DHCPv6 Relay—Reload Persistent Interface ID Option

The DHCPv6 Relay—Reload Persistent Interface ID Option feature makes the interface-ID option persistent. The interface ID option is used by relay agents to decide which interface should be used when forwarding a RELAY-REPLY packet. The interface ID DHCP for IPv6 (DHCPv6) option added to the DHCPv6 relayed message is formed by the interface name concatenated with the VLAN identifier when available. This way the value of the interface-ID option is persistent after a router reload.

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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 at the end of this module.

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Information About DHCPv6 Relay—Reload Persistent Interface ID Option

DHCPv6 Relay—Reload Persistent Interface ID Option Overview

The DHCPv6 Relay—Reload Persistent Interface ID Option feature makes the interface ID option persistent. The interface ID option is used by relay agents to decide which interface should be used when forwarding a RELAY-REPLY packet. A persistent interface ID option does not change if the device acting as a relay agent goes offline (such as during a reload or a power outage). When the device acting as a relay agent returns online, it is possible that changes to the internal interface index of the relay agent may have occurred in certain scenarios (such as cases where the relay agent reboots and has a change in the number of interfaces in the interface index, or the relay agent boots up and has more virtual interfaces than it did before the reboot). This feature prevents this scenario from causing any problems.

This feature changes the DHCPv6 interface ID option to be expressed as simply the short form of the interface name. This short form helps avoid potential problems that could arise due to physical or logical interfaces changing on the relay agent after a reload. No user configuration is required for this feature.

Additional References for DHCPv6 Relay—Reload Persistent Interface ID Option

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Feature Information for DHCPv6 Relay—Reload Persistent Interface ID Option

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 DHCPv6 Relay—Reload Persistent Interface ID Option

Feature Name

Releases

Feature Information

DHCPv6 Relay—Reload Persistent Interface ID Option

Cisco IOS XE Release 3.2SE

The DHCPv6 Relay—Reload Persistent Interface ID Option feature makes the interface-ID option persistent. The interface-ID option is used by relay agents to decide which interface should be used when forwarding a RELAY-REPLY packet.