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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.
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.
Only one IS-IS IPv6 session is supported.
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.
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).
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.
| Command or Action | Purpose | |
|---|---|---|
| Step 1 |
enable Example: |
Enables privileged EXEC mode.
|
| Step 2 |
configure terminal Example: |
Enters global configuration mode. |
| Step 3 |
interface type number Example: |
Enters interface configuration mode. |
| Step 4 |
ipv6 address ipv6-address/mask Example: |
Configures IPv6. |
| Step 5 |
isis ipv6 bfd Example: |
Enables IPv6 BFD on a specific interface that is configured for IS-IS. |
| Step 6 |
end Example: |
Exits interface configuration mode and returns to privileged EXEC mode. |
| Command or Action | Purpose | |
|---|---|---|
| Step 1 |
enable Example: |
Enables privileged EXEC mode.
|
| Step 2 |
configure terminal Example: |
Enters global configuration mode. |
| Step 3 |
router isis Example: |
Enables the IS-IS routing protocol and enters router configuration mode. |
| Step 4 |
metric-style wide Example: |
(Optional) Configures a device that is running IS-IS so that it generates and accepts only new-style type, length, value objects (TLVs). |
| Step 5 |
address-family ipv6 Example: |
Enters address family configuration mode for configuring IS-IS routing sessions that use standard IPv6 address prefixes. |
| Step 6 |
multi-topology Example: |
(Optional) Enables multi-topology IS-IS for IPv6. |
| Step 7 |
bfd all-interfaces Example: |
Enables BFD for all interfaces participating in the routing process. |
| Step 8 |
end Example: |
Exits address family configuration mode and returns to privileged EXEC mode. |
Device> enable
Device# configure terminal
Device(config)# interface gigabitethernet 6/0/0
Device(config-if)# ipv6 address 19:111:112::2/64
Device(config-if)# isis ipv6 bfd
Device(config-if)# end
Device> enable
Device# configure terminal
Device(config)# interface gigabitethernet 6/0
Device(config-if)# ipv6 address 19:111:112::1/64
Device(config-if)# isis ipv6 bfd
Device(config-if)# end
Device> enable
Device# configure terminal
Device(config)# router isis
Device(config-router)# metric-style wide
Device(config-router)# address-family ipv6
Device(config-router-af)# multi-topology
Device(config-router-af)# bfd all-interfaces
Device(config-router-af)# end
The following is a sample configuration where interface 0/0/7 of Router A is connected to interface 0/4/6 of router B.
bfd-template single-hop BFDM
interval min-tx 50 min-rx 50 multiplier 3
!
interface TenGigabitEthernet0/0/7
ipv6 address 19:1:1::1/64
ipv6 router isis
bfd template BFDM
isis ipv6 bfd
!
router isis
net 49.0001.1720.1600.1001.00
!
Router B
bfd-template single-hop BFDM
interval min-tx 50 min-rx 50 multiplier 3
!
interface TenGigabitEthernet0/4/6
ipv6 address 19:1:1::2/64
ipv6 router isis
bfd template BFDM
isis ipv6 bfd
!
router isis
net 49.0000.0000.0002.00
!
!
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