配置VRRP与BFD联动实现快速切换
组网需求
如图1所示,局域网内的主机通过Switch双归属到部署了VRRP备份组的RouterA和RouterB,其中RouterA为Master。
用户希望当RouterA或RouterA到Switch间链路出现故障时,主备网关间的切换时间小于1秒,以减少故障对业务传输的影响。
配置思路
采用VRRP与BFD联动实现主备网关间的快速切换,配置思路如下:
- 配置各设备接口IP地址及路由协议,使网络层路由可达。
- 在RouterA和RouterB上配置VRRP备份组,其中RouterA的优先级为120,抢占延时为20秒,作为Master设备;RouterB的优先级为缺省值,作为Backup设备,实现网关的主备备份。
- 在RouterA和RouterB上配置静态BFD会话,监测备份组之间的链路。
- 在RouterB上配置VRRP与BFD联动,实现链路故障时VRRP备份组快速切换。
操作步骤
- 配置设备间的网络互连
# 配置设备各接口的IP地址和路由协议,以RouterA为例。RouterB的配置与RouterA类似,详见配置文件。
<Huawei> system-view [Huawei] sysname RouterA [RouterA] interface gigabitethernet 2/0/0 [RouterA-GigabitEthernet2/0/0] ip address 10.1.1.1 24 [RouterA-GigabitEthernet2/0/0] quit [RouterA] ospf [RouterA-ospf-1] area 0 [RouterA-ospf-1-area-0.0.0.0] network 10.1.1.0 0.0.0.255 [RouterA-ospf-1-area-0.0.0.0] quit [RouterA-ospf-1] quit
- 配置VRRP备份组
# 在RouterA上创建VRRP备份组1,配置RouterA在该备份组中的优先级为120,并配置抢占延时为20秒。
[RouterA] interface gigabitethernet 2/0/0 [RouterA-GigabitEthernet2/0/0] vrrp vrid 1 virtual-ip 10.1.1.3 [RouterA-GigabitEthernet2/0/0] vrrp vrid 1 priority 120 [RouterA-GigabitEthernet2/0/0] vrrp vrid 1 preempt-mode timer delay 20 [RouterA-GigabitEthernet2/0/0] quit
# 在RouterB上创建VRRP备份组1,其在该备份组中的优先级为缺省值100。
[RouterB] interface gigabitethernet 2/0/0 [RouterB-GigabitEthernet2/0/0] vrrp vrid 1 virtual-ip 10.1.1.3 [RouterB-GigabitEthernet2/0/0] quit
- 配置静态BFD会话
# 在RouterA上配置BFD会话。
[RouterA] bfd [RouterA-bfd] quit [RouterA] bfd atob bind peer-ip 10.1.1.2 interface gigabitethernet 2/0/0 [RouterA-bfd-session-atob] discriminator local 1 [RouterA-bfd-session-atob] discriminator remote 2 [RouterA-bfd-session-atob] min-rx-interval 50 [RouterA-bfd-session-atob] min-tx-interval 50 [RouterA-bfd-session-atob] commit [RouterA-bfd-session-atob] quit
# 在RouterB上配置BFD会话。
[RouterB] bfd [RouterB-bfd] quit [RouterB] bfd btoa bind peer-ip 10.1.1.1 interface gigabitethernet 2/0/0 [RouterB-bfd-session-btoa] discriminator local 2 [RouterB-bfd-session-btoa] discriminator remote 1 [RouterB-bfd-session-btoa] min-rx-interval 50 [RouterB-bfd-session-btoa] min-tx-interval 50 [RouterB-bfd-session-btoa] commit [RouterB-bfd-session-btoa] quit
配置完成后,在RouterA或RouterB上执行display bfd session命令,可以看到BFD会话的状态为Up。以RouterA的显示为例。
[RouterA] display bfd session all -------------------------------------------------------------------------------- Local Remote PeerIpAddr State Type InterfaceName -------------------------------------------------------------------------------- 1 2 10.1.1.2 Up S_IP_IF GigabitEthernet1/0/0 -------------------------------------------------------------------------------- Total UP/DOWN Session Number : 1/0
- 配置VRRP与BFD联动功能
# 在RouterB上配置VRRP与BFD联动,当BFD会话状态Down时,RouterB的优先级增加40。
[RouterB] interface gigabitethernet 2/0/0 [RouterB-GigabitEthernet2/0/0] vrrp vrid 1 track bfd-session 2 increased 40 [RouterB-GigabitEthernet2/0/0] quit
- 验证配置结果
# 完成上述配置后,在RouterA和RouterB上分别执行display vrrp命令,可以看出RouterA为Master设备,RouterB为Backup设备,联动的BFD会话状态为UP。
[RouterA] display vrrp GigabitEthernet2/0/0 | Virtual Router 1 State : Master Virtual IP : 10.1.1.3 Master IP : 10.1.1.1 PriorityRun : 120 PriorityConfig : 120 MasterPriority : 120 Preempt : YES Delay Time : 20 s TimerRun : 1 s TimerConfig : 1 s Auth Type : NONE Virtual Mac : 0000-5e00-0101 Check TTL : YES Config type : normal-vrrp Backup-forward : disabled Create time : 2012-05-22 17:32:56 Last change time : 2012-05-22 17:33:00
