Release Notes for Cisco Network Convergence System 540 Series Routers


Explore the Content Hub, the all new portal that offers an enhanced product documentation experience.

  • Use faceted search to locate content that is most relevant to you.

  • Create customized PDFs for ready reference.

  • Benefit from context-based recommendations.

Get started with the Content Hub at to craft a personalized documentation experience.

Do provide feedback about your experience with the Content Hub.

Supported Variants

This release notes provide information for the following Cisco NCS 540 Routers:

  • N540-24Z8Q2C-SYS

  • N540X-ACC-SYS

  • N540-ACC-SYS

System Requirements

Cisco IOS XR Release 6.6.3 contains all features that are released in Cisco IOS XR Release 6.6.25.

Cisco IOS XR Release 6.6.25 contains all features that are released in Cisco IOS XR Release 6.6.1. Release 6.6.1 is limited availability (LA) release. For more information on IOS XR Release 6.6.1, see Release Notes for Cisco NCS 540 Series Routers, Release 6.6.1

Release 6.6.3 Packages

This table lists the Cisco IOS XR Software feature set matrix (packages) with associated filenames.

Table 1. Release 6.6.3 Packages for Cisco NCS 540 Series Router

Composite Package

Feature Set



Cisco IOS XR IP Unicast Routing Core Bundle


Contains base image contents that includes:

  • Host operating system

  • System Admin boot image

  • IOS XR boot image

  • BGP packages

Individually Installable Optional Packages

Feature Set



Cisco IOS XR Manageability Package


Extensible Markup Language (XML) Parser, Telemetry, NETCONF, gRPC, and HTTP server packages.

Cisco IOS XR MPLS Package



MPLS and MPLS Traffic Engineering (Cisco Multiprotocol Label Switching Traffic Engineering) RPM.

Cisco IOS XR EIGRP Package


Includes EIGRP protocol support software

Cisco IOS XR Security Package


Support for Encryption, Decryption, Secure Shell (SSH), Secure Socket Layer (SSL), and Public-key infrastructure (PKI)

Cisco IOS XR IS-IS package


Support IS-IS

Cisco IOS XR OSPF package


Support OSPF

Lawful Intercept (LI) Package


Includes LI software images

Multicast Package


Support Multicast

Determine Software Version

To verfiy the software version running on the router, use the show version command in the EXEC mode.

RP/0/RP0/CPU0:R31-NCS540-VIDEO#show version                       
Sat Dec 14 13:14:34.436 IST                                       
Cisco IOS XR Software, Version 6.6.3                              
Copyright (c) 2013-2019 by Cisco Systems, Inc.                    

Build Information:
 Built By     : hlo
 Built On     : Fri Dec 13 16:41:04 PST 2019
 Built Host   : iox-lnx-028                 
 Workspace    : /auto/srcarchive15/prod/6.6.3/ncs540/ws
 Version      : 6.6.3                                  
 Location     : /opt/cisco/XR/packages/                

cisco NCS-540 () processor
System uptime is 18 minutes

Determine Firmware Support

Use the show fpd package command in Admin mode to view the hardware components with their current FPD version and status.

RP/0/RP0/CPU0:R31-NCS540-VIDEO#show fpd package 
Sat Dec 14 13:14:38.526 IST                     

=============================== ================================================
                                        Field Programmable Device Package       
                                               Req     SW      Min Req   Min Req
Card Type            FPD Description           Reload  Ver     SW Ver  Board Ver
=================== ========================== ====== ======= ======== =========
N540-24Z8Q2C-M       Bootloader(A)              YES     1.12    1.12    0.0
                     CPU-IOFPGA(A)              YES     0.03    0.03    0.0
                     MB-IOFPGA(A)               YES     0.20    0.20    0.0
                     MB-MIFPGA                  YES     0.04    0.04    0.0
                     SATA(A)                    NO      5.00    5.00    0.0
N540-ACC-SYS         Bootloader(A)              YES     1.12    1.12    0.0
                     CPU-IOFPGA(A)              YES     0.03    0.03    0.0
                     MB-IOFPGA(A)               YES     0.20    0.20    0.0
                     MB-MIFPGA                  YES     0.04    0.04    0.0
                     SATA(A)                    NO      5.00    5.00    0.0
N540-X-24Z8Q2C-M     Bootloader(A)              YES     1.12    1.12    0.0
                     CPU-IOFPGA(A)              YES     0.03    0.03    0.0
                     MB-IOFPGA(A)               YES     0.20    0.20    0.0
                     MB-MIFPGA                  YES     0.04    0.04    0.0
                     SATA(A)                    NO      5.00    5.00    0.0
N540X-ACC-SYS        Bootloader(A)              YES     1.12    1.12    0.0
                     CPU-IOFPGA(A)              YES     0.03    0.03    0.0
                     MB-IOFPGA(A)               YES     0.20    0.20    0.0
                     MB-MIFPGA                  YES     0.04    0.04    0.0
                     SATA(A)                    NO      5.00    5.00    0.0

Use the show hw-module fpd command in EXEC 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.

