Tag Archives: DAC

The Evolution Path of BASE-T

With the requirements laid on data center increasing rapidly, the ability to flexibly adapt to future demands is tremendously crucial for data center managers. Often this can be achieved by deploying higher bandwidth solutions in a part of the data center, provided that these systems are backwards compatible with existing infrastructure or it may be a cost-consuming method. BASE-T technology featured by its low cost, availability and flexibility is largely favored by data center designers. This article illustrates the migration of BASE-T technology so that people can future proof their data center tomorrow.

Why BASE-T Is so Popular?
To be short, three main advantages will be concluded in the following part.
1. Least cost access layer alternative when compared to other interconnect technologies

  • Optical (e.g. SR, LR)
  • Direct-Attached

2.Structured topology

  • Common physical interface (RJ45)
  • Flexibility and longevity
  • Optimized for small to medium-sized data centers (< 20K square feet)

3. Supports auto-negotiation and Power-Over-Ethernet

  • Simple plug and play installation
  • Ubiquitous RJ45 interface simplifies 10GBASE-T to 40GBASE-T upgrade path

1000BASE-T—Gigabit Ethernet Over 4-pair Cat 5 Cabling
1000BASE-T (ratified in 1999) is a Gigabit Ethernet standard over copper wiring at the speed of 1000 Mbps. Each 1000BASE-T network segment can support a maximum length of 100 meters, and uses Category 5 cable or better (including Cat 5e and Cat 6). 1000BASE-T also uses a symbol rate of 125 Mbaud and all four pairs for the link and a more sophisticated five-level coding scheme. The 1000BASE-T SFP operates on standard Category 5 unshielded twisted-pair copper cabling of link lengths up to 100 m.

Realizing 10BASE-T
Upgraded from 1000BASE-T, 10GBASE-T (certificated in 2006) offers the most flexibility, the lowest cost media, and is backward-compatible with existing 1 GbE networks. 10GBASE-T connected with Cat 6 and Cat 6A (or above) cabling supports a length up to 100 meters that gives IT managers a far greater level of flexibility in connecting devices in the data center. 10GBASE-T and Category 6A cabling costs less than using either optical fiber or SFP+ direct attach copper (DAC) options that have been widely deployed to date center for 10 Gb/s. For example, EX-SFP-10GE-DAC-1M can only support a link length of 1m that largely limits its application. Figure 1 presents a comparison between 1000GBASE-T and 10GBASE-T.

comparison between two BASE-T technology

Road to 40GBASE-T in Data Center Networks
If there is a 10GBASE-T for switch-to-server and switch-to-switch connectivity, there will be a 40GBASE-T over twisted pair cabling for the 40G data center deployment according to the IEEE. Twisted pair cabling with the RJ-45 connector has always been the first choice for IT professionals, based on its low cost and ease of use. Unlike fiber or twinax solutions, twisted pair cabling can automatically switch to different data rates, such as from 100MbE to 10GbE. Therefore migration to 40GBASE-T does not require a upgrade of all the equipment of the data center, which will reduce of the overall expenditure of the data center.

The advantages of 40GBASE-T are clear, but the path from initial ratification to commercial availability is not always smooth. There still a few months off for 40GBASE-T standardization, here comes some good news, as well as some considerations.

40GBASE-T is specified with transmission performance up to 2 GHz (four times the bandwidth of Category 6A) with a lot more stringent alien crosstalk requirements. Since initial 40GBASE-T applications would be limited to data centers, the traditional twisted pair Ethernet 100m link length is not essential. Additionally, Industry players helping in the development of an industry standard for 40GBASE-T have to ensure that it could be supported and rolled out cost-effectively. The new standard will minimize the time it will take to develop new electronics for switches and servers that can support 40GBASE-T connectivity, by building on the work already completed to support 10GbE connections. The standard will also support the ubiquitous RJ-45 connector. Sooner or later, 40GBASE-T will be upon us. Nowadays 40GBASE-LR4, 40GBASE-SR and 40G QSFP+ cables are there to help with the deployment of 40G connectivity. Take JG330A as an example, it is QSFP+ to 4SFP+ Passive Copper Cable available for short reach application. Figure 2 shows a data center twisted-pair migration roadmap.

