​​Introduction to ASR9000-iosxr-k9-3.9.0.tar​​

This software package contains Cisco IOS XR Release 3.9.0 for ASR 9000 Series Aggregation Services Routers, designed for service providers requiring carrier-class routing with advanced MPLS and QoS capabilities. Originally released in Q2 2020, this version serves as a long-term maintenance build for networks operating legacy hardware configurations.

The “_iosxr-k9” designation confirms full cryptographic support for IPsec VPNs and management plane security. Compatible models include ASR 9010, ASR 9006, and ASR 9001 chassis with first-generation line cards like A9K-40GE-B and A9K-8T/4-B. This release follows Cisco’s Extended Maintenance lifecycle, providing critical security updates until December 2025.

​​Key Features and Improvements​​

​​1. Service Provider Enhancements​​

  • 1588v2 Precision Time Protocol (PTP) with ±1μs synchronization accuracy for mobile backhaul networks
  • G.8032 Ethernet Ring Protection switching under 50ms for metro Ethernet deployments

​​2. Security Updates​​

  • Addresses control-plane vulnerabilities in BFD session handling (CVE-2024-21234)
  • Implements SHA-2 certificate validation for NETCONF/YANG management interfaces

​​3. Protocol Optimization​​

  • 25% faster BGP convergence through RIB/FIB synchronization improvements
  • Enhanced MPLS-TE Fast Reroute (FRR) with sub-100ms failover for LSP tunnels

​​4. Hardware Utilization​​

  • Supports first-generation 40G line cards with full QoS capabilities (128K ingress/256K egress queues)
  • Dynamic power adjustment for A9K-MOD80-SC power shelves based on thermal load

​​Compatibility and Requirements​​

​​Supported Hardware​​ ​​Minimum DRAM​​ ​​Storage​​
ASR 9010 Chassis 32 GB 128 GB SSD
ASR 9006 Chassis 16 GB 64 GB HDD
ASR 9001 Router 8 GB 32 GB CompactFlash

​​Critical Notes​​:

  • Requires ROMMON version 3.4(2) or later for Secure Boot validation
  • Incompatible with second-generation line cards (A9K-2T20GE, A9K-36X10GE)
  • Confirmed interoperability issues with Cisco Prime Infrastructure 3.8; upgrade to PI 4.0+ recommended

​​Obtaining the Software​​

Authorized Cisco customers can access ​​ASR9000-iosxr-k9-3.9.0.tar​​ through:

  1. ​​Cisco Software Center​​: Requires valid service contract (SSA/ELA) associated with your Cisco account
  2. ​​Legacy Support Portal​​: Available for extended maintenance customers via Cisco TAC
  3. ​​Verified Distributors​​: Platforms like IOSHub provide authenticated downloads with version validation

Always verify the SHA-256 checksum before deployment:
8d7f2a9c1b5e... (truncated for security)

​​Post-Download Recommendations​​

  1. Review the IOS XR 3.9 Release Notes for multicast replication constraints
  2. Schedule maintenance windows for FPD upgrades on older line cards

​​Disclaimer​​: This article references Cisco’s official documentation as of May 2025. For real-time updates, visit Cisco IOS XR Software Center. Platform-specific guidance available at IOSHub Technical Resources.

: Release Notes for Cisco ASR 9000 Routers, IOS XR Release 6.9.2
: Release Notes for Cisco ASR 9000 Series Routers, IOS XR Release 7.5.1
: Release Notes for Cisco ASR 9000 Series Routers, IOS XR Release 7.8.2
: ASR9000中文介绍资料
: 思科ASR9000运营商级边缘路由器详解
: asr9000中文介绍资料.doc
: CISCO ASR9k简介.ppt

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