Release Notes for Cisco NCS 5500 Series Routers, IOS XR Release 25.2.1
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Cisco NCS 5500 Series Routers, IOS XR Release 25.2.1
Cisco NCS 5500 Series Routers, IOS XR Release 25.2.1
Cisco IOS XR Release 25.2.1 is a new feature and hardware release for Cisco NCS 5500 Series routers. Key highlights include increased Layer 2 and Layer 3 overlay scale, telemetry enhancements, DDoS edge protection, EVPN scalability, selective multicast, IS-IS static neighbor, and SRv6 hardware offload. The release also features a new hardware, Cisco 400G QSFP-DD Ultra Long Haul Coherent Optics.
Table 1. New software features for Cisco NCS 5500 Series Routers, Release 25.2.1
| Product Impact |
Feature |
Description |
| System Setup and Software Installation |
||
| Software Reliability |
Hardware MDB profiles for Layer 2 and Layer 3 services overlay scale increased to 32000 |
Introduced in this release on: NCS 5700 fixed port routers, NCS 5700 line cards [Mode: Native] You can now configure hardware MDB profiles for Layer 2 and Layer 3 services over SRv6 services, enabling you to set overlay scales to 32000 in terms of the number of routers and sessions. This release adds the following hardware MDB profiles to the hw-module profile mdb command:
● l2max-srv6
● l2max-se-srv6
● l3max-srv6
● l3max-se-srv6
|
| Telemetry |
||
| Software Reliability
|
Introduced in this release on: NCS 5500 fixed port routers; NCS 5700 fixed port routers; NCS 5500 modular routers (NCS 5500 line cards; NCS 5700 line cards [Mode: Native] You can now enhance network reliability and resource optimization for efficient data collection and analysis by monitoring interface performance and operational status across platforms. This ensures consistent management, proactive troubleshooting, and optimization in multi-vendor environments by using openconfig-interfaces.yang data models. This can be achieved by enabling telemetry to configure specific sensor paths for tracking interface states. |
|
| Application Hosting |
||
| Upgrade |
Introduced in this release on: NCS 5500 fixed port routers; NCS 5700 fixed port routers; NCS 5500 modular routers (NCS 5500 line cards; NCS 5700 line cards [Mode: Native]) You can now enable the router to detect DDoS attacks targeting MPLS traffic using DDoS edge protection. The router analyzes MPLS flows to identify malicious traffic patterns, ensuring the availability and performance of services traversing MPLS networks. |
|
| Interface and Hardware Component |
||
| Hardware Reliability
|
Introduced in this release on: NCS 5500 modular routers (select variants only*) The QDD Optical Line System (OLS) pluggable optical amplifier is now supported on QSFP28 ports. |
|
| L2VPN and Ethernet Services |
||
| Software Reliability
|
Improved scalability and convergence for EVPN single-flow active using ARP pacing |
Introduced in this release on: NCS 5500 fixed port routers; NCS 5700 fixed port routers; NCS 5500 modular routers (NCS 5500 line cards; NCS 5700 line cards [Mode: Native]) You now have the ability to converge 8,000 hosts in less than a second, with bidirectional traffic. This feature enables the network to recover quickly from failures or changes in topology, ensuring continuous service and balanced data transmission. This capability is achieved by optimizing the management of MAC and IP routes through ARP pacing. |
| Software Reliability |
Introduced in this release on: NCS 5500 fixed port routers; NCS 5700 fixed port routers; NCS 5500 modular routers (NCS 5500 line cards; NCS 5700 line cards [Mode: Native]) Selective Multicast with IGMP Proxy addresses the issue of unnecessary flooding of multicast traffic in EVPN fabrics. It ensures multicast traffic is only forwarded to peers with active receivers, optimizing bandwidth usage. |
|
| Routing |
||
| Ease of Setup |
Introduced in this release on: NCS 5500 fixed port routers; NCS 5700 fixed port routers; NCS 5500 modular routers (NCS 5500 line cards; NCS 5700 line cards [Mode: Native]) IS-IS static neighbor allows the advertisement of an IS-IS link without forming an actual IS-IS adjacency. This feature is useful when a link is required in the topology for the controller, but IS-IS is not actively running on the link. |
|
| System Management |
||
| Software Reliability |
Cisco Smart SFP destination MAC address
|
