Optical community technique in knowledge facilities for cloud computing | All Tech Sir

The info heart is the final word assist platform for cloud computing. The evolution of cloud computing creates main challenges for knowledge heart community structure. Conventional electrical interconnection methods are troublesome to fulfill the wants of cloud purposes by way of bandwidth, tools prices, vitality consumption and administration complexity. Subsequently, the optical interconnect system structure characterised by low energy consumption, low value and excessive bandwidth has emerged and obtained a lot consideration.

Technical challenges {of electrical} interconnection methods

The event of cloud computing has led to a big improve in visitors within the knowledge heart. Subsequently, the usage of 10GigE switching structure within the entry layer and 40G/100GbE switching structure within the core layer has principally turn into the long run improvement pattern of knowledge heart networks. On this case, {the electrical} interconnection structure of the info heart will face the next technical challenges.


For copper cables, there’s a sure trade-off between communication bandwidth and transmission distance below rated energy, that’s, because the communication bandwidth will increase, the transmission distance of copper cables will lower. For the communication bandwidth of 10Gbps, the transmission distance of 10G copper shall be lower than 10m. To get an extended transmission distance, the ability of the transmitter should be greater than 6W/port. Subsequently, copper cable is now not the popular transmission medium because the demand for hyperlink bandwidth will increase.

Alternate capability

For the reason that transmission velocity {of electrical} alerts is proscribed by sign loss and interference between symbols on a single line, sign transmission velocity is commonly elevated by rising the bit width of the road in a chip design. Nonetheless, this technique will in the end be restricted by the chip packaging space. Subsequently, because the sign velocity will increase, the variety of ports supported by the swap chip will progressively lower. For instance, in keeping with the present expertise stage and packaging limitations, if the port velocity is 80Gbps, the utmost variety of ports supported by the swap chip based mostly on electrical integration expertise is barely 64.


Rising the bandwidth of the hyperlink will increase the transmission lack of electrical alerts in copper cables or backplane traces, so alerts should be processed with advanced pre-emphasis and error management. As well as, as a result of limitation of port density and swap capability, the swap system wants to make use of extra tools and extra advanced interconnection strategies to fulfill the wants of large-capacity switches, which will increase the tools and wiring prices of the community.

Power consumption

Power consumption has turn into one of many bottleneck components limiting the event of knowledge facilities. In response to forecasts, from 2012 to 2020, the utmost computing capability and bandwidth of high-performance computing methods will improve by 10 occasions/4 years and 20 occasions/4 years respectively, however its vitality consumption might solely improve at fee 2 occasions/4 years. fast progress.

This poses a critical problem to knowledge heart design. The community vitality consumption of the info heart is about 23% of the overall vitality consumption. By bettering connection velocity and switching capability, the share of community vitality consumption will proceed to extend.

For the reason that present vitality consumption of circuit breakers doesn’t lower proportionally with load discount, the most typical vitality saving strategies for electrical interconnection methods are primarily:

① Consolidate community visitors into fewer hyperlinks and switches and disable idle community gadgets; ② Scale back the hyperlink velocity to avoid wasting the ability consumption of the transmitter. The above two strategies will result in lack of efficiency to a sure extent.

Benefits of Optical Interconnect expertise

Optical interconnect expertise has nice potential to resolve the above issues. Beneath very best circumstances, the Helios photovoltaic hybrid community can save 2 occasions the price, 5 occasions the tools and eight occasions the vitality consumption of the grid in comparison with the electrical grid of the identical scale. The primary the explanation why optical hyperlink structure can obtain the above optimization are the next components.

By way of transmission bandwidth, coherent receivers based mostly on 100 Gbps PM-QPSK modulation have been commercially obtainable. Mixed with DWDM expertise, the transmission bandwidth of a pair of single-mode optical fibers can attain 12Tbps. Moreover, by way of transmission distance, the present non-repetitive transmission distance of multimode fiber and single-mode fiber can simply meet the interconnection requirement within the knowledge heart;

By way of switching capability, the optical swap structure can obtain larger switching capability.

It is because:

① The loss and distortion of high-speed optical alerts is way smaller than that {of electrical} alerts;

② With wavelength division multiplexing expertise, the variety of channels in a single optical waveguide may be elevated by dozens of occasions;

By way of community prices, the optical fiber has the next bandwidth, smaller cross-sectional space and lighter weight, so it could result in higher thermal conductivity and scale back the price of community wiring. On the identical time, as a result of most optical swap modules have the characteristic of clear transmission for sign fee, modulation mode, protocol, and so on., the community can improve the port bandwidth with out changing the optical swap tools.

As well as, as a result of optical switches can obtain larger switching capability and better connection density, many all-optical interconnect networks or optical-electrical hybrid networks can obtain a flat structure design. This considerably reduces tools and community administration prices;

By way of energy consumption, optical interconnect expertise can successfully resolve the trade-off between energy consumption and efficiency.

That is primarily as a result of:

① The optical sign has decrease loss and longer transmission distance, so the optical hyperlink can use decrease transmission energy;

② For the common optical swap structure, the sign doesn’t must expertise O/E (optical-electrical) and E/O (electrical-optical) conversion course of;

③ The optical swap structure may be constructed utilizing passive or low-power optics, so it could additional scale back the ability consumption of the community.


It may be seen that because of limitations in communication bandwidth, switching capability, tools value and vitality consumption, it’s troublesome for electrical interconnection networks to fulfill the communication wants of cloud computing knowledge facilities. Subsequently, optical interconnect expertise with excessive bandwidth and low energy consumption has been supported by the main focus of researchers. Particularly with the event of silicon photonics and optical integration expertise, the price of optical switching tools is reducing, which promotes the appliance and deployment of optical interconnect expertise in knowledge facilities.

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