Data Center Twisted-Pair Migration Roadmap

Summary
BASE-T technology (1000BASE-T, 10GBASE-T or 40GBASE-T) always retains the traditional advantages—low cost, easy to deploy and auto-negotiation for plug and play and backwards compatibility. 1000BASE-T and 10GBASE-T have already brought benefits to people. But no one can foresee that 40GBASE-T will be used in the future but future-proof planning of the cabling is important, given the long life of the cabling systems. Fiberstore provides a full range of BASE-T products including 1000BASE-T SFP, 1000BASE-T media converter, 1000BASE-T GBIC transceiver, etc. And 40GBASE-T devices will be coming soon. If you have any request of our products, please send your inquiry to us.

 

Introduction to 10G SFP+ Twinax Cabling

Driven by the never-ending requirement for faster data-rate transmission, Ethernet technology has continually evolved from 1GbE to 10GbE and eventually to 100GbE. This demand for faster application speed has also spurred technological evolution on data carrying techniques. Consequently, fiber and copper transmission standards has been progressed, providing greater bandwidth for transporting data over Ethernet architectures with reduced cost and complexity. In today’s article, some detailed information will be provided on 10G SFP+ twinax cabling.

Why Implementing 10G SFP+ Twinax Cabling?
Many research companies forecast that 2016 will be the year of 100G. So why implementing 10G twinax cabling here? There are several reasons which will help you sort this out. Regardless of cost, most LAN infrastructures employ a mixture of copper and fiber premises wiring. 10GbE bandwidth are generally sufficient to support the transfer and streaming of large data, video and audio files. Thus there are no demands for greater network performance or application bandwidth. What’s more, costs associated with re-cabling a network can be exorbitant and organizations should take precautions to ensure their cabling systems can last well into the future. 10GbE twinax cabling provides the best assurance for being able to support forthcoming technologies and delivers utmost investment protection.

What Is 10G SFP+ Direct Attach Twinax Cable?
SFP+ Direct Attach Cable (DAC) is a copper 10G Ethernet cable which comes in either an active or passive twinax cable. The difference between them is that an active twinax cable has active electronic components in the SFP+ housing to improve the signal quality while a passive twinax cable is just a straight “wire” and contains few components. As such, they support different transmission distance. SFP+ DAC cables use SFP+ MSA and copper “twinaxial” cable with SFP+ connectors on both sides providing 10 Gigabit Ethernet connectivity between devices with SFP+ interfaces, which is expected to be the optimum solution for 10G Ethernet reaches up to 10 m.

Passive SFP+ Twinax Cable Assemblies
The passive SFP+ twinax cable is designed to support connections for 10 Gigabit Ethernet or Gigabit Ethernet switches with 10 Gigabit Ethernet uplink. Passive SFP+ cables, as noted before, have no electrical components and typical cover a distance of 1m, 3m, and 5m. For example, compatible Cisco SFP+ cables from Fiberstore like SFP-H10GB-CU3M, SFP-H10GB-CU1M, and MA-CBL-TA-1M, are programmed specifically to work with Cisco equipment. When these cables are plugged into Cisco equipment, they will not trigger the warning message that a non-Cisco transceiver has been detected. Figure 1 shows compatible Cisco SFP-H10GB-CU3M SFP+ to SFP+ passive copper cable with SFP+ connectors.

SFP+ Passive Copper Cable with SFP+ connectors

Active SFP+ Cable Assemblies
Active SFP+ twinax cables, compared with passive SFP+ cables can support longer transmission distance of 7m and 10m or up to 15m (distance may vary from vendors to vendors). For designs that only support SR and LR applications, active direct attach copper cable assemblies provide functions such as transmit disable and receiver loss of signal in addition to signal amplification, which makes it ideal for highly cost-effective networking connectivity between switches and servers. Figure 2 shows an active copper SFP+ DAC cable with SFP+ connectors.

SFP+ Active Copper Cable with SFP+ connectors

From these two pictures, we can see that there is no visual difference between active and passive SFP+ twinax cables. So, people should read the product specifications carefully before purchasing twinax cables.

