Release Notes for Cisco Resilient Mesh Release 6.2.34

These release notes contain the latest information about using Cisco Resilient Mesh (formerly known as CG-Mesh) with IPv6 Resilient Mesh Endpoints (RMEs) such as meters and the Cisco IR500 Series WPAN Gateway Range Extenders.

Cisco Resilient Mesh is an embedded network stack for Smart Grid assets within a Neighborhood Area Network. Cisco Resilient Mesh provides end-to-end IPv6 communication and implements open-standard protocols at every layer in the network stack, including but not limited to IEEE 802.15.4e/g, 6LoWPAN, IPv6, RPL, UDP, and CoAP. In Smart Grid assets such as residential electric meters, the Cisco Resilient Mesh software functions within a dedicated Communications Module that connects to an Application Module through a PPP link.


When RME is configured in CG-Mesh protocol stack mode, DHCP DUID-LL with hardware type code set to 27 is used in the DHCPv6 client identifier option. Where as in Wi-SUN protocol stack mode, DHCP DUID-LL with hardware type code set to 6 must be used in the DHCPv6 client identifier option, in accordance with the Wi-SUN specification 1.1.


IR529 and IR509 are not supported for CR-Mesh Release 6.2.34 and later releases.


For a detailed description of the Cisco Resilient Mesh software features, refer to Cisco Connected Grid WPAN Module for CGR 1000 Series Installation and Cisco Resilient Mesh Configuration Guide.

New Features for This Release

The following table lists the enhancements specific to this release.

Table 1. Enhancements for Cisco Resilient Mesh Release 6.2.34




Itron meter RME

CoAP draft implementation for backward compatibility

Enables Itron CE to communicate with meters for meter data management. For details, see CSCwd03524.



DHCP server compatibility

Enables CR Mesh to communicate with all versions of CPNR DHCP Servers. For details, see CSCwd18280.

System Requirements

If you plan to run Cisco Resilient Mesh Release 6.2.34, you must have the following required hardware and software components:


Minimum Cisco IOS Software Release Required

Cisco 1000 Series Connected Grid Router

Cisco IOS Release 15.9(3)M4 or later

Cisco Catalyst IR8100 Heavy Duty Series Routers

Cisco IOS-XE Release 17.6.1a or later

Cisco IR530


Cisco IR510


WPAN FSK module


WPAN OFDM module


IoT Field Network Director

Release 4.9.0 or later


Supported Software Features

This section covers the supported software features.

Compromised Node Eviction

A compromised node is one where the device can no longer be trusted by the network and/or operators. Nodes within an IEEE 802.15.4 PAN must possess the currently valid Group Temporal Key (GTK) to send and receive link-layer messages. The GTK is shared among all devices within the PAN and is refreshed periodically or on-demand by communicating new GTKs to only trusted devices, and compromised nodes may be evicted from the network.


In its route-over architecture, Cisco Resilient Mesh performs routing at the network layer using the Routing Protocol for Low-Power and Lossy Networks (RPL).

Cisco Resilient Mesh requires a Cisco 1000 Series Connected Grid Router (CGR) or Cisco Catalyst IR8140 Heavy Duty Router (IR8140H) to provide connectivity to other IPv6 networks. The CGR or IR8140H (Field Area Router (FAR)) must serve as a RPL Directed Acyclic Graph (DAG) root and store information reported in DAO messages to forward datagrams to individual nodes within the mesh network.


The 6LoWPAN adaptation layer adapts IPv6 to operate efficiently over low-power and lossy links such as IEEE 802.15.4. The adaptation layer sits between the IPv6 and IEEE 802.15.4 layers and provides IPv6 header compression, IPv6 datagram fragmentation, and optimized IPv6 Neighbor Discovery.

Frequency Hopping

Cisco Resilient Mesh implements frequency hopping across 64 channels with 400-kHz spacing in the 902 to 928 MHz ISM band. The frequency-hopping protocol used by Cisco Resilient Mesh maximizes the use of the available spectrum by allowing multiple sender-receiver pairs to communicate simultaneously on different channels. The frequency hopping protocol also mitigates the negative effects of narrowband interferers.


