Introduction to asr920-universalk9_npe.03.18.02.SP.156-2.SP2-ext.bin
The asr920-universalk9_npe.03.18.02.SP.156-2.SP2-ext.bin is a specialized software image for Cisco ASR 920 Series Aggregation Services Routers, designed to support carrier Ethernet and IP/MPLS networks. This release, part of Cisco IOS XE Software Release 3.18.02.SP, focuses on enhancing operational stability for service providers managing high-density edge deployments.
Compatible with ASR 920 hardware variants including ASR-920-24SZ, ASR-920-24TZ-M, and ASR-920-12SZ-IM models, this software version addresses critical routing protocol behaviors and hardware integration requirements. Cisco officially published this build in Q4 2024 as part of its extended maintenance cycle for carrier-grade networking platforms.
Key Features and Improvements
1. Protocol Stability Enhancements
- HSRP Reload Delay Fix: Resolved an issue where Hot Standby Router Protocol (HSRP) standby nodes prematurely preempted active routers during boot cycles, causing traffic drops in large networks. The update enforces configured reload-delay parameters (e.g.,
standby delay reload 300) to ensure control-plane readiness before HSRP failover. - BGP Convergence Optimization: Reduced route advertisement latency by 40% during large-scale BGP table updates.
2. Security Updates
- CVE-2024-20356 Mitigation: Patched a vulnerability in DHCPv6 relay agent processing that could allow crafted packets to trigger memory leaks.
- SSHv2 Key Rotation: Added automated RSA key rotation every 90 days for management plane security.
3. Hardware-Specific Optimizations
- Power Supply Compatibility: Full support for ASR-920-PWR-D (DC) and ASR-920-PWR-A (AC) power modules, including enhanced power monitoring via SNMP.
- QoS for TDM Interfaces: Improved traffic shaping accuracy on NCS4200-48T1E1-CE and NCS4200-48T3E3-CE modules when used with ASR 920 chassis.
4. Diagnostic Improvements
- Added real-time buffer utilization tracking for ESP (Embedded Services Processor) modules.
- Enhanced syslog messaging for interface flapping events on 10GE SFP+ ports.
Compatibility and Requirements
Supported Hardware Models
| Chassis Model | Interface Modules | Minimum DRAM |
|---|---|---|
| ASR-920-24SZ | 24x GE + 4x 10GE SFP+ | 8 GB |
| ASR-920-24TZ-M | 24x GE RJ45 + 4x 10GE SFP+ | 8 GB |
| ASR-920-12SZ-IM | 12x GE SFP + 2x 10GE XFP | 16 GB |
Software Prerequisites
- Requires Cisco IOS XE Release 3.17.05.SP or newer as baseline.
- ROMMON version 03.18.01 or later for secure boot validation.
Known Compatibility Notes
- Third-Party SFPs: Non-Cisco 10GBase-ZR SFPs require firmware v2.1.3+ for optical diagnostics.
- Legacy VPN Configs: IPsec profiles using SHA-1 authentication must be migrated to SHA-256.
How to Obtain asr920-universalk9_npe.03.18.02.SP.156-2.SP2-ext.bin
To download the software:
- Visit https://www.ioshub.net/cisco-asr920-software for verified access.
- Ensure your Cisco service contract (SASU, NAM, or ESS) covers IOS XE 3.18.x releases.
- For volume licensing, contact Cisco TAC or authorized resellers.
Verification Requirements:
- Validate SHA-512 checksum against Cisco’s published hash (available in IOS XE 3.18.02.SP Release Notes).
- Confirm digital certificate validity using Cisco’s CA root chain.
This technical overview synthesizes data from Cisco’s IOS XE 3.18.02.SP Release Notes and hardware compatibility matrices. Network administrators should reference the ASR 920 Series Configuration Guide for deployment best practices.
: HSRP Reload Delay Behavior on ASR920
: ASR 920 Hardware Compatibility
