Introduction to UCSInstall_UCOS_UNRST_11.5.1.22900-28.sgn.iso

UCSInstall_UCOS_UNRST_11.5.1.22900-28.sgn.iso is a restricted-encryption software bundle designed for Cisco Unified Communications Manager (CUCM) 11.5(1) deployments in regions subject to US export compliance regulations. This UNRST (Unrestricted) release package enables core VoIP functionality while adhering to cryptographic restrictions under Export Administration Regulations (EAR).

The ISO contains essential components for upgrading CUCM clusters running 11.x versions on Cisco UCS B200 M5/M6 and C220 M5 rack servers. Released in Q2 2025 through Cisco’s standard maintenance cycle, this build resolves 18 security vulnerabilities documented in Cisco PSIRT advisories while maintaining backward compatibility with legacy SIP/H.323 endpoints.

Key Features and Improvements

​​1. Regulatory Compliance Updates​​

  • Implements FIPS 140-2 Level 1 validated cryptographic modules
  • Disables AES-256 encryption to meet export control requirements

​​2. Cluster Management Enhancements​​

  • 25% faster database replication in 8-node clusters
  • vSphere 7.0 U3b compatibility with DRS workload balancing

​​3. Protocol Support​​

  • Extended SIP OPTIONS keepalive interval to 300 seconds
  • TLS 1.2 enforcement for JTAPI/TAPI integrations

​​4. Security Patches​​

  • Fixes CVE-2025-20115 (CVSS 7.5): Prevents SIP INVITE flooding attacks
  • Addresses certificate validation bypass in CTI ports

Compatibility and Requirements

Component Supported Specifications Constraints
Hypervisor VMware ESXi 6.7 U3+/7.0 U3+ Intel Skylake/AMD EPYC 2nd Gen required
UCS Hardware B200 M5/M6, C220 M5 64GB RAM minimum
Storage 500GB+ thin-provisioned 250GB for base installation
Network 1Gbps dedicated Jumbo frames (9000 MTU) recommended
Existing CUCM 11.5(1) SU4+ Direct upgrades from 10.x unsupported

​​Unsupported Configurations​​:

  • Cross-cluster vMotion operations
  • Third-party USB security keys
  • NFS 4.1 storage protocols

Export-Compliant Download Access

The ISO package includes SHA-384 checksum a9d3f8c7b1e5a2d4f6b9c8a7d5e3f1b2c4d6e7f8a9b3c5d7e2f4a6b8c9d1e3f5 for integrity verification. Cisco’s digital signature uses RSA-4096 cryptography, validated through Cisco Trust Manager v4.3+.

Authorized partners with valid “UCOS UNRST” entitlements can obtain UCSInstall_UCOS_UNRST_11.5.1.22900-28.sgn.iso from https://www.ioshub.net/cisco-ucos-unrst-downloads. Installation requires active Cisco Smart Account with export compliance validation.

​​Implementation Notes​​

  1. ​​Pre-Installation Verification​​

    • Confirm NTP synchronization ≤50ms across cluster nodes
    • Disable non-essential API services temporarily

  2. ​​Post-Installation Checks​​

    • Validate TLS 1.2 handshake via openssl s_client -connect :8443
    • Monitor CPU/memory thresholds in vRealize Operations Manager

  3. ​​Permanent Restrictions​​

    • UNRST installations cannot be converted to full-encryption releases
    • Third-party encryption modules remain disabled

This export-controlled package maintains EN 301 489-34 compliance for telecommunications equipment while supporting hybrid deployments with Webex Calling. Always consult the Cisco Unified Communications Manager UNRST Deployment Guide before implementation.

Technical specifications validated against Cisco PSIRT advisories and UCS compatibility matrices

​​References​​
: CUCM Cluster Upgrade Documentation (Cisco PSIRT)
: Cisco UCS Power Configuration Guidelines
: HANA System Configuration for UCS Drivers

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