Summary
SFP+ twinax cables offer a cost-effective way to interconnect 10G Ethernet devices within racks and across adjacent racks. These cables are usually accommodated into the SFP+ transceiver housing of a switch or server. Fiberstore SFP+ twinax DAC cables provide robust connections for leading edge 10GbE systems. We provide a full range of SFP+ DAC cables including SFP-H10GB-CU3M, SFP-H10GB-CU1M, EX-SFP-10GE-DAC-1M, JD097C, JD095C, etc. These SFP+ twinax cables are fully compatible with major brand. For more detailed information, please visit www.fs.com or contact us over sales@fs.com.

Make Your Network Ready for 40GbE to the Server

In today’s server networks, 40GbE has become commonplace and has gradually taken over multiple 10GbE links to each server. Installation of 40GbE devices in the field will be a requirement for customer service and reduced operating costs. So are you ready for embracing 40GbE era? But how should the network prepare for delivering 40GbE to servers?

The core of the 40GbE networking, just like the 1GbE or 10GbE networks, is a pair of transceiver modules connected by optical patch cables. Thus the issue here is to pick the right 40GbE optical devices for your network server. 40G optical transceiver modules has several form factors—CFP (C form-factor pluggable) transceiver, CXP transceiver form factor and QSFP/QSFP+ (quad small-form-factor pluggable) transceiver. 40G QSFP modules recently gain more popularity on the market as a result of its small size and high performance. Thus selecting 40G QSFP modules is a cost-effective solution for your 40GbE network server.

A Quick Overview of QSFP Transceiver Modules
QSFP is a compact, hot-pluggable transceiver used to plug into network servers, interface cards or switches. It provides four transmit and four receive lanes to support 40GbE applications for multi-mode and single-mode fiber and copper today. A variety of QSFP transceivers are available on the market, such as QSFP-40G-CSR4, QSFP-40G-PLR4, 40GBASE-PLRL4, QSFP-40G-SR4, QSFP-40G-LR4, etc. Take QSFP-40G-ER4 (see in Figure 1) as an example, it is the compatible Cisco QSFP-40G-ER4 QSFP modules that extend the reach of the IEEE 40GBASE-ER4 interface to 40km on single-mode fiber.

QSFP-40G-ER4

DAC and AOC Cabling
The standards for 40GbE have been around for more than 2 years, and a number of routers, switches, and network cards have already operated at this speed. 40GbE cabling is also an important segment of upgrading your network. As we know that the most cost-effective cabling for both 10GbE and 40GbE is the direct attached cable (DAC) type based on twinaxial cabling. Such cables are based on copper and have transceivers directly connected to each end of the cable. 40GbE uses the slightly larger QSFP transceivers, which internally are made up of four 10Gbit/s lanes. DAC cables exist in lengths up to 10 meters, but the price increases substantially when the cables get longer than 3 to 5 meters. When longer runs of 10GbE or 40GbE than 10 meters are needed, fiber cabling and separate transceivers are the only option. Active optical cables can achieve high data center over long reaches. In addition to achieving longer reach, the lower weight and tighter bend radius of AOCs enable simpler cable management and the thinner cables allows better airflow for cooling. But the cost of each transceiver is usually several times that of one DAC cable. Constraints like that are important to take into account when designing a data center network. Figure 2 shows a compatible Cisco QSFP-4SFP10G-CU3M QSFP+ to 4SFP+ Passive Breakout Copper Cable.

QSFP-4SFP10G-CU3M

Prospect

  • 40 GbE will arrive for Top of Rack solutions in 2016.
  • Switches in the campus backbone and aggregation layers should be ready for replacement/upgrading in 2016 to support 40GbE.
  • Do not install any cabling in your data center or campus backbone. 40GbE uses 8 fiber cores for multi-mode and 1 pair for single mode. The cable will be OM4 although OM3 will have shorter distances. Provision the least amount of cable until new cabling solutions arrive.
  • Spending money on expensive 10GbE switches will be wasted as they are likely to be replaced in 2016 with 40GbE. Most server people are already deploying/asking for 4x10GbE per chassis and it probably be cheaper to use a 40GbE QSPF than four 10G SFP modules in two to three years time.

Summary
Believe it or not, the 40 Gigabit Ethernet era is already upon us. Therefore it is essential to make yourself well prepared for the incoming big data age. Over these years, Fiberstore has built a good reputation for uncompromising product quality, reliability and technical innovation. We offer a broadest portfolio of optical devices on the market today. For more detailed information, please contact us directly.