ASR-9904-AC: How Does Cisco’s 4-Slot Chassis Deliver Scalability for Core Network Demands?



​What Is the ASR-9904-AC?​

The ​​ASR-9904-AC​​ is a 4-slot modular chassis from Cisco’s ASR 9000 Series, designed for ​​high-performance core and peering networks​​. It supports AC power supply configurations, delivering up to 9.6 Tbps of system capacity while maintaining carrier-grade reliability. The chassis serves as the backbone for service providers and hyperscalers requiring dense 100G/400G interfaces, advanced QoS, and seamless integration with SDN architectures.


​Core Technical Specifications​

  • ​Slots​​: 4 (2 for route processors, 2 for line cards or additional redundancy).
  • ​Throughput​​: 9.6 Tbps with Cisco’s Quantum Flow Processor.
  • ​Power​​: Dual 3000W AC power supplies (N+1/N+N redundancy).
  • ​Software​​: Cisco IOS XR for modularity, Segment Routing, and EVPN support.
  • ​Cooling​​: Front-to-back airflow with variable-speed fans (ASR-9904-FAN= modules).

​Key Use Cases and Operational Advantages​

​1. Internet Peering and Core Aggregation​

The chassis’s 400G-ready line cards (e.g., A9K-4X100GE-SE) enable high-density peering for Tier 1 ISPs and cloud exchanges.

​2. 5G Core Network Transport​

Supports network slicing and low-latency forwarding (<10µs) for 5G SA (Standalone) architectures.

​3. DCI (Data Center Interconnect)​

Deploys MACsec encryption on 400G links, ensuring secure hyperscaler connectivity over DWDM networks.


​ASR-9904-AC vs. Larger ASR 9000 Chassis​

​Feature​ ​ASR-9904-AC​ ​ASR-9910 (10-slot)​
​Slots​ 4 10
​Max Capacity​ 9.6 Tbps 24 Tbps
​Power Draw​ 4.5 kW (fully loaded) 12 kW (fully loaded)
​Use Case Focus​ Regional core, medium-scale DCI National backbone, mega-scale peering

​Addressing Critical Deployment Questions​

  • ​Can It Support Legacy Line Cards?​
    Yes, backward-compatible with older A9K line cards (e.g., A9K-40GE-B), but throughput may be limited.

  • ​How to Ensure Zero Downtime Upgrades?​
    Use In-Service Software Upgrades (ISSU) with dual route processors (RSP880 modules).

  • ​What Cooling Is Required?​
    Deploy in data centers with front-to-back airflow (≥200 CFM) and 20–25°C ambient temperature.


​Where to Purchase the ASR-9904-AC​

For validated hardware and Cisco Smart Net support, the ASR-9904-AC chassis is available at itmall.sale, including optional line cards and extended warranties.


​Practical Insights from Core Network Deployments​

In a recent deployment for a European ISP, the ASR-9904-AC’s modularity allowed a phased upgrade from 100G to 400G without chassis replacement—cutting CapEx by 40% compared to forklift upgrades. While its 4-slot design limits ultimate scalability, it strikes a balance for operators needing future-proofing without overcommitting to underutilized capacity. Cisco’s focus on backward compatibility ensures even early-generation line cards remain viable, making it a strategic choice for evolving core networks.

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