IPv6 Configuration Guide, Cisco IOS Release 15.2M&T
IPv6 Support on BVI Interfaces
IPv6 Support on BVI Interfaces
Last Updated: July 31, 2012
Integrated routing and bridging (IRB) enables users to route a given protocol between routed interfaces and bridge groups or route a given protocol between bridge groups. IPv6 is supported in the bridge virtual interface (BVI), which is the IPv4 interface for bridged interfaces. This feature allows IPv6 commands to be supported on the BVI so that users can assign IPv6 addresses to a BVI and route IPv6 packets.
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 at the end of this module.
Restrictions for IPv6 Support on BVI Interfaces
Information About IPv6 Support on BVI Interfaces
IPv6 on BVI Interfaces for Bridging and Routing
Integrated routing and bridging (IRB) enables users to route a given protocol between routed interfaces and bridge groups or route a given protocol between bridge groups. Specifically, local or unroutable traffic will be bridged among the bridged interfaces in the same bridge group, while routable traffic will be routed to other routed interfaces or bridge groups. If you want both bridging and routing capabilities, IRB is required. If you want only bridging, you must disable routing. To disable the routing function for IPv6, you must configure the no ipv6 unicast-routing command.
IPv6 is supported in the bridge virtual interface (BVI), which is the IPv4 interface for bridged interfaces. Because bridging is in the data link layer and routing is in the network layer, they have different protocol configuration models to follow. In the basic IPv4 model, for example, all bridged interfaces should belong to the same network, while each routed interface represents a distinct network. Routed traffic is destined for the device, while bridged traffic is never destined for the device. Using BVI avoids the confusion of which protocol configuration model to use when both bridging and routing a given protocol in the same bridge group.
Feature Information for IPv6 Support on BVI Interfaces
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.
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