Example for Configuring a BFD for Link-Bundle Session to Detect Layer 3 Eth-Trunk Member Link Faults (IPv6)
This section provides an example for configuring a BFD for link-bundle session to monitor Layer 3 Eth-Trunk member links and rapidly detect link faults in an IPv6 scenario.
Networking Requirements
On the network shown in Figure 1, DeviceA and DeviceB are directly connected through Layer 3 Eth-Trunk interfaces. BFD sessions can be bound to Eth-Trunk interfaces to detect the connectivity of the Eth-Trunk between DeviceA and DeviceB. If single-hop BFD sessions are used, BFD selects one of the Eth-Trunk member links to monitor the state of the Eth-Trunk. Once BFD detects that the selected member link is down, it assumes the Eth-Trunk is down even if the other member links of the Eth-Trunk are up. To prevent BFD from incorrectly identifying the Eth-Trunk state, deploy BFD for link-bundle sessions instead of single-hop BFD sessions.
Configuration Roadmap
The configuration roadmap is as follows:
Create an Eth-Trunk interface on DeviceA and DeviceB, and then add Ethernet physical interfaces to each Eth-Trunk interface.
- Assign IPv6 addresses to the Eth-Trunk interfaces on DeviceA and DeviceB to enable the devices to interwork with each other through the Eth-Trunk interfaces.
Configure a BFD for link-bundle session on DeviceA and DeviceB to monitor the Eth-Trunk member links between them.
The IPv6 addresses configured for Eth-Trunk interfaces can be global or link-local addresses. If global addresses are used, BFD for link-bundle cannot share a session with BFD for IGP. However, if link-local addresses are used, BFD for link-bundle can share a session with BFD for IGP. In this example, global addresses are used.
Data Preparation
To complete the configuration, you need the following data:
IDs of the physical interfaces connecting DeviceA and DeviceB
IPv6 addresses of the Eth-Trunk interfaces
The minimum interval at which BFD for link-bundle session packets are received
Procedure
- Create an Eth-Trunk interface on DeviceA and DeviceB, and then add Ethernet physical interfaces to each Eth-Trunk interface.
# Configure DeviceA. The configuration of DeviceB is similar to the configuration of DeviceA. For configuration details, see Configuration Files in this section.
<HUAWEI> system-view [~HUAWEI] sysname DeviceA [*HUAWEI] commit [~DeviceA] interface Eth-Trunk 1 [*DeviceA-Eth-Trunk1] commit [~DeviceA-Eth-Trunk1] quit [~DeviceA] interface gigabitethernet0/1/16 [~DeviceA-Gigabitethernet0/1/16] undo shutdown [*DeviceA-Gigabitethernet0/1/16] eth-trunk 1 [*DeviceA-Gigabitethernet0/1/16] commit [~DeviceA-Gigabitethernet0/1/16] quit [~DeviceA] interface gigabitethernet0/1/17 [~DeviceA-Gigabitethernet0/1/17] undo shutdown [*DeviceA-Gigabitethernet0/1/17] eth-trunk 1 [*DeviceA-Gigabitethernet0/1/17] commit [~DeviceA-Gigabitethernet0/1/17] quit
- Assign IPv6 addresses to the Eth-Trunk interfaces on DeviceA and DeviceB to enable the devices to interwork with each other through the Eth-Trunk interfaces.
# Configure DeviceA. The configuration of DeviceB is similar to the configuration of DeviceA. For configuration details, see Configuration Files in this section.
[~DeviceA] interface Eth-Trunk 1 [~DeviceA-Eth-Trunk1] ipv6 enable [~DeviceA-Eth-Trunk1] ipv6 address 2001:DB8:1::1 64 [*DeviceA-Eth-Trunk1] commit [~DeviceA-Eth-Trunk1] quit
After the configuration is complete, Eth-Trunk 1 on DeviceA and DeviceB can ping each other.