[RouterB] display vrrp GigabitEthernet2/0/0 | Virtual Router 1 State : Backup Virtual IP : 10.1.1.3 Master IP : 10.1.1.1 PriorityRun : 100 PriorityConfig : 100 MasterPriority : 120 Preempt : YES Delay Time : 0 s TimerRun : 1 s TimerConfig : 1 s Auth Type : NONE Virtual Mac : 0000-5e00-0101 Check TTL : YES Config type : normal-vrrp Backup-forward : disabled Track BFD : 2 Priority increased : 40 BFD-Session State: UP Create time : 2012-05-22 17:33:00 Last change time : 2012-05-22 17:33:04
# 在RouterA的接口GE2/0/0上执行shutdown命令,模拟链路故障。此时在RouterA和RouterB上分别执行display vrrp命令,可以看出RouterA状态变为Initialize,RouterB状态变为Master,联动的BFD会话状态为DOWN。
[RouterA] interface gigabitethernet 2/0/0 [RouterA-GigabitEthernet2/0/0] shutdown [RouterA-GigabitEthernet2/0/0] quit
[RouterA] display vrrp GigabitEthernet2/0/0 | Virtual Router 1 State : Initialize Virtual IP : 10.1.1.3 Master IP : 0.0.0.0 PriorityRun : 120 PriorityConfig : 120 MasterPriority : 0 Preempt : YES Delay Time : 20 s TimerRun : 1 s TimerConfig : 1 s Auth Type : NONE Virtual Mac : 0000-5e00-0101 Check TTL : YES Config type : normal-vrrp Backup-forward : disabled Create time : 2012-05-22 17:32:56 Last change time : 2012-05-22 17:33:06
[RouterB] display vrrp GigabitEthernet2/0/0 | Virtual Router 1 State : Master Virtual IP : 10.1.1.3 Master IP : 10.1.1.2 PriorityRun : 140 PriorityConfig : 100 MasterPriority : 140 Preempt : YES Delay Time : 0 s TimerRun : 1 s TimerConfig : 1 s Auth Type : NONE Virtual Mac : 0000-5e00-0101 Check TTL : YES Config type : normal-vrrp Backup-forward : disabled Track BFD : 2 Priority increased : 40 BFD-Session State: DOWN Create time : 2012-05-22 17:33:00 Last change time : 2012-05-22 17:33:06
# 在RouterA的接口GE2/0/0上执行undo shutdown命令,模拟故障恢复。20秒后,分别在RouterA和RouterB上执行display vrrp命令,可以看出RouterA状态恢复为Master,RouterB状态恢复为Backup,联动的BFD会话状态恢复为UP。
[RouterA] interface gigabitethernet 2/0/0 [RouterA-GigabitEthernet2/0/0] undo shutdown [RouterA-GigabitEthernet2/0/0] quit
[RouterA] display vrrp GigabitEthernet2/0/0 | Virtual Router 1 State : Master Virtual IP : 10.1.1.3 Master IP : 10.1.1.1 PriorityRun : 120 PriorityConfig : 120 MasterPriority : 120 Preempt : YES Delay Time : 20 s TimerRun : 1 s TimerConfig : 1 s Auth Type : NONE Virtual Mac : 0000-5e00-0101 Check TTL : YES Config type : normal-vrrp Backup-forward : disabled Create time : 2012-05-22 17:32:56 Last change time : 2012-05-22 17:33:50
[RouterB] display vrrp GigabitEthernet2/0/0 | Virtual Router 1 State : Backup Virtual IP : 10.1.1.3 Master IP : 10.1.1.1 PriorityRun : 100 PriorityConfig : 100 MasterPriority : 120 Preempt : YES Delay Time : 0 s TimerRun : 1 s TimerConfig : 1 s Auth Type : NONE Virtual Mac : 0000-5e00-0101 Check TTL : YES Config type : normal-vrrp Backup-forward : disabled Track BFD : 2 Priority increased : 40 BFD-Session State: UP Create time : 2012-05-22 17:33:00 Last change time : 2012-05-22 17:33:50
配置文件
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RouterA的配置文件
# sysname RouterA # bfd # interface GigabitEthernet2/0/0 ip address 10.1.1.1 255.255.255.0 vrrp vrid 1 virtual-ip 10.1.1.3 vrrp vrid 1 priority 120 vrrp vrid 1 preempt-mode timer delay 20 # bfd atob bind peer-ip 10.1.1.2 interface GigabitEthernet2/0/0 discriminator local 1 discriminator remote 2 min-tx-interval 50 min-rx-interval 50 commit # return
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RouterB的配置文件
# sysname RouterB # bfd # interface GigabitEthernet2/0/0 ip address 10.1.1.2 255.255.255.0 vrrp vrid 1 virtual-ip 10.1.1.3 vrrp vrid 1 track bfd-session 2 increased 40 # bfd btoa bind peer-ip 10.1.1.1 interface GigabitEthernet2/0/0 discriminator local 2 discriminator remote 1 min-tx-interval 50 min-rx-interval 50 commit # return