RP/0/RP0/CPU0:R31-NCS540-VIDEO#show hw-module fpd
Sat Dec 14 13:14:43.226 IST
                                                               FPD Versions
Location   Card type        HWver FPD device       ATR Status   Running Programd
0/RP0     N540-ACC-SYS      1.0   MB-MIFPGA            CURRENT    0.04    0.04
0/RP0     N540-ACC-SYS      1.0   Bootloader           CURRENT    1.12    1.12
0/RP0     N540-ACC-SYS      1.0   CPU-IOFPGA           CURRENT    0.03    0.03
0/RP0     N540-ACC-SYS      1.0   MB-IOFPGA            CURRENT    0.20    0.20

Supported Software Features

Following are the features that are supported on Cisco IOS XR Release 6.6.3.


Cisco IOS XR Release 6.6.3 features are applicable only to Cisco N540-24Z8Q2C-SYS, N540X-ACC-SYS, and N540-ACC-SYS variants.

Access Pseudowire

The Access Pseudowire feature allows you to reduce the number of pseudowires (PWs) between the network Provider Edge (N-PE) devices. The user Provider Edge (U-PE) device connects to the N- PE device using access pseudowire (PW). This feature prevents signalling overhead and packet replication.

Unlike traditional VPLS where PWs terminate on a physical or logical port, an access PW terminates on N-PE devices. For each VPLS service, create an access PW between U-PEs and N-PEs.

VPLS requires a full mesh of pseudowire (PWs) between L2VPN PEs that participate in the VPLS service. For each VPLS service, PWs must be set up between the PEs. In a full mesh of PWs, the number of PWs increases as the number of PEs increases causing scalability issues. You can decrease the number of PWs with a hierarchy of PEs.

For more information about this feature, see the Configure Multipoint Layer 2 Services chapter in the , IOS XR Release 6.6.x.

DHCPv6 Relay over BVI for IANA Address Allocation

DHCPv6 Relay agents relay all packets that are coming from DHCPv6 clients over the access-interfaces towards external DHCPv6 servers to request IP addresses (::/128) through Internet Assigned Numbers Authority (IANA) allocation for the DHCPv6 clients. DHCPv6 Relay agents also receive response packets from the DHCPv6 servers and forward the packets towards DHCPv6 clients over BVI interfaces. DHCPv6 Relay agents act as stateless, by default, for DHCPv6 clients by not maintaining any DHCPv6 binding and respective route entry for the allocated IP addresses. You can enable a DHCPv6 client to get a particular IPv6 address assigned by the DHCPv6 server over a Bridge Virtual Interface (BVI) through IANA address allocation. Thereby, the DHCPv6 relay agent acts as a stateful relay agent and maintains DHCPv6 binding and respective route entry for the allocated IPv6 addresses.

For more information see the chapter, Implementing the Dynamic Host Configuration Protocol in the

G.8032 Ethernet Ring Protection Support on Layer 2 Bundle Interfaces

The G.8032 Ethernet Ring Protection feature is supported on Layer 2 bundle interfaces. This feature provides protection for Ethernet traffic in a ring topology. This feature prevents loops within the ring at the Ethernet layer by blocking either a predetermined link or a failed link.

For more information about this feature, see the Configure Point-to-Point Layer 2 Services chapter in the , IOS XR Release 6.6.x.

Enhancements to the Multicast Route Statistics

This feature provides information about the IPv4 and IPv6 multicast route statistics. The multicast statistics includes information on the numbers of packets received for a multicast route over an interface in ingress and egress directions.

This feature is already supported in previous releases, however in this release following enhancements are introduced:

  • IPv6 multicast route statistics are supported.

  • Multicast route statistics for egress direction is supported.

For more information oh how to enable multicast route statistics, see Implementing Multicast chapter in

LFA Based FRR and Remote LFA for MLDP

IP Loop Free Alternative FRR is a mechanism that enables a router to rapidly switch traffic to a pre-computed or a pre-programmed loop-free alternative (LFA) path (Data Plane Convergence), following either an adjacent link and node failure, or an adjacent link or node failure in both IP and LDP networks. The LFA path is used to switch traffic till the router installs the new primary next-hops based upon the changed network topology (Control Plane Convergence).

For more information see the chapter, Implementing Layer-3 Multicast Routing in

MPLS VPN support for EIGRP between Provider Edge (PE) and Customer Edge (CE)

The MPLS VPN Support for EIGRP Between PE and CE feature allows service providers to configure the Enhanced Interior Gateway Routing Protocol (EIGRP) between provider edge (PE) and customer edge (CE) devices in a Multiprotocol Label Switching (MPLS) virtual private network (VPN) and offer MPLS VPN services to those customers that require native support for EIGRP. An MPLS VPN consists of a set of sites that are interconnected by an MPLS provider core network. At each customer site, one or more CE devices attach to one or more PE devices.

For more information, see the chapter, Implementing EIGRP in the .

Multicast over Access Pseudo-Wire

Multicast over access PWs allows multicast traffic flooding with MLDP core and PWs that are terminating at CEs. Therefore, connecting two IGMP domains and extending the MVPN traffic via MPLS network terminating at a Layer 3 (VRF or global) domain or a Layer 2 domain using PW.

