Example for Associating Interface Backup with BFD to Configure an ISDN Interface as the Backup of an Ethernet Interface
Networking Requirements
As shown in Figure 2-21, the egress gateway RouterA in the headquarters of company connects to the IP network through GE1/0/0. The link between GE1/0/0 and the IP network is used as the primary link, and the link between PRI1/0/0:15 (ISDN interface) and the ISDN is used as the backup link.
The company wants to monitor the primary link status within 50 ms. When the primary link is faulty, the backup link is started to transmit services to reduce the impact of the primary link fault on service transmission.
Configuration Roadmap
The configuration roadmap is as follows:
Configure IP addresses for interfaces on routes along the primary link and static routes to ensure connectivity at the network layer.
Configure C-DCC on RouterA and RouterB and configure dialer numbers 600501 and 600502 so that RouterA can initiate calls to and receive calls from RouterB.
Configure BFD sessions on RouterA and RouterB to detect the primary link status.
Associate interface backup with BFD on backup interface PRI1/0/0:15 of RouterA. When the BFD session detects the primary link fault, traffic can be rapidly switched to the backup link.
Procedure
- Implement connectivity at the network layer.
# Assign an IP address to the interface of RouterA.
<Huawei> system-view [Huawei] sysname RouterA [RouterA] interface gigabitethernet1/0/0 [RouterA-GigabitEthernet1/0/0] ip address 2.1.1.1 255.255.255.0 [RouterA-GigabitEthernet1/0/0] quit
# Assign an IP address to the interface of RouterB.
<Huawei> system-view [Huawei] sysname RouterB [RouterB] interface gigabitethernet1/0/0 [RouterB-GigabitEthernet1/0/0] ip address 4.1.1.2 255.255.255.0 [RouterB-GigabitEthernet1/0/0] quit
# Assign an IP address to the interface of RouterC.
<Huawei> system-view [Huawei] sysname RouterC [RouterC] interface gigabitethernet1/0/0 [RouterC-GigabitEthernet1/0/0] ip address 2.1.1.2 255.255.255.0 [RouterC-GigabitEthernet1/0/0] quit
# Assign an IP address to the interface of RouterD.
<Huawei> system-view [Huawei] sysname RouterD [RouterD] interface gigabitethernet1/0/0 [RouterD-GigabitEthernet1/0/0] ip address 4.1.1.1 255.255.255.0 [RouterD-GigabitEthernet1/0/0] quit
# On RouterA, configure a static route to 4.1.1.0/24 of RouterB.
[RouterA] ip route-static 4.1.1.0 255.255.255.0 2.1.1.2 preference 80# On RouterB, configure a static route to 2.1.1.0/24 of RouterA.
[RouterB] ip route-static 2.1.1.0 255.255.255.0 4.1.1.1 preference 80 - Configure C-DCC on RouterA.
# Create dialer group 1 and configure a dialer rule in the group.
[RouterA] dialer-rule [RouterA-dialer-rule] dialer-rule 1 ip permit [RouterA-dialer-rule] quit
# Configure a serial interface.
[RouterA] controller e1 1/0/0 [RouterA-E1 1/0/0] pri-set [RouterA-E1 1/0/0] quit
# Assign an IP address to PRI1/0/0:15, enable C-DCC, and configure the dialer number.
[RouterA] interface serial 1/0/0:15 [RouterA-Serial1/0/0:15] ip address 3.1.1.1 24 [RouterA-Serial1/0/0:15] dialer enable-circular [RouterA-Serial1/0/0:15] dialer-group 1 [RouterA-Serial1/0/0:15] dialer route ip 3.1.1.2 600502 [RouterA-Serial1/0/0:15] quit
# Configure a static route.
[RouterA] ip route-static 3.1.1.0 255.255.255.0 serial 1/0/0:15 preference 60 - Configure C-DCC on RouterB.
