Cisco SD-AR3K-DPO4QS1E 400G ZR Router | Enterprise WAN, QSFP-DD — SD-AR3K-DPO4QS1E

Move 400G traffic farther with the optical margin needed for demanding transport designs. Cisco SD-AR3K-DPO4QS1E pairs QSFP-DD 400G ZR connectivity with high transmit power, helping infrastructure teams preserve reach across metro and regional links where optical loss can quickly limit deployment options. This model is positioned for environments that need high-capacity routing hardware without bundled software support. That makes it a strong fit for teams standardizing on their own control-plane, automation, or service-layer stack while still requiring a Cisco platform built for dense optical interconnects. For architects planning aggregation, backbone extension, or data center interconnect, the value is in the optical headroom. Higher transmit power can simplify link design, reduce the need for additional compensation in the path, and give teams more flexibility when mapping 400G services across existing fiber plant. Use it where link reach, port density, and predictable transport behavior matter more than feature bundling. It is a focused hardware choice for organizations that want to buy only the routing capability they need and keep the rest of the stack under their own operational model. Ideal For Extend 400G metro transport between data centers Build long-reach backbone links across regional fiber spans Add high-capacity optical routing to aggregation layers Deploy hardware-only routing in standardized enterprise control stacks Why This Product 1 Higher optical reach than standard 400G optics 2 Hardware-only design for controlled software environments 3 QSFP-DD form factor for dense transport architectures 4 Built for long-reach metro and backbone interconnects