INTELLIGENT CABLING
Datacentres need to consider changing server connections when migrating to higher speeds
T he need for higher data transmission speeds is swiftly increasing across the datacentre . Whilst 400 Gigabit speeds are gradually being adopted for uplinks between switch tiers to handle the growing amount of data , server connections are under increased pressure to keep up with e-commerce and emerging technologies .
To support applications such as advanced data analytics , machine learning , artificial intelligence and high-resolution video content , datacentre server connections must provide more bandwidth and lower latency .
Datacentre professionals should therefore consider deploying high-performance Direct Attach Copper Cables , DACs or Active Optical Cables , AOCs when migrating server connections to nextgeneration speeds . These solutions can deliver performance , reliability , scalability and power efficiencies to cost-effectively adopt these emerging technologies .
DACs and AOCs are specifically suited in datacentres that rely on a top-of-rack , ToR switching architecture , such as hyperscale , cloud and colocation locations and large enterprise datacentres . In a ToR configuration these cables connect the switch located at the top of each rack with active equipment , e . g . server or storage devices in the same or in adjacent racks .
They support transmission speeds from 10Gbps to 100Gbps for when datacentres are upgrading their network equipment from 10Gbps to 25 and 100Gbps . For scalability and further growth , they can support 25 and 100 Gig switch connections with backward compatibility .
SFP + DACs for example are well suited in direct short-reach connections from ToR switches where lengths are less than 7 meters . They require less power per port and offer lower latency than a structured cabling 10GBASE-T solution . ToR switches with DACs typically use less than 1 W per port , while 10GBASE-T switches range from 1.5 to 4 W per port .
Latency with ToR and DACs is around 0.3 microseconds per links compared to 10GBASE-T where latency is closer to 3 microseconds per link . This makes DACs ideal for any current or future application where latency is a concern and where high port counts can add up to significant power savings .
Where large enterprise datacentres are now beginning to adopt 25 Gbps server connection speeds , they can take advantage of SFP28 DACs . These SFP28 DACs use the same form factor as SFP + DACs to support 25 Gbps whilst the benefits of reduced power consumption , lower latency , and lower remain the same at these speeds .
Although more expensive than DACs , AOC scan support uplinks to 100 meters and utilise OM3 multimode fibre . This makes AOCs well suited for deployment in row-to-row connections , example from the ToR switch to the aggregate switch that can be located several rows away . The smaller diameter of fibre allows for better air flow , but attention must be paid to heat generation which is greater in AOCs than in DACs .
When migrating server connections to next-generation speeds , Direct Attach Copper Cables or Active Optical Cables can be a valuable alternative to other cabling options . Datacentre professionals can benefit from greater bandwidth and improved latency at lower costs . •
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