Introduced in this release on: NCS 5500 fixed port routers (*select variant only) We now allow seamless interoperability between Cisco Smart SFPs and third-party devices that require MAC address validation. This capability is achieved by allowing the configuration of a destination MAC address directly on Cisco Smart SFPs. You can configure a specific destination MAC address on Transparent PDH over Packet (tpop) and Channelized SDH over Packet (csop) Smart SFPs enabling Cisco Smart SFPs to ensure that data packets are successfully accepted by the destination device. By default, the destination MAC address on the Cisco smart SFPs is zero. *This feature is supported on:
● NCS-55A2-MOD-SE-S
● NCS-55A2-MOD-HD-S
|
| Segment Routing |
||
| Software Reliability |
Introduced in this release on: NCS 5500 fixed port routers; NCS 5500 modular routers (NCS 5500 line cards) You can now offload SRv6 liveness monitoring for performance measurement to the router’s hardware, which is the Network Processing Unit (NPU). This hardware-based approach improves efficiency and scalability, helping you meet delay-sensitive Service Level Agreements (SLAs). Previously, this monitoring was handled in software. Using hardware to offload performance monitoring tasks improves efficiency and reduce the load on the main processor. You can enable by using the existing npu-offload under the performance-measurement liveness-profile name liveness profile command. |
|
| API Experience |
Introduced in this release on: NCS 5500 fixed port routers; NCS 5700 fixed port routers; NCS 5500 modular routers (NCS 5500 line cards; NCS 5700 line cards [Mode: Native]) This gRPC-based API exports BGP-LS topology objects, which include Nodes, Links, IPv4 and IPv6 Prefixes, SRv6 SIDs, and SR Policy Candidate Paths. The API is designed to provide real-time updates to external controllers and applications, enabling them to perform tasks such as re-optimization, service placement, and network visualization. For more information, refer to the Cisco Crosswork Optimization Engine User Guides. |
|
Table 2. New hardware for Cisco NCS 5500 Series Routers, Release 25.2.1
| Hardware |
Description |
| Optics |
This release launches the following new optics on selective hardware within the product portfolio. For details, refer to the Transceiver Module Group (TMG) Compatibility Matrix. Cisco 400G QSFP-DD Ultra Long Haul Coherent Optics |
● Autoroute announce with IPv6 destination address for ISIS: Two new keywords, destination and ipv6, were added to the autoroute announce command to provide the IPv6 destination address to ISIS thus allowing an MPLS-TE tunnel as the nexthop for IPv6 destinations. ISIS uses this address when filtering prefixes.
● Customize docker run options using application manager: The --cap-add=NET_RAW option has been added to the docker run configuration which enables application manager containers to perform advanced network-level operations, improving the functionality of containerized applications.
● 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: 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.
● When performing a statistics collection via gNMI from the router for Cisco-IOS-XR-platforms-ofa-oper:ofa/stats/nodes/node/Cisco-IOS-XR-ofa-npu-stats-oper:asic-statistics/asic-statistics-drop-for-npu-ids/asic-statistics-drop-for-npu-id, the precision is incorrectly reported in microseconds instead of nanoseconds.
● Full overwrite for gNMI union-replace operations: The gNMI union-replace operation has been enhanced to align more closely with the intended behavior defined in the gNMI specification. Instead of merging new configuration data with existing configuration, the operation now performs a full commit-replace, ensuring that the resulting configuration reflects only the contents of the union-replace request.
● 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 caveats in this release.
● The Cisco NCS 5500 series modular routers with Cisco NCS 5700 line cards no longer support new features in compatibility mode. All Cisco IOS XR releases will continue to support features that were already enabled in compatibility mode until release 25.1.1. However, no new features will be added to compatibility mode. To take advantage of new features in current and subsequent releases, enable native mode by using the hw-module profile npu native-mode-enable command.
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 EPNM and Crosswork with Cisco IOS XR Software
| Cisco IOS XR |
Crosswork |
EPNM |
| Release 25.2.1 |
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 25.2.1
Copyright (c) 2013-2025 by Cisco Systems, Inc.
Build Information:
Built By : swtools
Built On : Mon Jun 16 07:24:26 PDT 2025
Built Host : iox-lnx-049
Workspace : /auto/srcarchive11/prod/25.2.1/ncs5500/ws
Version : 25.2.1
Location : /opt/cisco/XR/packages/
Label : 25.2.1-iso
cisco NCS-5500 () processor
System uptime is 9 hours 51 minutes
The following tables 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.