# Create dialer group 2 and configure a dialer rule in the group.
[RouterB] dialer-rule [RouterB-dialer-rule] dialer-rule 2 ip permit [RouterB-dialer-rule] quit
# Configure a serial interface.
[RouterB] controller e1 1/0/0 [RouterB-E1 1/0/0] pri-set [RouterB-E1 1/0/0] quit
# Assign an IP address to PRI1/0/0:15, enable C-DCC, and configure the dialer number.
[RouterB] interface serial 1/0/0:15 [RouterB-Serial1/0/0:15] ip address 3.1.1.2 24 [RouterB-Serial1/0/0:15] dialer enable-circular [RouterB-Serial1/0/0:15] dialer-group 2 [RouterB-Serial1/0/0:15] dialer route ip 3.1.1.1 600501 [RouterB-Serial1/0/0:15] quit
# Configure a static route.
[RouterB] ip route-static 3.1.1.0 255.255.255.0 serial 1/0/0:15 preference 60 - Configure BFD sessions between RouterA and RouterB.
# On RouterA, configure a BFD session bound to the destination address 4.1.1.2/24.
[RouterA] bfd [RouterA-bfd] quit [RouterA] bfd test bind peer-ip 4.1.1.2 [RouterA-bfd-session-test] discriminator local 10 [RouterA-bfd-session-test] discriminator remote 100 [RouterA-bfd-session-test] commit [RouterA-bfd-session-test] quit
# On RouterB, configure a BFD session bound to the destination address 2.1.1.1/24.
[RouterB] bfd [RouterB-bfd] quit [RouterB] bfd test bind peer-ip 2.1.1.1 [RouterB-bfd-session-test] discriminator local 100 [RouterB-bfd-session-test] discriminator remote 10 [RouterB-bfd-session-test] commit [RouterB-bfd-session-test] quit
- Configure association between interface backup and BFD on backup interface PRI1/0/0:15.
[RouterA] interface serial 1/0/0:15 [RouterA-Serial1/0/0:15] standby track bfd-session session-name test [RouterA-Serial1/0/0:15] quit
- Verify the configuration.
Run the display bfd session all verbose command on RouterA. The command output shows that the BFD session status is Up.
<RouterA> display bfd session all verbose -------------------------------------------------------------------------------- Session MIndex : 256 (Multi Hop) State :Up Name : test -------------------------------------------------------------------------------- Local Discriminator : 10 Remote Discriminator : 100 Session Detect Mode : Asynchronous Mode Without Echo Function BFD Bind Type : Peer Ip Address Bind Session Type : Static Bind Peer Ip Address : 4.1.1.2 Bind Interface : - FSM Board Id : 0 TOS-EXP : 7 Min Tx Interval (ms) : 1000 Min Rx Interval (ms) : 1000 Actual Tx Interval (ms): 1000 Actual Rx Interval (ms): 1000 Local Detect Multi : 3 Detect Interval (ms) : 3000 Echo Passive : Disable Acl Number : - Destination Port : 3784 TTL : 254 Proc interface status : Disable Process PST : Disable WTR Interval (ms) : - Active Multi : 3 DSCP : - Last Local Diagnostic : No Diagnostic Bind Application : No Application Bind Session TX TmrID : - Session Detect TmrID : - Session Init TmrID : - Session WTR TmrID : - PDT Index : FSM-0|RCV-0|IF-0|TOKEN-0 Session Description : - -------------------------------------------------------------------------------- Total UP/DOWN Session Number : 1/0# View the BFD session status and backup interface status on RouterA. The command output shows that the BFD session status is OK and the status of Serial 1/0/0:15 is STANDBY.
<RouterA> display standby state Interface Interfacestate Backupstate Backupflag Pri Loadstate Backup-flag meaning: M---MAIN B---BACKUP V---MOVED U---USED D---LOAD P---PULLED ---------------------------------------------------------------------------- Below is track BFD information: Bfd-Name Bfd-State BackupInterface State test UP Serial 1/0/0:15 STANDBY ---------------------------------------------------------------------------- Below is track IP route information: Destination/Mask Route-State BackupInterface State -------------------------------------------------------------------------------- Below is track NQA Information: Instance Name BackupInterface StateRun the shutdown command on GE1/0/0 of RouterB to simulate a link fault. Run the display bfd session all verbose command on RouterA. The command output shows that the BFD session status is Down.
