Data center connectivity sits behind almost every performance, cost, and reliability decision network teams make today. As data rates climb from 200G toward 800G and beyond, the choices made in cabling, transceivers, and interconnects ripple through latency, power draw, and total cost of ownership across the whole facility.
AddOn Networks’ expert guide walks through the connectivity challenges data centers face today. This includes the trade-offs between the main solutions available, and what's changing as AI and GPU workloads reshape demand.
What are the unique connectivity challenges data centers are facing today?
Data centers are facing a range of connectivity challenges as networks evolve to support higher speeds. In the process, they need to deal with the demand for greater efficiency and increasingly taxing applications.
Key challenges that are facing the data centers of today include:
- Generational Technology Shifts –PAM4 modulation is enabling network growth to 200G and higher data rates in data centers. PAM4 also introduces complexities to the network; however, it is not backward compatible with legacy NRZ modulated links. Additionally, the DSPs onboard to transceivers and cabling may increase both power consumption and network latency.
- Operating cost/power consumption – In particular, data center power consumption metrics are top of mind for any organization. Every watt counts to reduce costs over the useful life of IT equipment. The key challenge for data center operators is finding the balance between critical network upgrades and sustainability.
- Latency – In addition to that, high-performance computer applications driven by artificial intelligence, high-frequency trading, and 5G edge computing owe their success to low-latency networks. These networks require reduced latency at the host and even at the transceiver level
What connectivity solutions are being used to address these challenges?
Multi-coding capable solutions, including breakouts and DACs and AOCs, simplify multi-OEM environment connectivity and reduce both complexity and cost. In-field tunable transceivers are another effective approach: rather than stocking every fixed-wavelength variant, a tunable module can be retuned on site as needed, which reduces spare-part complexity and speeds up triage when a link fails.
For example, AddOn's Coding and Tuning Box applies this approach in practice. This retunes tunable transceivers in the field to cut stock complexity and repair failing links faster.
For longer-range access and DCI links, coherent and PAM4-based optics (such as ZR4) extend well beyond what short-range DAC or AOC solutions can cover.
How should components be selected for today's data center challenges?
Today’s networking upgrades increasingly rely on technologies such as Time-Sensitive Networking (TSN) and InfiniBand™ to support the demands of data-intensive applications.
Data center environments supporting 5G edge computing, hyperscale data center interconnects, high-frequency trading and financial technologies are adopting these technologies to minimize latency and improve network performance. At the same time, the introduction of PAM4 modulation has placed greater focus on the connectivity infrastructure required to support these higher-speed networks.
The first generation of PAM4 transceivers and active optical cables relied on DSPs to perform key modulation functions. The DSP introduced both latency and increased power consumption into the network. Passive DAC cables offer a low-latency and low-power solution for both 200G and 400G upgrades. DAC cables are great for in-rack, short-reach applications up to 2.5 meters, but beyond those reaches, other solutions are needed.
How can latency be reduced in modern data center networks?
All fiber optic networks must account for latency in their design and construction. Migrating away from DSP-based optics toward an analog clock and data recovery circuit (CDR) architecture is one of the more effective ways to cut latency, since it removes a processing step from the signal path entirely.
For example, AddOn's 200G active optical cable with a reach of more than 2m uses this CDR-based approach instead of DSP-based optics, reducing latency to a fraction of a DSP-based solution while also cutting overall power consumption.
How can help data centers reduce connectivity costs?
There's no one-size-fits-all solution for improving data center connectivity economics, but the biggest levers tend to be the same across environments. Namely, reducing power consumption per port, keeping hardware costs down relative to OEM equivalents, and extending the useful life of existing infrastructure rather than replacing it outright.
AddOn has helped data centers increase bandwidth and speed capabilities even with the rising demands of consumers.
DAC vs. AOC: Which should you choose for your data center?
Direct Attach Copper (DAC) cables and Active Optical Cables (AOC) solve the same short-reach connectivity problem in different ways.
DAC uses twinaxial copper to carry an electrical signal end to end, with no optical conversion. This keeps cost and power draw low and adds virtually no latency, but it limits reach, typically to a few meters for passive variants.
AOC integrates the optical transceiver directly into the cable assembly, converting the signal to light at each end. This extends reach well beyond copper, commonly tens of meters, and removes the electromagnetic interference issues that copper is prone to in dense racks. The trade-off is higher power consumption from the electro-optical conversion.
Explore more about the difference between these types of cables with our DAC vs. AOC guide.
How is AI and GU cluster growth changing data center connectivity?
The rise of large-scale AI training and inference has put connectivity under a different kind of pressure. GPU clusters generate enormous east-west traffic between nodes, and a single failed or high-latency link can stall an entire training run rather than just one workload. This has pushed data center operators toward a more deliberate approach to interconnects rather than a single default choice.
The common pattern across large deployments is copper inside the rack and optics outside it. Passive DAC is generally preferred for intra-rack GPU-to-switch connections because of its reliability and near-zero added latency, while AEC and AOC handle the slightly longer 3 to 7 meters and rack-to-rack distances where copper alone runs out of reach.
This shift is also accelerating the move to 800G optics today, with 1.6T deployments expected to follow at a faster generational pace than previous upgrades. For network engineers planning infrastructure now, the practical implication is ordering optical and cabling components well ahead of compute hardware arriving.
About AddOn Networks
For more than two decades, AddOn Networks has served the fiber and copper connectivity industries, including small business, data centers, enterprises, and governments. We operate a world-class in-environment network testing lab alongside localized support teams.
With a deep US/UK-based inventory, AddOn can deliver items fast. This is one of the primary reasons that companies prefer to work with us. Our world-class labs ensure a 99.98 percent reliability rate. The other factors include ease of doing business, quality, and the support we provide.
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