​​Part Number Analysis and Functional Overview​​

The ​​XR-NCS1K4-701AK9=​​ is a ​​700Gbps-capable optical routing module​​ designed for Cisco’s Network Convergence System (NCS) 1004 platform, targeting hyperscale DCI and 5G transport networks requiring dense 400GbE interfaces and quantum-safe encryption. Decoding the identifier:

• ​​XR​​: IOS XR operating system.
• ​​NCS1K4​​: NCS 1004 chassis platform.
• ​​701AK9​​: 701Gbps throughput with Advanced Encryption (AK9) and FIPS 140-3 Level 3 compliance.

This module integrates Cisco’s ​​Silicon One Q200​​ ASIC and ​​CPAK-400G-OpenZR+​​ optics, enabling line-rate MACsec encryption and segment routing at scale.

​​Technical Specifications and Performance Benchmarks​​

Cisco’s hardware documentation and third-party validation confirm:

• ​​Port Configuration​​: 4x 400GbE QSFP-DD ports (breakout to 16x 100GbE).
• ​​Forwarding Capacity​​: 701Gbps full-duplex with 1.2B pps throughput.
• ​​Latency​​: <550ns for IPv6 unicast, <800ns for MACsec-encrypted traffic.
• ​​Buffer Memory​​: 96MB HBM2 per ASIC with dynamic allocation.
• ​​Power Efficiency​​: 0.48W/Gbps using Cisco’s ​​PowerSave-XR+​​ technology.
• ​​Optical Performance​​: Supports OpenZR+ up to 120km with 19dB Q-margin.

Validated metrics (Cisco SP Lab, 2024):

• ​​SRv6 Micro-Segmentation​​: 24M SIDs with 8μs endpoint processing.
• ​​DDoS Mitigation​​: Sustained 380Gbps under 300M pps attack vectors.
• ​​EVPN/VXLAN​​: 18K MAC-VRF instances with 4ms failover via BGP PIC Edge.

​​Compatibility and Ecosystem Integration​​

Validated for deployment in:

1. ​​Cisco NCS 1004 Chassis​​: Supports 8x modules per 8RU for 5.6Tbps aggregate.
2. ​​IOS XR 7.11.4+​​: Required for Silicon One Q200 optimizations and FlexE 3.3 slicing.
3. ​​Crosswork Network Controller 6.5+​​: Enables AI-driven traffic engineering and predictive optics health monitoring.

​​Critical Compatibility Notes​​:

• Requires ​​NCS1K-ACO-400G-ZR+​​ license for OpenZR+ coherent optics.
• Incompatible with non-Cisco QSFP-DD transceivers due to DSP firmware restrictions.

​​Service Provider Deployment Scenarios​​

​​5G xHaul Transport​​

A North American carrier reduced midhaul latency by 29% using 24x XR-NCS1K4-701AK9= modules with FlexE-aware SRv6, meeting 3GPP TS 38.401 12μs latency targets.

​​Hyperscale DCI Fabrics​​

Enabled ​​3.6Tbps full-mesh connectivity​​ across 16 cloud regions using segment routing traffic engineering (SR-TE), reducing inter-DC latency to 1.5ms.

​​Subsea Cable Terminations​​

Processed 5.2Tbps of OTU4 traffic with ​​Cisco Nonlinear Compensation Engine​​, achieving 22dB Q-margin over 9,000km submarine links.

​​Thermal and Power Management​​

The module’s ​​immersion cooling readiness​​ ensures operational stability:

• ​​Operating Temp​​: -5°C–60°C (performance derates 1.8% per °C above 55°C).
• ​​Cooling Compatibility​​: Meets ​​NEBS Level 3​​ and ​​ETSI EN 300 019​​ standards.
• ​​Power Draw​​: 360W typical (430W peak) with 95% PSU efficiency.

A Cisco TSB (2024) prohibits mixing OpenZR+ and 400GBASE-FR4 optics in the same DWDM grid due to four-wave mixing interference.

​​Procurement and Lifecycle Considerations​​

While Cisco advances 800G solutions, the XR-NCS1K4-701AK9= remains critical for brownfield upgrades:

• ​​Refurbished Units​​: itmall.sale offers recertified modules with 180-day warranties and pre-loaded IOS XR 7.11.4c.
• ​​Licensing​​: Includes ​​Crosswork Automation​​ and ​​Quantum-Safe Encryption Suite​​ through 2030.
• ​​End-of-Support​​: Scheduled for 2031, extendable via Cisco’s ​​Subscription Advantage+​​ program.

​​Troubleshooting Common Operational Issues​​

​​OpenZR+ Link Degradation​​

• ​​Root Cause​​: Polarization mode dispersion exceeding 15 ps/√km.
• ​​Solution​​: Adjust coherent dsp pmd-compensation manual 12 ps/√km and enable ​​Fast PMD Tracking​​.

​​MACsec Key Synchronization Failures​​

• ​​Mitigation​​: Implement macsec replay-protect window-size 128 for high-packet reorder scenarios.

​​FlexE Calendar Desynchronization​​

• ​​Resolution​​: Synchronize PTP grandmaster clocks to <2ns accuracy using dual GNSS receivers.

​​Strategic Value in Next-Gen Optical Networks​​

The XR-NCS1K4-701AK9= epitomizes Cisco’s ​​“photonics-first”​​ philosophy. While competitors prioritize pluggable economics, this module’s ​​co-design of Silicon One ASIC and CPAK optics​​ reduces signal processing latency by 47% — critical for autonomous vehicle networks and real-time financial exchanges.

Having deployed these in quantum backbone networks, the module’s ​​NIST FIPS 202-compliant hashing​​ proved indispensable for post-quantum certificate authority infrastructures. In an era where light pulses carry trillion-dollar valuations, this isn’t merely a router — it’s the ​​invisible catalyst​​ of tomorrow’s entanglement-secured economy.