ASR-9900-SFC-FILR Cisco ASR 99xx Switch Fabric Card

Understanding the Cisco ASR-9900-SFC-FILR Model

The part number ASR-9900-SFC-FILR decodes key specifications about this fabric card. "ASR-9900" denotes the chassis family, "SFC" confirms it is a Switch Fabric Card, and the suffix "FILR" is crucial. This suffix indicates a specific performance tier and feature set within the fabric card portfolio. The "F" typically denotes a full-height card for the largest ASR 9912 and ASR 9922 chassis. The "ILR" components often refer to integrated capabilities for intelligent load distribution and redundancy features optimized for the 400G-capable line cards. This card is engineered to work in unison with other fabric cards (in N+M redundancy configurations) to deliver the non-blocking, centralized switch fabric that the ASR 9900 is renowned for.

Role and Placement in the ASR 9900 Chassis

Fabric cards are installed in dedicated slots at the rear of the ASR 9912 and ASR 9922 routers. They are not field-upgradeable processors but are installed as pairs or sets to form the complete fabric complex. The Cisco ASR-9900-SFC-FILR operates by receiving cellified data from ingress line cards via high-speed serial connections, performing arbitration and scheduling within the fabric, and then forwarding the data to the appropriate egress line card. This centralized fabric architecture separates the control plane (handled by the Route Processor) from the data-switching plane, allowing for independent scalability and unprecedented stability.

Key Architectural Advantages

Non-Blocking Fabric Design

The primary design goal of the SFC is to provide a non-blocking switch fabric. This means the aggregate bandwidth of the fabric capacity exceeds the total bandwidth of all line cards simultaneously transmitting at full capacity. The ASR-9900-SFC-FILR is integral to achieving this, ensuring that no contention occurs for internal resources, thus guaranteeing line-rate performance on all ports regardless of traffic patterns.

Centralized Arbitration and Scheduling

Unlike distributed systems, the centralized fabric with cards like the FILR uses sophisticated algorithms to manage traffic flow. This provides deterministic latency and fair bandwidth allocation across all services—critical for maintaining Service Level Agreements (SLAs) for both residential broadband and high-frequency trading applications.

Technical Specifications and Performance Capabilities

The Cisco ASR-9900-SFC-FILR is built for the highest tier of performance. It supports the advanced fabric capabilities required for the latest generation of Cisco Silicon One Q200 series-based line cards, enabling 400GbE and beyond.

Fabric Bandwidth and Scalability

A single ASR-9900-SFC-FILR contributes a massive quantum of switching capacity to the fabric complex. Multiple cards are combined to scale the total system capacity into the hundreds of terabits per second. This modular scalability allows network operators to start with a configuration matching their current needs and expand fabric capacity by adding more SFCs alongside new line cards, protecting their initial investment.

Redundancy and High Availability Features

Network uptime is paramount, and the fabric design reflects this. The ASR-9900-SFC-FILR supports N+M redundancy models, where "N" is the minimum number of cards needed for full bandwidth and "M" are additional cards for backup.

Hitless In-Service Software Upgrade (ISSU) and Fabric Failover

The system is designed so that a single fabric card failure, or the removal of one for maintenance, does not cause traffic loss. Traffic is redistributed seamlessly among the remaining active fabric cards. This, combined with ISSU supported by the Cisco IOS XR software, allows for planned maintenance and software upgrades without service interruption.

Power and Cooling Requirements

As a high-performance hardware component, the SFC consumes a significant amount of power and generates heat. Proper chassis power supply configuration and adherence to thermal management guidelines in the data center are essential for long-term reliability. The ASR 9912/9922 chassis with FILR cards demand robust, fault-tolerant power and cooling infrastructure.

Common Diagnostics and Alarms

Fabric Utilization Metrics

Continuous monitoring of per-fabric-card and aggregate fabric utilization helps predict capacity bottlenecks before they impact service. Tools like the Embedded Event Manager (EEM) can be configured to trigger alerts at defined thresholds.

Identifying and Isolating Fabric Errors

CRC errors, cell drops, or other fabric-level anomalies logged by the system can indicate issues with a specific fabric card, its backplane connections, or an associated line card. Isolating the faulty component is a systematic process detailed in Cisco's technical documentation.

Evolution and Comparison Within the ASR 9000 Fabric Family

The Cisco ASR-9900-SFC-FILR exists within a broader ecosystem of fabric cards, each tailored for different chassis and performance levels.

Comparison to Other SFC Models (e.g., SFC-FIC, SFC-FIL)

Earlier or different variants, such as the SFC-FIC for the ASR 9904/9906 or the SFC-FIL, may offer different capacity points or be designed for smaller form-factor chassis. The "FILR" variant typically represents a later generation with enhancements for higher serdes speeds, improved power efficiency, and support for the most advanced line cards. It is crucial to consult the official Cisco hardware compatibility matrix to select the correct fabric card for a specific chassis and line card combination.

Applications and Use Cases

The performance enabled by the ASR-9900-SFC-FILR makes it suitable for the most demanding network roles.

Service Provider IP/MPLS Core and Peering

In the core of a Tier 1 or Tier 2 service provider network, where hundreds of gigabits of aggregated traffic must be switched with extreme reliability and low jitter, the non-blocking fabric is indispensable. It ensures that peering traffic, internet transit, and MPLS VPN services do not interfere with each other.

5G Mobile Transport (xHaul)

The transition to 5G demands massive bandwidth, strict latency guarantees, and network slicing from the transport network. The ASR 9900 with FILR fabric cards provides the ideal foundation for 5G fronthaul, midhaul, and backhaul (xHaul), carrying traffic from cell sites to the core with the required performance isolation.

Support for Network Slicing

The combination of the hardware fabric and Cisco IOS XR software enables true end-to-end network slicing. The fabric's quality-of-service (QoS) mechanisms and scheduling policies can isolate resources for a dedicated 5G slice, guaranteeing its performance independently from other slices or best-effort traffic.

Large-Scale Data Center Interconnect (DCI)

Connecting massive data centers requires routers that can handle sustained, high-volume flows with high availability. The redundancy and scale provided by the ASR 9900 fabric make it a premier choice for DCI, where a fabric card failure cannot be allowed to sever the critical link between facilities.