10 Gigabit Ethernet, known as IEEE 802, was first ratified in 2002. With the increasing bandwidth requirements, numbers of large enterprises have started deploying 10GbE in their corporate backbones, data centers and server rooms to support high-bandwidth mission-critical applications. Over the years, improvements in 10GbE technology is extending its reach beyond enterprise data centers to broader market. However, do you really get to know what 10 Gigabit Ethernet means?
10 Gigabit Ethernet (10GbE) is a telecommunications technology that transmits data packets over Ethernet at a rate of 10 billion bits per second. This innovation extended the traditional and familiar use of Ethernet in the local area network (LAN) to a much wider field of network application, including high-speed storage area networks (SAN), wide area networks (WAN) and metropolitan area networks (MAN). 10Gb Ethernet is an important and cost-effective technology for network managers that can easily be deployed within existing networks to meet their high-speed and low-latency requirements.
The standards for 10G Ethernet were first defined by the IEEE 802.3ae in 2002 which include the physical layer specifications (PHY), types of physical media-dependent interfaces (PMDs), supported media and reaches. All the 10GbE standards are shown in the following table:
|10GBASE-SR/SW||850nm||Serial||400m||MMF||XENPAK X2 XFP SFP+|
|10GBASE-LR/LW||1310nm||Serial||10km||SMF||XENPAK X2 XFP SFP+|
|10GBASE-ER/EW||1550nm||Serial||40km||SMF||XENPAK X2 XFP SFP+|
|10GBASE-LRM||1310nm||Serial||220m||MMF||XENPAK X2 XFP SFP+|
|10GBASE-ZR/ZW||1550nm||Serial||80km||SMF||XENPAK X2 XFP SFP+|
|10GBASE-CX4||NA||4 Lanes||15m||Twinax Copper||XENPAK X2 XFP|
|10GBASE-KX4||NA||4 Lanes||1m||Improved FR-4||NA|
|10GBASE-CR||NA||Twisted Pair||15m||Twinax cable||SFP+|
|10GBASE-PR||1270nm/1577nm||Passive Optical Network||20km||SMF||10G EPON|
Here is the introduction to some commonly used 10GbE standards:
10GBASE-SR is a port type for multimode fiber and uses 850nm lasers. The letter “S” stands for short reach, thus the standard is designed to be deployed in a short distance. It has a data transmission rate of up to 10.3125 Gbps and can be used over multiple cabling options. But the transmission distance may differ as the fiber cable changes. For instance, when used over OM3 fiber, the 10GBASE-SR SFP module can achieve link length up to 300 meters, as opposed to 400 meters when applied over OM4 fiber.
10GBASE-LR is a port type for single mode fiber and uses 1310nm lasers. The letter “L” stands for long reach, thus this standard offers a longer distance than multimode fiber up to10km. 10G LR uses higher cost optics than SR and requires more complex alignment of the optics. There is no minimum distance for 10GBASE-LR SFP module, so it is suitable for short connections over single mode fiber as well.
10GBASE-ER is a port type for single mode fiber and uses 1550nm lasers. ER means Extended Reach, so the data rate of ER module can support distance up to 40km. It has a reach of 40km over engineered links and 30km over standard links. Due to the laser power, attenuation is required for links less than 20km long.
10GBASE-ZR is actually not an IEEE standard, but created by the vendors. ZR also stands for Extended Reach, which can transmit 10G data rate and 80km distance over single mode fiber and use 1550nm lasers. Use of ZR optics should be preceded with an optical power test of the fiber span in question to ensure a problem-free deployment.
10GBASE-LRM is developed by IEEE 802.3aq that generated the 10GBASE-LX4 standard. LRM means “Long Reach Multimode”, so it is a newer standard that provides long reach over multimode fiber with a single laser operating at 1310nm. 10GBASE-LRM reach is not quite as far as the older 10GBASE-LX4 standard. It allows distances up to 220 meters over standard multimode fiber. But LRM module has a simpler optical path because it uses a single transmitter and a receiver.
10GBASE-CR is known as 10GSFP+Cu or SFP+ direct attach. As defined in SFF-8431, it is a standard for direct attach copper cable assemblies that are effectively constructed out of a pair of XFP or SFP+ modules. It can reach 7 meters on passive copper cables and up to 15 m on active cables. Like 10GBASE-CX4, DAC cable is low-power, low-cost and low-latency with the added advantages of using less bulky cables and of having the small form factor of SFP+. So SFP+ direct attach today is tremendously popular, with more ports installed than 10GBASE-SR.
Published in 2006 by IEEE 802.3an, 10GBASE-T provides 10 Gbit/s connections over unshielded or shielded twisted pair cables to realize RJ-45 connectivity of 100 meters. It is intended to improve the performance and distance of copper cabling at a cost that is lower than fiber. By using RJ45 connectors and twisted pair cabling, 10GBASE-T allows 10Mbps, 100Mbps, 1Gbps, and 10Gbps data transmission, while being backward-compatible with prior generations. The 10GBASE-T SFP+ copper transceiver is specifically designed for high speed communication links that require 10 Gigabit Ethernet over Cat6a/Cat7 cable with a link limit of 30m. For more information about 10GBASE-T SFP+, please refer to Understanding of 10GBASE-T SFP+ Copper Transceiver Modules
With the explosive growth of cloud computing and Internet of Things (IoT), 10 Gigabit Ethernet has been the most cost-effective high-performance interconnect in the data center server network in recent years. Until recently, the Ethernet speed upgrade path was clearly defined as 10G→25G→50G→100G, is 10 Gigabit Ethernet still far in the future? So far as it goes, the deployment of 10 Gigabit Ethernet in data centers is on a growth path driven by needs for higher performance and supported by falling per-port prices for 10GbE capability.
Related Article: Choose 10GBASE-T Copper Over SFP+ for 10G EthernetRelated Article: Understanding of 10GBASE-T SFP+ Copper Transceiver Modules Related Article: FS SFP+ Optical Modules Solution
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