Release Notes for Cisco NCS 560 Series Routers, Cisco IOS XR Release 25.3.1
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Cisco NCS 560 Series Routers, Release 25.3.1
Cisco NCS 560 Series Routers, Release 25.3.1
Cisco IOS XR Release 25.3.1 is a new feature release for Cisco NCS 560 Series routers.
For more details on the Cisco IOS XR release model and associated support, see Software Lifecycle Support Statement - IOS XR.
Table 1. New software features for NCS 560 Series Routers, Release 25.3.1
| Product impact |
Feature |
Description |
| L2VPN |
||
| Software reliability
|
Decoupled mode improves fault tolerance by allowing the PE router to maintain the PW in an active state independently of the AC status. Unlike the traditional coupled mode, which requires both AC and PW to be active for traffic flow, decoupled mode ensures uninterrupted PW traffic even during AC failures. |
|
| Software reliability |
You can maintain continuous service in multi-homed EVPN deployments using sub-second convergence for EVPN with BGP PIC-edge. This functionality rapidly switches traffic to a backup nexthop path when the preferred nexthop fails, delivering fast convergence and high availability for active-active EVPN E-LAN and E-Line services. |
|
| Programmability |
||
| Software Reliability
|
YANG-Push provides a real-time telemetry solution by allowing applications to subscribe to specific YANG datastore updates. This feature enables efficient, low-latency streaming of operational state data to subscribed receivers. By reducing the reliance on traditional polling methods, YANG-Push enhances network observability, accelerates troubleshooting, and optimizes data collection for modern network automation and assurance workflows. |
|
| Segment Routing |
||
| Ease of Use
|
Cisco Network Controller (CNC) v7.2: Multiple SID-List with Preserve or Transactional gRPC API
|
This feature enables advanced segment routing path computation by supporting multiple SID lists and atomic, transactional updates through gRPC API. This ensures reliable, consistent policy changes and enhances network stability. |
| System Security |
||
| Software Reliability
|
Unused connection timeout for SSH sessions
|
You can prevent session limit exhaustion and maintain optimal system performance by automatically disconnecting SSH connections with no active channels. The feature introduces a configurable timeout for unused SSH connections, ensuring stale sessions do not occupy resources on your routers. The router monitors each SSH connection and terminates it when all channels remain closed and SSH clients do not create new channels within the configured timeout period. |
| Software Reliability
|
Channel timeout for SSH sessions
|
You can improve resource efficiency and minimize potential security risks by automatically closing idle SSH channels on the routers after a specific period of inactivity. The feature introduces a configurable timeout for SSH channels which ensures that unused channels do not persist while the parent SSH connection remains active. The router monitors each SSH channel and closes any channel where no data is sent or received within the configured timeout period. |
| API Experience
|
Optimize network scalability and interoperability by reducing SID resource usage, and enabling seamless integration between distinct SRv6 domains. The Layer 3 service gateway provides a flexible mechanism to extend Layer 3 services across different SRv6 networks, supporting efficient route summarization, cross-locator compatibility, and consistent service continuity on both control and data planes. |
|
| Security Efficacy |
You can significantly enhance security and reduce the risk of attacks on weak encryption by using TACACS+ over TLS. This method ensures the secure transmission of all Authentication, Authorization, and Accounting (AAA) data between the client and server. It provides robust protection for sensitive environments by supporting mutual authentication through a TLS X.509 certificate-based infrastructure. This feature is compatible with both TLS versions 1.3 and 1.2. |
|
This section provides a brief description of the new hardware features introduced in this release.
Table 2. New hardware features for Network Convergence System 560 Series Routers, Release 25.3.1
| Hardware |
Description |
| Optics |
*Note*: Optics support varies across devices (routers, line cards, RPs, and so on). To know if an optics is compatible with a specific Cisco device, refer to the Transceiver Module Group (TMG) Compatibility Matrix. This release introduces the following optics: ● DP01QS28-E20 (C-Temp) ● DP01QS28-E25 (I-Temp) |
| Optics |
*Note*: Optics support varies across devices (routers, line cards, RPs, and so on). To know if an optics is compatible with a specific Cisco device, refer to the Transceiver Module Group (TMG) Compatibility Matrix. This release introduces the following optics: ● Cisco 25/50GBASE-SL SFP56 Module for MMF ● SFP-50G-SL ● Cisco 25/50GBASE-SR SFP56 Module for MMF ● SFP-50G-SR-S ● Cisco 25/50GBASE-LR SFP56 Module for SMF ● SFP-50G-LR-S |
● Starting with Release 25.3.1, IOS XR software no longer supports Call Home transport mode for Licensing. Please configure CSLU or Smart Transport to ensure seamless operation of the licensing solution.
● Type6 server output enhancements: The show type6 server command now includes two new outputs that provides additional details for enhanced server management and troubleshooting:
◦ Masterkey Length
◦ Masterkey Hash
● gRPC remote-connection disable command: A new command, grpc remote-connection disable, has been introduced. This command allows users to disable TCP connections on the router, providing greater control over network configurations.
● The Cisco-IOS-XR-pmengine-oper.yang data model has been updated to ensure consistency. The naming convention has been standardized by renaming elements such as hour24fec to hour24-fec, minute15pcs to minute15-pcs, and second30pcs to second30-pcs across all layers, including OTN, OTNSEC, PCS, FEC, PRBS, Ether, and GFP. For more details on the sensor paths or the updated 25.2.1 YANG models, refer to the GitHub repository.
