Tag Archives: SFP+ DAC

Copper Cabling Choices For 10GbE

As switching standards is growing maturer and copper cabling standards catch up, the use of copper cabling for 10GbE is becoming more and more popular. Currently, there are four different copper cabling technologies for 10 Gigabit Ethernet, each with its pros and cons. Although fiber (SFP+ optics) delivers the lowest latency and feature flexibility, many IT departments still prefer to use copper cabling for switch-to-switch or switch-to-server connections.

10GBase-CX4

10GBASE-CX4 was the first 10G copper standard published by 802.3. CX4 modules use 4-lane PCS and copper cabling and have a maximum distance of 15 meters. Despite its larger size of connector, CX4 module was initially designed as a replacement for legacy Infiniband switching hardware and a lower-cost switch interface. 10GBASE-CX4 offers the advantages of low power, low cost, and low latency, but has a bigger form factor and more bulky cables than the newer SFP+ standard and a much shorter reach than fiber or 10GBASE-T.

10G SFP+ Direct Attach Cabling

10G SFP+ DAC is also known as 10GSFP+Cu, 10GBase-CR, or 10GBase-CX1, SFP+, or 10GbE Cu SFP cable. SFP+ Direct Attached Cables feature rugged twinaxial cables that connect directly into a low-profile small form-factor pluggable plus (SFP+) diecast connector housing. SFP+ Direct Attach has a fixed-length cable, typically 3, 5 or 7m in length, and like 10GBASE-CX4, feature 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+.

10g sfp+ dac

10GBASE-T

According to wikipedia, 10GBASE-T is a standard released in 2006 to provide 10 Gbit/s connections over unshielded or shielded twisted pair cables, over distances up to 100 meters. 10GBASE-T SFP+ copper transceiver module uses standard RJ-45 connectors that are already widely used with Ethernet. 10GBASE-T cable infrastructure can also be used for 1000BASE-T allowing a transition from 1000BASE-T using auto negotiation to select which speed to use. 10GBASE-T is available from several manufacturers like Mikrotik, HPE and FS.COM with power consumption of 3-4 W per port with current generation PHY’s (2012) and promise even better power management in the future.

Backplane

Backplane Ethernet, also known as 802.3ap, is used in backplane applications such as blade servers and modular routers/switches with upgradable line cards. 802.3ap implementations are required to operate in an environment comprising up to 1 meter (39 in) of copper printed circuit board with two connectors. There are two port types for 10 Gbit/s Backplane specs, (10GBASE-KX4 and 10GBASE-KR). New backplane designs use 10GBASE-KR rather than 10GBASE-KX4.

Conclusion

The growth in the number of 10Gb Ethernet networks and the improved efficiency in the physical layer components, have allowed 10Gb Ethernet deployments to have a much broader footprint. 10GbE optics like 10GBASE-T copper SFP+ transceiver module begin to take up a foothold in 10G network deployment. More importantly, 10GBase-T provides a cost-effective method for migrating from your current network to 10G Ethernet by utilizing your existing RJ-45 copper short connections. For 10GbE network components, you get them either on Amazon, Mikrotik, HP or FS.COM.

10G Network Access Options: Which One Benefits You Most?

Since the IEEE standard for 10 Gigabit Ethernet (10GbE) has been ratified several years ago, 10GbE is popular in corporate backbones, data centers and server rooms of large enterprises. As time goes by, 10GbE technology is booming. This post mainly focuses on two prevalent 10G network access connectivity options and what benefits operators can get from them.

10G Network Access Connectivity Options

With improvements in utilization and virtualized assets, network servers now increased input and output demand. In order to meet this growing demand, there are two common connecting solutions in 10GbE networks: SFP+ direct attach cable (DAC) and 10Gbase-T SFP+ transceiver modules.

SFP+ DAC

DACs have been put into practice since about 2007. SFP+ DAC is a copper interconnect using a passive twinax cable assembly that connects directly into an SFP+ housing. By using inexpensive copper cable with SFP+ plugs integrated at both ends, SFP+ DAC offers 10 Gigabit Ethernet connectivity between devices with SFP+ interfaces. Besides, SFP+ DAC has passive and active conversions. Passive version suits connections up to 7m and active version fixes connectivity up to 15m. Due to the distance limitation, the target application of SFP+ DAC is interconnection of top-of-rack switches and storage devices in a rack. In a word, SFP+ DAC is a low cost solution for shorter distances.

10g-sfp-cabes

10Gbase-T SFP+ Transceiver Modules

10GBASE-T SFP+ transceiver module is well known as SFP+ form-factor, utilizing Cat 6a UTP (Unshielded Twisted Paired) structured cabling for network connectivity. In addition, this type of transceiver supports links up to 30m on Cat6 or Cat7 cable, which is longer than SFP+ DACs. It’s the first SFP+ transceiver that offers 10Gb/s communication over this type of media. And this SFP+ transceiver module is compatible with SFF-8432 and plugs into any standard SFP+ interface. Its standard RJ45 socket fits connections to any Cat 6a cabling.

10gbase-t-sfp-plus-transceiver-modules

SFP+ DAC Vs. 10Gbase-T SFP+, Which Option Is Better?

Deploying a smooth connection, a number of factors should be taken into account. As the price and power consumption continues to grow, choosing the most practical solution becomes important. Then, SFP+ DAC Vs. 10Gbase-T SFP+, which one is superior?

First, let’s make clear what benefits the two options can offer.

Options Advantages Disadvantages
SFP+ DAC Low overall cost; low power consumption; low latency; offer “pay-as-you-grow” flexibility Short transmission distance; need more cost when installed in Cat 6a cable
10Gbase-T SFP+ Transceiver Longer reach; familiar RJ45 connectors and Cat 5/6/7 cables; Interoperable with any SFP+ cage and connector system Relatively high latency which may cause delays in CPU and application works

We have a simple comparison between SFP+ DAC and 10Gbase-T SFP+ transceiver modules. From the chart, we can see each comes with its own distinct advantages and disadvantages.

With lower power consumption and lower latency, SFP+ DAC is a great choice for large high-speed computing applications where latency is an important factor. But SFP+ DACs offer less than a 10m distance. If the transmission distance increases, so does the cost. What’s more, SFP+ DACs are factory terminated and must be purchased in pre-determined lengths, which add overhead to cable management inventory. 10Gbase-T SFP+ transceiver modules have a good interoperability because of its RJ45 interface, which means this transceiver offers more design flexibility using structured cabling approach for longer distances up to 100 meters.

Summary

SFP+ DAC and 10Gbase-T SFP+ transceiver modules play an important role in 10GbE network systems. When there is a need to choose between SFP+ DAC and 10Gbase-T SFP+ transceiver, carefully consider your practical needs. If power consumption and latency are critical for you, SFP+ DAC may be suitable for you. And if flexibility and long reach are more important, then 10Gbase-T SFP+ transceiver module is a better solution.

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.