When Bidirectional Forwarding Detection (BFD) support is configured with Intermediate System To Intermediate System (IS-IS) as a registered protocol with BFD, IS-IS receives forwarding path detection failure messages from BFD.
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Prerequisites for IS-IS IPv6 Client for BFD
IS-IS must be running on all participating devices.
The baseline parameters for BFD sessions must be configured on the interfaces that run BFD sessions to BFD neighbors.
Information About IS-IS IPv6 Client for BFD
IS-IS BFD Topology
When BFD support is configured with IS-IS as a registered protocol with BFD, IS-IS receives forwarding path detection failure messages from BFD. BFD support for IS-IS can be configured in either router address-family configuration mode or interface configuration mode. IS-IS IPv6 can run in single-topology or in Multi-Topology (MT) mode.
IS-IS BFD supports both IPv4 and IPv6 on the same adjacency for single-topology or multi-topology mode. If BFD is enabled for both IPv4 and IPv6, IS-IS sends two BFD session creation requests to BFD. For single-topology mode, the IS-IS adjacency state can only be UP if both BFD sessions are UP. If either of the BFD sessions is DOWN, the associated IS-IS adjacency state is also DOWN. For MT mode, the IS-IS adjacency state can be UP as long as one of topologies has a BFD session in an UP state.
IS-IS BFD IPv6 Session Creation
IS-IS requests a BFD session for the interface and IPv6 address of the neighboring device when all of the following conditions are met:
An IS-IS adjacency entry exists.
The Address Family Identifier (AFI) specific peer interface address is known.
IS-IS BFD is enabled for that AFI on an interface.
IS-IS is enabled for that AFI on the local interface.
If the neighboring device supports RFC 6213, BFD must be enabled for the specified Multi-Topology Identifier (MTID) or Network Layer Protocol Identifier (NLPID).
IS-IS BFD IPv6 Session Deletion
When IS-IS BFD IPv6 is disabled on an interface, IS-IS removes related BFD sessions for IPv6 from the adjacent device. When the IS-IS adjacency entry is deleted, all BFD sessions are also deleted. IS-IS requests BFD to remove each BFD session that it has requested when any of the following events occur:
The IS-IS instance is deleted or un-configured.
The IS-IS adjacency entry is deleted.
IS-IS BFD is disabled on the next hop interface for an address-family.
The neighboring device supports RFC 6213 and indicates that it no longer supports BFD for the specified MTID or NLPID.
Cisco IOS IP Routing: Protocol-Independent Command Reference
Configuring and monitoring IS-IS
“Configuring Integrated IS-IS” module of the
IP Routing Protocols Configuration Guide
Cisco IOS IPv6 features
Cisco IOS IPv6 Feature Mapping
Cisco IOS IPv6 Command Reference
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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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Table 1 Feature Information for IS-IS IPv6 Client for BFD
IS-IS IPv6 Client for BFD
When BFD support is configured with IS-IS as a registered protocol with BFD, IS-IS receives forwarding path detection failure messages from BFD.
The following commands were introduced or modified:
isis ipv6 bfd.