EoGRE: Inter-chassis HA

The EoGRE: Inter-chassis HA feature converts the existing IP session to Dynamic Host Configuration Protocol (DHCP) session upon receiving DHCP control packets requested by the subscriber.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

Information About EoGRE: Inter-Chassis HA

Overview of EoGRE: Inter-Chassis HA

The support for interchassis stateless High Availability (HA) results in an existing DHCP session to appear as unclassified IP session. The subscriber is unaware about the reboot of iWAG on the device and continues to send data packets thereby creating an unclassified IP session. After half lease time, the subscriber may send a unicast renew which removes the existing session and creates a new DHCP session. Therefore it is mandatory to keep the existing session and continue the service to the subscriber unless the subscriber reappears on different service set identifier (SSID) or reboot and send discover packet.

On receiving the DHCP control packets, iWAG validates the packets against any existing unclassified session. If an unclassified session is found, iWAG validates the subnet of both the existing session and the DHCP control packet. If the subnets match, iWAG will update the existing session from unclassified MAC to DHCP session creating a DHCP binding.


Note

In case of any discrepancy, iWAG will bring down the existing unclassified session, discarding the DHCP control packet as well.

EoGRE: Inter-Chassis Stateless HA Call Flow

The following figure and the subsequent steps describes a call flow pertaining to a Ethernet over GRE (EoGRE): intra-chassis stateless HA.

Figure 1. E0GRE: Inter-Chassis Stateless HA Call Flow

  1. IP session is established on iWAG when a subscriber device connects to network through open or secure SSID.

    1a. Session establishment through Open SSID

    1b. Session establishment through Secure SSID

  2. In case of a fail over, session is re-established on the standby iWAG.

    2a. Coverts subscriber from existing IP session to DHCP session.

Additional References for EoGRE: Inter-Chassis HA

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Command List, All Releases

iWAG commands

Cisco IOS Intelligent Wireless Access Gateway Command Reference

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

http://www.cisco.com/cisco/web/support/index.html

Feature Information for EoGRE: Inter-chassis HA

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Table 1. Feature Information for EoGRE: Inter-chassis HA

Feature Name

Releases

Feature Information

EoGRE: Inter-chassis HA

Cisco IOS XE Release 3.16S

The EoGRE: Inter-chassis HA feature converts the existing IP session to Dynamic Host Configuration Protocol (DHCP) session upon receiving DHCP control packets requested by the subscriber.