectivity options offered by 10GbE to data centers.

10GbE Standards

At initial stages, 1GbE technology had great use in LANs, MANs, and data centers. Lately, the rise of cloud computing, coupled with the increased use of unified data/storage connectivity and server virtualization by enterprise data centers, has led to a great desire for ever-higher data-rate links. Then links operating at 10 Gbits/s were made possible.

Just like its prior generations, 10GbE rapidly dominated in the computing networks because of its ubiquity, the ready and familiar management tools, along with the compelling cost structure. To deploy 10GbE links can take on many forms, ranging from optical modules to copper transceivers which are connected to Cat6A unshielded twisted-pair cable. In 2002, the IEEE created several standards for 10GbE connectivity (802.3ae), including

• 10GBASE-SR: operates over multi-mode fiber (MMF) using optical modules with 850nm lasers

• 10GBASE-LR: operates over single-mode fiber (SMF) using optical modules with 1310nm lasers

• 10GBASE-LRM: operates over MMF using optical modules with 1310nm lasers

• 10GBASE-T: operates over Cat6 or Cat6A twisted-pair copper cabling with distance up to 100m

• 10GBASE-KX4: operates over four copper backplane lanes with distance up to 1m

• 10GBASE-KR: operates over a single backplane lane with distance up to 1m

Besides, a non-IEEE standard approach called SFP+ Direct Attach Cable (DAC) has gained in popularity. It uses a passive twin-ax cable assembly that connects directly into an SFP+ module housing. Take Cisco SFP-H10GB-CU1M for example, this product is the 10G SFP+ direct attach twinax cable assembly for 1m length.

10GbE Optical Modules

Optical transceivers are housed and available in modules specified by multi-source agreements (MSAs) which are created by module manufacturers and equipment OEMs. Over the years, the form factor had evolved from XENPAK to X2 to GBIC to SFP to XFP and to SFP+ modules.

SFP+ optical modules designed for 10GbE applications are full duplex transceivers. In data centers, 10GBASE-SR (short range) modules have emerged as the most popular variant of the optical options. This 10GBASE-SR compliant transceiver uses 850nm lasers over LC fiber cable, incorporating a vertical-cavity surface-emitting laser (VCSEL), which is lower in both cost and power than side-emitting DFB lasers needed for SMF. Over older FDDI-grade 62.5µm MMF, 10GBASE-SR maximum link length is 26m;over 62.5µm OM1 fiber 33m;over 50µm OM2 fiber, 82m; over OM3 fiber, 300m; and over OM4 fiber, 400m.

10GbE Copper Solutions

For 10GbE applications, copper-based solutions generally fall into two categories: distances appropriate to backplanes within a box, and distances associated with connections between boxes.

Both 10GBASE-KX4 and 10GBASE-KR are intended for inter-box backplane connections with distances up to 1m. The major difference between the two is that KX4 operates over four copper lanes, while KR is a serial 10-Gbit/s link operating over one lane.

Another copper solution is the SFP+ DAC link. This kind of cable assembly is ordered in pre-specified lengths and come with attached SFP+ module form-factor connectors.

The other copper -based connectivity option is 10GBase-T, also known as IEEE 802.3an. With 10GBASE-T, 10-Gbit/s communications occur over unshielded twisted-pair cabling. It’s the fourth generation of so-called GBASE-T technologies, which all use RJ45 connectors and unshielded twisted-pair cabling to provide 10- and 100-Mbit/s, and 1- and 10-Gbit/s data transmission. A 10GBASE-T transceiver uses full-duplex transmission with echo cancellation on each of the four twisted pairs available in standard Ethernet cables, transmitting an effective 2.5Gbits/s on each pair. Category 6 or category 6A cabling is typically used with 10GBase-T. Cat6 is specified for distances up to 55meter, whereas Cat6A is specified for up to 100m.

Comparing 10GbE Connectivity Options

10GBASE-T connectivity, backward-compatible with the existing 1GbE cabling infrastructure, is the most flexible, economical, and user-friendly 10G Ethernet10GbE connectivity option available. Its benefits include the ability to interoperate with legacy slower technologies, the use of ubiquitous and inexpensive cabling and connectors, the flexibility of full structured wiring reach, the ease of Cat6A cabling deployment, and power-saving features. As a result, 10GBASE-T is ideally suited for the rapidly expanding needs of today’s data centers.

Conclusion

10GbE does well in the inter-switch and storage side, creating a convergence between networks designed primarily for voice, and the new data centric networks. Fiberstore, as a professional fiber optic product supplier, supplies various kinds of 10GbE transceivers fully compatible with major brands at really low prices, as well as detailed SFP+ DAC cabling solutions. Here, you can find what you want quickly for your 10GbE applications.