<RouterA> display bfd session all verbose -------------------------------------------------------------------------------- Session MIndex : 256 (Multi Hop) State :Down Name : test -------------------------------------------------------------------------------- Local Discriminator : 10 Remote Discriminator : 100 Session Detect Mode : Asynchronous Mode Without Echo Function BFD Bind Type : Peer Ip Address Bind Session Type : Static Bind Peer Ip Address : 4.1.1.2 Bind Interface : - FSM Board Id : 0 TOS-EXP : 7 Min Tx Interval (ms) : 1000 Min Rx Interval (ms) : 1000 Actual Tx Interval (ms): 1000 Actual Rx Interval (ms): 1000 Local Detect Multi : 3 Detect Interval (ms) : 3000 Echo Passive : Disable Acl Number : - Destination Port : 3784 TTL : 254 Proc interface status : Disable Process PST : Disable WTR Interval (ms) : - Active Multi : 3 DSCP : - Last Local Diagnostic : No Diagnostic Bind Application : No Application Bind Session TX TmrID : - Session Detect TmrID : - Session Init TmrID : - Session WTR TmrID : - PDT Index : FSM-0|RCV-0|IF-0|TOKEN-0 Session Description : - -------------------------------------------------------------------------------- Total UP/DOWN Session Number : 0/1Run the display standby state command on RouterA. The command output shows that the BFD session status is ERR, and the status of backup interface Serial 1/0/0:15 is Up, indicating that the backup interface has started.
<RouterA> display standby state Interface Interfacestate Backupstate Backupflag Pri Loadstate Backup-flag meaning: M---MAIN B---BACKUP V---MOVED U---USED D---LOAD P---PULLED ---------------------------------------------------------------------------- Below is track BFD information: Bfd-Name Bfd-State BackupInterface State test ERR Serial 1/0/0:15 UP ---------------------------------------------------------------------------- Below is track IP route information: Destination/Mask Route-State BackupInterface State -------------------------------------------------------------------------------- Below is track NQA Information: Instance Name BackupInterface StateRun the undo shutdown command on GE1/0/0 of RouterB to make the interface Up. Run the display standby state command on RouterA. The command output shows that the BFD session status is OK and backup interface Serial 1/0/0:15 has switched to the standby state.
<RouterA> display standby state Interface Interfacestate Backupstate Backupflag Pri Loadstate Backup-flag meaning: M---MAIN B---BACKUP V---MOVED U---USED D---LOAD P---PULLED ---------------------------------------------------------------------------- Below is track BFD information: Bfd-Name Bfd-State BackupInterface State test UP Serial 1/0/0:15 STANDBY ---------------------------------------------------------------------------- Below is track IP route information: Destination/Mask Route-State BackupInterface State -------------------------------------------------------------------------------- Below is track NQA Information: Instance Name BackupInterface State
Configuration Files
RouterA configuration file
# sysname RouterA # controller E1 1/0/0 pri-set # interface Serial1/0/0:15 link-protocol ppp ip address 3.1.1.1 255.255.255.0 dialer enable-circular dialer-group 1 dialer route ip 3.1.1.2 600502 standby track bfd-session session-name test # dialer-rule dialer-rule 1 ip permit # interface GigabitEthernet1/0/0 ip address 2.1.1.1 255.255.255.0 # ip route-static 4.1.1.0 255.255.255.0 2.1.1.2 preference 80 ip route-static 3.1.1.0 255.255.255.0 Serial 1/0/0:15 # bfd # bfd test bind peer-ip 4.1.1.2 discriminator local 10 discriminator remote 100 commit # return
RouterB configuration file
# sysname RouterB # controller E1 1/0/0 pri-set # interface Serial1/0/0:15 link-protocol ppp ip address 3.1.1.2 255.255.255.0 dialer enable-circular dialer-group 2 dialer route ip 3.1.1.1 600501 # dialer-rule dialer-rule 2 ip permit # interface GigabitEthernet1/0/0 ip address 4.1.1.2 255.255.255.0 # interface Serial 1/0/0:15 ip address 3.1.1.2 255.255.255.0 # ip route-static 2.1.1.0 255.255.255.0 4.1.1.1 preference 80 ip route-static 3.1.1.0 255.255.255.0 Serial 1/0/0:15 # bfd # bfd test bind peer-ip 2.1.1.1 discriminator local 100 discriminator remote 10 commit # return
RouterC configuration file
# sysname RouterC # interface GigabitEthernet1/0/0 ip address 2.1.1.2 255.255.255.0 # return
RouterD configuration file
# sysname RouterD # interface GigabitEthernet1/0/0 ip address 4.1.1.1 255.255.255.0 # return