There are no open issues in this release.
● Telemetry data collection may timeout due to CPU overload during route churn. In such scenarios, telemetry will resume when the CPU becomes available after the route churn is complete.
● The standby RP may get into 'NOT READY' state intermittently due to some network churn, though the corresponding VM is up and running. But this is a transient state and shows that some data aren’t in sync between active and standby due to the network churn. After both active and standby are in sync with respect to all the parameters, then the standby RP comes into 'READY' state.
Compatibility Matrix for EPNM and Crosswork with Cisco IOS XR Software
The compatibility matrix lists the version of EPNM and Crosswork that are supported with Cisco IOS XR Release in this release.
Table 3. Compatibility matrix for Cisco NCS 560 Series Routers, Release 25.3.1
| Cisco IOS XR |
Crosswork |
EPNM |
| Release 25.3.1 |
System requirements
Use the show hw-module fpd command in EXEC and Admin mode to view the hardware components with their current FPD version and status. The status of the hardware must be CURRENT; Running and Programed version must be the same. You can also use the show fpd package command in Admin mode to check the fpd versions.
Software version
To verify the software version running on the router, use show version command in the EXEC mode.
Router# show version
Cisco IOS XR Software, Version 25.3.1
Copyright (c) 2013-2025 by Cisco Systems, Inc.
Build Information:
Built By : swtools
Built On : Mon Sep 15 07:15:40 PDT 2025
Built Host : iox-lnx-027
Workspace : /auto/srcarchive12/prod/25.3.1/ncs560/ws
Version : 25.3.1
Location : /opt/cisco/XR/packages/
Label : 25.3.1
cisco NCS-560 () processor
System uptime is 1 hour 52 minutes
This table lists the Cisco IOS XR Software feature set matrix (packages) with associated filenames.
Visit the Cisco Software Download page to download the Cisco IOS XR software images.
| Feature Set |
Filename |
Description |
| Cisco IOS XR IP Unicast Routing Core Bundle |
ncs560-mini-x-25.3.1.iso |
Contains base image contents that includes: Host operating system System Admin boot image IOS XR boot image BGP packages OS Admin Base Forwarding Modular Services Card Routing SNMP Agent Alarm Correlation |
| Cisco IOS XR Manageability Package |
ncs560-mgbl-1.0.0.0-r2531.x86_64.rpm |
Telemetry, Extensible Markup Language (XML), Parser, and HTTP server packages, NETCONF, YANG Models, gRPC. |
| Cisco IOS XR OSPF package |
ncs560-ospf-1.0.0.0-r2531.x86_64.rpm |
Supports OSPF |
| Cisco IOS XR Security Package |
ncs560-k9sec-1.0.0.0-r2531.x86_64.rpm |
k9sec is needed for IPsec or MACsec and Dot1x and for basic crypto services such as Decryption, Secure Shell (SSH), Secure Socket Layer (SSL), and Public-key infrastructure (PKI). |
| Multicast Package |
ncs560-mcast-1.0.0.0-r2531.x86_64.rpm |
Supports Multicast Supports Automatic Multicast Tunneling (AMT), IGMP Multicast Listener Discovery (MLD), Multicast Label Distribution Protocol (MLDP), Multicast Source Discovery Protocol (MSDP) and PIM. |
| Cisco IOS XR ISIS package |
ncs560-isis-1.0.0.0-r2531.x86_64.rpm |
Supports Intermediate System to Intermediate System (IS-IS). |
| Cisco IOS XR USB Boot Package |
ncs560-usb_boot-25.3.1.zip |
Supports Cisco IOS XR USB Boot Package |
| Cisco IOS XR MPLS Package |
ncs560-mpls-1.0.0.0-r2531.x86_64.rpm ncs560-mpls-te-rsvp-1.0.0.0-r2531.x86_64.rpm |
Supports MPLS and MPLS Traffic Engineering (MPLS-TE) RPM. Label Distribution Protocol (LDP), MPLS Forwarding, MPLS Operations, Administration, and Maintenance (OAM), Link Manager Protocol (LMP), Optical User Network Interface (OUNI) and Layer-3 VPN. Cisco IOS XR MPLS-TE and RSVP Package MPLS Traffic Engineering (MPLS-TE) and Resource Reservation Protocol (RSVP). |
| Cisco IOS XR LI Package |
ncs560-li-1.0.0.0-r2531.x86_64.rpm |
Lawful Intercept |
| Cisco IOS XR EIGRP Package |
ncs560-eigrp-1.0.0.0-r2531.x86_64.rpm |
(Optional) Includes EIGRP protocol support softwar |
Table 4. Related resources
| Document |
Description |
| An interactive tool that assists in locating features introduced across Cisco IOS XR releases and platforms. |
|
| Information about Smart Licensing Using Policy solutions and their deployment on IOS XR Routers. |
|
| CCO Documentation for Cisco NCS 560 Series Routers |
|
| Search by product family, product ID, data rate, reach, cable type, or form factor to determine the transceivers that Cisco hardware device supports. |
|
| Search by release number, error strings, or compare release numbers to view a detailed repository of error messages and descriptions. |
|
| Select the MIB of your choice from a drop-down to explore an extensive repository of MIB information. |
|
| A user-friendly reference designed to easily explore and understand the various data models supported in Cisco IOS XR platforms and releases. |
|
| Repository containing the folders with yang data models introduced and enhanced in every IOS XR release. |
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