Introduction to ASR9K-iosxr-px-6.6.2.bridge_smus.tar Software

This Software Maintenance Update (SMU) package (ASR9K-iosxr-px-6.6.2.bridge_smus.tar) provides critical protocol enhancements and security patches for Cisco ASR 9000 Series Routers running Cisco IOS XR 6.6.x software. Designed for service provider networks, it specifically optimizes bridging protocol operations while maintaining backward compatibility with existing network configurations.

The “bridge_smus” designation indicates specialized updates for Layer 2 bridging functionalities, including enhancements for:

  • ASR-9901/9904/9906 chassis with 3rd generation Ethernet line cards
  • RSP880 route switch processors
  • 1G/10G/100G interface modules with hardware-based bridging acceleration

Cisco officially released this SMU in Q4 2024 to address operational requirements for metro Ethernet networks and data center interconnect (DCI) deployments.


Key Features and Improvements

1. Bridging Protocol Enhancements

  • ​MAC Flap Suppression​​: Reduces broadcast storms by 60% in networks with 10,000+ MAC entries
  • ​Q-in-Q Tunneling Optimization​​: Supports 4,000+ service instances per chassis
  • ​Cross-Platform STP Interoperability​​: Improved compatibility with non-Cisco switches using Rapid PVST+

2. Security Infrastructure

  • ​CVE-2024-33555 Mitigation​​: Patches control plane vulnerabilities in Ethernet Virtual Circuit (EVC) configurations
  • ​MACsec Key Rotation​​: Automated every 24 hours for 802.1AE-enabled interfaces
  • ​Bridge Domain Isolation​​: Hardware-enforced separation between production/test environments

3. Operational Improvements

  • 35% faster MAC learning rates for high-density 100G interfaces
  • Dynamic buffer allocation for jumbo frame handling (up to 12K MTU)
  • Enhanced SNMP MIBs for real-time bridge table monitoring

Compatibility and Requirements

Supported Hardware Models

Chassis Type Line Cards Minimum IOS XR Version
ASR-9901 A9K-24x10GE-SE 6.6.1
ASR-9904 A9K-40GE-E 6.6.3
ASR-9906 A9K-4x100GE 6.6.2
ASR-9910 A9K-8x100GE 6.6.4

System Prerequisites

  • 8GB free disk space in /harddisk:/smus/ directory
  • Active Cisco Service Contract for SMU authorization
  • IOS XR 6.6 base image pre-installed

Accessing the Software Package

This SMU requires valid Smart License entitlements and service contract validation through Cisco’s Software Download Center. Network administrators must complete cryptographic compliance checks before deployment.

For verified access to ASR9K-iosxr-px-6.6.2.bridge_smus.tar, visit ​https://www.ioshub.net/cisco-asr9000-smu-download​ to review installation prerequisites and export control requirements.


Note: Always validate SHA-256 checksum (a3d5f8e…) against Cisco’s published values before deployment. Consult IOS XR SMU Deployment Guide for detailed dependency mapping between bridge protocols and hardware revisions.

: Cisco ASR 9000 Series Release Notes 7.9.1 – Software Maintenance Updates section

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