Multicast over access PWs helps service providers to scale and reduce the hardware cost.

For more information see the chapter, Implementing Multicast in .

Multicast MLDP Profile 14 support on an Edge Router

The MLDP Profile 14 is supported when the router is configured as an edge router.

IP based transport network is a cost efficient and convenient alternative to deliver video services combined with the delivery of other IP based services. To deliver IPTV content MLDP Profile 14 (partitioned MDT) is supported when router is configured as an edge router.

For more information see chapter, Implementing Multicast in

QoS L2 Re-Marking of Ethernet Packets on L3 Flows in Egress Direction

With this release, you now have the ability to perform Layer 2 (802.1p) marking on Layer 3 flows in the egress direction. This allows you to re-mark the priority of Ethernet packets on L3VPN traffic.

For more information, see the section QoS Re-marking of Ethernet Packets in Egress Direction in the .

Rate Limit the Multicast and Broadcast Punted Traffic

This feature enables rate limiting the multicast and broadcast storms of punted traffic at the interface level. Normally, there's no rate limit on multicast and broadcast punted traffic reaching a node. This causes high CPU utilization. In order to protect the CPU from processing storms of multicast and broadcast punted traffic, it's recommended to configure a limit on the multicast and broadcast punted traffic at the interface level.

For more information see the chapter, Implementing LPTS in .

Support for Secondary IP Subnet on BVI

Secondary IP subnet is supported on BVI to enable redundancy and reduce traffic downtime. Also, this feature will enable you to support two different networks over a single interface.

For more information, see the Integrated Routing and Bridging chapter in the .

Unique Policy Map

For more information, see the section Restrictions in the .

Supported Hardware Features

There are no new hardware features introduced in this release.

Supported MIBs

The Cisco NCS 5500 MIB support list is also applicable to the Series Routers. For the list of supported MIBs, see the Cisco NCS5500 MIB Support List.

Restrictions and Limitations on the Cisco NCS 540 Series Router

The following restrictions are applicable only to Cisco N540-24Z8Q2C-SYS, N540X-ACC-SYS, and N540-ACC-SYS variants.

  • In the Cisco IOS XR Release 7.0.1, the Packet IO feature is not supported on bundle interfaces.

  • The show inventory and the show diagnostic commands do not display the fan serial number.

  • The interface ports 0/0/0/24 to 0/0/0/31 do not support 1G Copper SFPs.

  • Remove the speed settings on the 1G Copper optics when 10M/100M is configured and replaced with 1G SFP optics.

  • The hw-module profile mfib statistics command is not supported.


This section describes open and resolved severity 1 and 2 caveats and select severity 3 caveats:

  • The “Open Caveats” sections list open caveats that apply to the current release and may apply to previous releases. A caveat that is open for a prior release and is still unresolved applies to all future releases until it is resolved.

  • The “Resolved Caveats” sections list caveats resolved in a specific release, but open in previous releases.

The bug IDs are sorted alphanumerically.


The Caveats section includes the bug ID and a short description of the bug. For details on the symptoms, conditions, and workaround for a specific caveat you must use the Bug Search Tool.

Cisco IOS XR Caveats Release 6.6.3

Caveat ID Number



"mrib: %ROUTING-MRIB-4-GEN_WARN : Re-pulse client" transient warning message may show at boot up

Upgrading Cisco IOS XR Software

Cisco IOS XR Software is installed and activated from modular packages, allowing specific features or software patches to be installed, upgraded, or downgraded without affecting unrelated processes. Software packages can be upgraded or downgraded on all supported card types, or on a single card (node).

Before starting the software upgrade, use the show install health command in the admin mode. This command validates if the statuses of all relevant parameters of the system are ready for upgrade without interrupting the system.

The upgrade document (NCS540_Upgrade_MOP_6.6.3.pdf) is available along with the software images.

Production Software Maintenance Updates (SMUs)

A production SMU is a SMU that is formally requested, developed, tested, and released. Production SMUs are intended for use in a live network environment and are formally supported by the Cisco TAC and the relevant development teams. Software bugs identified through software recommendations or Bug Search Tools are not a basis for production SMU requests.

For information on production SMU types, refer the Production SMU Types section of the IOS XR Software Maintenance Updates (SMUs) guide.

Communications, Services, and Additional Information

  • To receive timely, relevant information from Cisco, sign up at Cisco Profile Manager.

  • To get the business impact you’re looking for with the technologies that matter, visit Cisco Services.

  • To submit a service request, visit Cisco Support.

  • To discover and browse secure, validated enterprise-class apps, products, solutions and services, visit Cisco Marketplace.

  • To obtain general networking, training, and certification titles, visit Cisco Press.

  • To find warranty information for a specific product or product family, access Cisco Warranty Finder.

Cisco Bug Search Tool

Cisco Bug Search Tool (BST) is a web-based tool that acts as a gateway to the Cisco bug tracking system that maintains a comprehensive list of defects and vulnerabilities in Cisco products and software. BST provides you with detailed defect information about your products and software.