Table 4. Supported software for NCS 5500 Series Routers, Release 25.2.1
| Feature Set |
Filename |
Description |
| Composite Package |
||
| Cisco IOS XR IP Unicast Routing Core Bundle |
ncs5500-mini-x.iso |
Contains base image contents that includes: Host operating system System Admin boot image IOS XR boot image BGP packages |
| Individually-Installable Optional Packages |
||
| Cisco IOS XR Manageability Package |
ncs5500-mgbl-3.0.0.0-r2521.x86_64.rpm |
Extensible Markup Language (XML) Parser, Telemetry, Netconf, gRPC and HTTP server packages. |
| Cisco IOS XR MPLS Package |
ncs5500-mpls-2.1.0.0-r2521.x86_64.rpm ncs5500-mpls-te-rsvp-2.2.0.0-r2521.x86_64.rpm |
MPLS and MPLS Traffic Engineering (MPLS-TE) RPM. |
| Cisco IOS XR Security Package |
ncs5500-k9sec-3.1.0.0-r2521.x86_64.rpm |
Support for Encryption, Decryption, Secure Shell (SSH), Secure Socket Layer (SSL), and Public-key infrastructure (PKI) |
| Cisco IOS XR ISIS package |
ncs5500-isis-1.2.0.0-r2521.x86_64.rpm |
Support ISIS |
| Cisco IOS XR OSPF package |
ncs5500-ospf-2.0.0.0-r2521.x86_64.rpm |
Support OSPF |
| Lawful Intercept (LI) Package |
ncs5500-li-1.0.0.0-r2521.x86_64.rpm |
Includes LI software images |
| Multicast Package |
ncs5500-mcast-1.0.0.0-r2521.x86_64rpm |
Support Multicast |
| EIGRP |
ncs5500-eigrp-1.0.0.0-r2521.x86_64.rpm |
Supports Enhanced Interior Gateway Routing Protocol |
| Lawful Intercept Control |
ncs5500-lictrl-1.0.0.0-r2521x86_64.rpm |
Supports Lawful Intercept Control |
| Healthcheck |
ncs5500-healthcheck-1.0.0.0-r2521.x86_64.rpm |
Supports System Health Check |
Table 5. TAR files for Cisco NCS 5500 Series Router, Release 25.2.1
| Feature Set |
Filename |
| NCS 5500 IOS XR Software 3DES |
NCS5500-iosxr-k9-25.2.1.tar |
| NCS 5500 IOS XR Software |
NCS5500-iosxr-25.2.1.tar |
| NCS 5500 IOS XR Software |
NCS5500-docs-25.2.1.tar |
| NCS 5500 IOS XR Software 3DES |
NCS5500-iosxr-k9-25.2.1.tar |
| NCS 5500 IOS XR Software |
NCS5500-iosxr-25.2.1.tar |
Table 6. Packages for Cisco NCS 5700 Series Router, Release 25.2.1
| Feature Set |
Filename |
| NCS 5700 IOS XR Software |
ncs5700-x64-25.2.1.iso |
| NCS 5700 IOS XR Software (only k9 RPMs) |
ncs5700-k9sec-rpms.25.2.1.tar |
| NCS 5700 IOS XR Software Optional Package |
NCS5700-optional-rpms.25.2.1.tar This TAR file contains the following RPMS: optional-rpms/cdp/* optional-rpms/eigrp/* optional-rpms/telnet/* |
Table 7. Related resources
| Resource |
Description |
| Assists in locating features introduced across Cisco IOS XR releases and platforms. |
|
| Provides information about Smart Licensing Using Policy solutions and their deployment on IOS XR routers. |
|
| Provides CDC documentation for Cisco NCS 5500 series routers. |
|
| Allows searching by product family, product ID, data rate, reach, cable type, or form factor to determine the transceivers that Cisco hardware device supports. |
|
| Allows searching by release number, error strings, or comparing release numbers to view a detailed repository of error messages and descriptions. |
|
| Allows selecting the MIB of your choice from a drop-down to explore an extensive repository of MIB information. |
|
| Provides yang data models introduced and enhanced in every IOS XR release. |
|
| Provides a general guide in case of upgrading IOS XR routers or new deployments that involve IOS XR routers. |
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