The following example uses the command output on DeviceB.
[~DeviceB] ping ipv6 2001:DB8:1::1 PING 2001:DB8:1::1 56 data bytes, press CTRL_C to break Reply from 2001:DB8:1::1: bytes=56 Sequence=1 ttl=255 time=10 ms Reply from 2001:DB8:1::1: bytes=56 Sequence=2 ttl=255 time=2 ms Reply from 2001:DB8:1::1: bytes=56 Sequence=3 ttl=255 time=2 ms Reply from 2001:DB8:1::1: bytes=56 Sequence=4 ttl=255 time=1 ms Reply from 2001:DB8:1::1: bytes=56 Sequence=5 ttl=255 time=2 ms --- 2001:DB8:1::1 ping statistics --- 5 packet(s) transmitted 5 packet(s) received 0.00% packet loss round-trip min/avg/max = 1/3/10 ms
- Configure a BFD for link-bundle session on DeviceA and DeviceB to monitor the Eth-Trunk member links between them.
# Configure DeviceA.
[~DeviceA] bfd [*DeviceA-bfd] quit [*DeviceA] bfd atob bind link-bundle peer-ipv6 2001:DB8:1::2 interface Eth-Trunk 1 source-ipv6 2001:DB8:1::1 [*DeviceA-bfd-session-atob] min-rx-interval 10 [*DeviceA-bfd-session-atob] min-tx-interval 10 [*DeviceA-bfd-session-atob] commit [~DeviceA-bfd-session-atob] quit
# Configure DeviceB.
[~DeviceB] bfd [*DeviceB-bfd] quit [*DeviceB] bfd btoa bind link-bundle peer-ipv6 2001:DB8:1::1 interface Eth-Trunk 1 source-ipv6 2001:DB8:1::2 [*DeviceB-bfd-session-btoa] min-rx-interval 10 [*DeviceB-bfd-session-btoa] min-tx-interval 10 [*DeviceB-bfd-session-btoa] commit [~DeviceB-bfd-session-btoa] quit
- Verify the configuration.
# After completing the configuration, run the display bfd link-bundle session command on DeviceA. The command output shows that three BFD sessions have been established and are in the Up state. The discriminators of the three BFD sessions are dynamically allocated by the system. The BFD session bound to Eth-Trunk 1 is the main session, and the other two are BFD sub-sessions bound to GE 0/1/16 and GE 0/1/17, respectively.
[DeviceA] display bfd link-bundle session Total Up/Down Main Session Number : 1/0 Total Up/Down Sub Session Number : 2/0 -------------------------------------------------------------------------------- Name : atob State : Up Local Discriminator : 1048576 Remote Discriminator : - Session Detect Mode : Asynchronous Mode Without Echo Function BFD Bind Type : Interface(Eth-Trunk1) Bind Session Type : Static_Auto(Bundle_Main | Compatible) Bind Peer IP Address : 2001:DB8:1::2 Bind Source IP Address : 2001:DB8:1::1 FSM Board Id : - TOS-EXP : 7 Min Tx Interval (ms) : 10 Min Rx Interval (ms) : 10 Local Detect Multi : 3 WTR Interval (ms) : - Last Local Diagnostic : Control Detection Time Expired Bind Application : AUTO Sub Session Count : 2 -------------------------------------------------------------------------------- Sub Session Number : 1 State : Up Local Discriminator : 16385 Remote Discriminator : 16385 BFD Bind Type : Interface(GigabitEthernet0/1/16) Bind Session Type : Dynamic(Bundle_Sub | Compatible) FSM Board Id : 9 Min Tx Interval (ms) : 10 Min Rx Interval (ms) : 10 Local Detect Multi : 3 Actual Tx Interval (ms): 10 Actual Rx Interval (ms): 10 Active Multi : 3 Detect Interval (ms) : 30 Destination Port : 6784 Last Local Diagnostic : Control Detection Time Expired -------------------------------------------------------------------------------- Sub Session Number : 2 State : Up Local Discriminator : 16386 Remote Discriminator : 16386 BFD Bind Type : Interface(GigabitEthernet0/1/17) Bind Session Type : Dynamic(Bundle_Sub | Compatible) FSM Board Id : 9 Min Tx Interval (ms) : 10 Min Rx Interval (ms) : 10 Local Detect Multi : 3 Actual Tx Interval (ms): 10 Actual Rx Interval (ms): 10 Active Multi : 3 Detect Interval (ms) : 30 Destination Port : 3784 Last Local Diagnostic : Control Detection Time Expired --------------------------------------------------------------------------------