For IR510 and IR530 endpoints, high data rates 1.2Mbps with 31 channels are also supported.

FND Configuration

Cisco Resilient Mesh solution is managed and monitored by the Cisco IoT Field Network Director (FND), which provides the necessary backend network configuration, monitoring, event notification services, network stack firmware upgrade, as well as FND outage and meter registration. IoT FND also retrieves statistics on network traffic from the interface.



For more information on the IR8140H router configuration, refer to Cisco Catalyst IR8140 Heavy Duty Series Router Software Configuration Guide.


IR510 and IR530 will be supported only with FND Release 4.1 or greater. Refer to the Cisco IoT Field Network Director User Guides for details.

CoAP Simple Management Protocol

Cisco Resilient Mesh implements the CoAP Simple Management Protocol (CSMP) for remote configuration, monitoring, and event generation over the IPv6 network. The CSMP service is exposed over both the mesh and serial interfaces. For backward compatibility on Itron 30 meters, CSMP service is exposed via both CoAP RFC port (61628) and Draft port (61624). But communication with FND will continue to be on RFC port for all the RMEs.

Power-outage Notification

Cisco Resilient Mesh supports timely and efficient reporting of power outages and restorations.

In the event of a power outage, Cisco Resilient Mesh enters power-outage notification mode and the node stops listening for traffic to conserve energy. Cisco Resilient Mesh triggers functions to conserve energy by notifying the communication module and neighboring nodes of the outage. The outage notification is sent using the same security settings as any other UDP/IPv6 datagram transmission.

In the event of a power restoration, a Cisco Resilient Mesh node sends a restoration notification using the same communication method as the outage notification. The communication modules unaffected by the power outage event deliver the restoration notification.

Registration of Endpoint

You can register and manage Cisco Resilient Mesh Endpoints (RMEs) such as meters using the IoT FND (which uses the CSMP protocol).

Limitations and Restrictions

Cisco recommends that you review this section before you begin working with the module. These are known limitations that will not be fixed, and there is not always a workaround for these issues. Some features might not work as documented, and some features might be affected by recent changes to the router hardware or software.

  • CSCvz38077

    Symptom: Fail to refresh pub key via EST when OFDM WPAN and Itron node are working in PHY mode 2.

    Conditions: This issue occurs when:

    1. CG-mesh stack mode with phymode 2

    2. OFDM WPAN in Release 6.2 + Itron node in Release 5.6 or 6.2

    3. 802.1x certificate length is too long (more than 700 bytes)

    Workaround: Use certificate less than 700 bytes.

  • CSCub49104

    Symptom: Output from show mesh-security session all does not show all current mesh security sessions.

    Conditions: This issue occurs in the output of the show mesh-security session all command.

    Workaround: To find out the mesh-key status of a meter, use the show mesh-security session mac <mac-address> command.

  • CSCvs69721

    Symptom: IR530 will hang if downgrading from 6.2 to 6.0.19 with unsupported phy modes configured.

    Conditions: This issue occurs when IR530 configured with phy mode 1 or 2 is downgraded from 6.2 to 6.0.19 (phy modes 1 and 2 are supported in 6.2 but not supported in 6.0.19).

    Workaround: The workaround is (1) creating a configuration file with supported phy modes in 6.0, or (2) changing phy mode to a supported phy mode in 6.0 before downgrade.


This section addresses the Open and Resolved caveats that are relevant to Cisco Resilient Mesh. This section also provides information on how to use the Bug Tool Kit to find further details on the caveats.

Accessing Bug Search Tool

You can use the Bug Search Tool to find information about caveats for this release, including a description of the problems and available workarounds. The Bug Search Tool lists both open and resolved caveats.

To access Bug Search Tool, you need the following items:

  • Internet connection

  • Web browser

  • user ID and password

To access the Bug Search Tool, enter the following URL:

Feature History


Cisco IOS Release

Feature information

Cisco Resilient Mesh firmware 6.2.34

Cisco IOS Release 15.9(3)M4 or later

Cisco Resilient Mesh enhancement.

Related Documentation

Consult the following resources for related information about the Connected Grid WPAN Module for technical assistance.

Hardware Overview and Installation