Hardware

Support for Cisco N560-4-PWR-FAN-R (Primary) and N560-4-FAN-H-R (Secondary) Reverse Air Flow Fan Modules

This release introduces the following reverse airflow fan modules:

• N560-4-PWR-FAN-R (primary)

• N560-4-FAN-H-R (secondary)

These modules direct airflow from the left side of the router to the right side.

For more information, see the Cisco NCS 560-4 Router Hardware Installation Guide.

System Monitoring

SNMP Dying Gasp for IPv4 and IPv6

You can configure the SNMP agent to generate IPv4 and IPv6 SNMP traps when the router triggers a message to the Network Management System (NMS) that a node is going down. Such a message, known as a dying gasp event, is sent when a power failure occurs or the input power source is disconnected.

Interface and Hardware Component

VLAN Subinterface as Source for Traffic Mirroring

You can now configure the VLAN subinterface as a source for traffic mirroring for:

• Traffic ingressing at the interface

• Traffic egressing at the interface

• Traffic egressing and ingressing at the same interface

You could configure mirror functionality only at the main interface level in earlier releases.

String-based MAID formats for Hardware Offload CFM Sessions

You can now use the Invalid and String format for hardware-offloaded Connectivity Fault Management (CFM) sessions using the Maintenance Association Identifier (MAID) functionality. Earlier releases supported numerical and ICC formats for hardware-offloaded sessions.

The router continues to support 1000 CFM sessions which include 500 hardware offload CFM sessions.

Ethernet Link OAM on Physical Interface— (802.3ah) Link Monitoring and Remote Loopback

Ethernet link OAM operates on a single, physical link and it can be configured to monitor either side or both sides of that link. Ethernet OAM supports:

• Link Monitoring

• Remote Loopback

L2VPN and Ethernet Services

MAC Loop Prevention

This feature helps reduce network congestion and avoid traffic loss by shutting down a port after it reaches the configured number of MAC moves within the specified move interval. You can configure this feature at the bridge-domain level using the mac secure command.

This feature is now supported on routers that operate in native and compatibility modes.

Segment Routing

SRv6: Ultimate Segment Decapsulation (USD) behavior

This feature supports the Ultimate Segment Decapsulation (USD) variant on SRv6 endpoint nodes using full-length SIDs. Previously, USD variant was supported on SRv6 endpoint nodes using using Micro SIDs (uSIDs).

The USD variant enables interworking with SRv6 underlay headend nodes that push SIDs using H.Encaps (SR Headend Behavior with Encapsulation in an SRv6 Policy) or H.Encaps.Red (H.Encaps with reduced Encapsulation) instead of H.Insert (SR Headend with insertion of an SRv6 Policy) or H.Insert.Red (H.Insert with reduced insertion).

The USD variant enables interworking with SRv6 underlay headend nodes that push SIDs using H.Encaps (SR Headend Behavior with Encapsulation in an SRv6 Policy) or H.Encaps.Red (H.Encaps with reduced Encapsulation) instead of H.Insert (SR Headend with insertion of an SRv6 Policy) or H.Insert.Red (H.Insert with reduced insertion).

SRv6 Services: Ethernet VPN Emulated LAN (ELAN)

This feature builds upon EVPN BGP signaling to provide Emulated Local Area Network (ELAN) multipoint-to-multipoint Ethernet services over an SRv6-based network.

This feature introduces the following ELAN-related behaviors:

• Ingress PE:

  • H.Encaps.L2.[Red] – Encapsulation of L2/Ether frame using SRv6

• Egress PE:

  • End.DT2U – Decapsulation and Unicast MAC L2 Table Lookup

  • End.DT2M – Decapsulation and L2 Table Flooding

Flexible Algorithm to Exclude SRLGs for OSPF

You can now configure the flexible algorithm to exclude any link belonging to the Shared Risk Link Groups (SRLGs) from the path computation for OSPF. The ability to exclude the at-risk links ensures that the rest of the links in the network remain unaffected.

Flexible Algorithm Prefix-SID Redistribution for External Route Propagation

This feature enables the propagation of flexible algorithm prefix-SIDs and their algo-specific metric from other domains into OSPF, and from OSPF to other domains.

The show route command has been modified to include additional attributes to indicate the external routes.

Optimal Utilization of ECMP FEC Resources

BGP-SR multipath ECMP FEC optimization is enhanced to support 32k BGP-LU prefixes (from the earlier 4k BGP-LU prefixes) on multipath with the same outgoing label. This results in the consumption of lesser ECMP FEC resources, thus avoiding out-of-resource (OOR) situations for your router.

In earlier releases, all 4k BGP-LU prefixes consumed all the 4k ECMP FEC resources.

Use the hw-module fib mpls bgp-sr lsr-optimized command to enable BGP-SR multipath ECMP FEC optimization.

BGP

BGP-LU Multipath PIC with Auto Protection

BGP-LU multipath prefix independent convergence (PIC) supports auto protection. Each active path has a backup path, ensuring almost immediate restoration of multicast traffic when a path fails.

In earlier releases, path failures led to traffic drops in the absence of auto protection.

Replace BGP AS Path with Custom Values

You can now configure to replace the AS Path in BGP with custom values, based on route policy. While selecting BGP best path, a shorter AS Path makes the selection process simple and flexible.

This feature introduces the following command:

• replace as-path all

RIPng

RIPng (RIP next generation) is a RIPv2 extension that supports IPv6 which is the next-generation Internet Protocol. RIPng provides routing functionalities for an IPv6-based network. RIPng functions as an interior gateway protocol (IGP) in moderate-sized autonomous systems. RIPng uses Bellman-Ford distance-vector algorithm to determine the best route to an IPv6 destination. RIP enhancements for IPv6 include support for IPv6 addresses and prefixes; and the use of the all-RIP-devices multicast group address FF02::9 as the destination address for RIP update messages.

Programmability

New Unified Models

Unified models are CLI-based YANG models that are designed to replace the native schema-based models. This releaes introduces new unified models.

You can access the new unified models from the Github repository.

Modular QoS

Setting MPLS Experimental Bits on Inner MPLS Headers to Classify Traffic

For MPLS over GRE scenarios that tunnel MPLS traffic over non-MPLS networks across CE devices, you can now perform QoS classification for specific traffic or applications by setting MPLS EXP bit field values in the inner MPLS header.

In earlier releases, you could perform QoS classification only in the outer GRE IP header using DiffServ Code Point (DSCP) or IP precedence bits that helped you achieve the required line rate minus the granularity.

Multicast

Flexible Algorithm for Multicast VPN profiles

Flexible Algorithm is now available for the following profiles:

• Profile 12: Default MDT - MLDP - P2MP - BGP-AD - BGP C-Mcast Signaling

• Profile 14: Partitioned MDT - MLDP P2MP - BGP-AD - BGP C-Mcast Signaling