# Shut down GE 0/1/16 on DeviceA.
[~DeviceA] interface gigabitethernet0/1/16 [~DeviceA-Gigabitethernet0/1/16] shutdown [*A-Gigabitethernet0/1/16] commit [~DeviceA-Gigabitethernet0/1/16] quit
# Run the display bfd session all command on DeviceA to view the states of the BFD sessions. The command output shows that the BFD sub-session bound to GE 0/1/16 is in the Down state and the BFD main session bound to Eth-Trunk 1 is still in the Up state.
[DeviceA] display bfd session all S: Static session D: Dynamic session IP: IP session IF: Single-hop session PEER: Multi-hop session AUTO: Automatically negotiated session (w): State in WTR (*): State is invalid Total UP/DOWN Session Number : 2/1 -------------------------------------------------------------------------------- Local Remote PeerIpAddr State Type InterfaceName -------------------------------------------------------------------------------- 1048576 - 2001:DB8:1::1 Up S/AUTO-IF Eth-Trunk1 16386 0 2001:DB8:1::1 Down D/IP-IF Gigabitethernet0/1/16 16387 16387 2001:DB8:1::1 Up D/IP-IF Gigabitethernet0/1/17 --------------------------------------------------------------------------------
# Shut down GE 0/1/17, and run the display bfd session all command on DeviceA. The command output shows that all three BFD sessions are in the Down state.
[DeviceA] display bfd session all S: Static session D: Dynamic session IP: IP session IF: Single-hop session PEER: Multi-hop session AUTO: Automatically negotiated session (w): State in WTR (*): State is invalid Total UP/DOWN Session Number : 0/3 -------------------------------------------------------------------------------- Local Remote PeerIpAddr State Type InterfaceName -------------------------------------------------------------------------------- 1048576 2001:DB8:1::2 Down D/AUTO-IF Eth-Trunk1 16386 0 2001:DB8:1::2 Down D/IP-IF Gigabitethernet0/1/16 16387 - 2001:DB8:1::2 Down A/IP-IF Gigabitethernet0/1/17 --------------------------------------------------------------------------------
Configuration Files
DeviceA configuration file
# sysname DeviceA # interface Eth-Trunk1 ipv6 enable ipv6 address 2001:DB8:1::1 64 # interface Gigabitethernet0/1/16 undo shutdown eth-trunk 1 # interface Gigabitethernet0/1/17 undo shutdown eth-trunk 1 # bfd # bfd atob bind link-bundle peer-ipv6 2001:DB8:1::2 interface Eth-Trunk1 source-ipv6 2001:DB8:1::1 min-tx-interval 10 min-rx-interval 10 # return
DeviceB configuration file
# sysname DeviceB # interface Eth-Trunk1 ipv6 enable ipv6 address 2001:DB8:1::2 64 # interface Gigabitethernet0/1/16 undo shutdown eth-trunk 1 # interface Gigabitethernet0/1/17 undo shutdown eth-trunk 1 # bfd # bfd btoa bind link-bundle peer-ipv6 2001:DB8:1::1 interface Eth-Trunk1 source-ipv6 2001:DB8:1::2 min-tx-interval 10 min-rx-interval 10 # return