配置BGP路由振荡抑制示例
配置BGP路由振荡抑制可以保证网络的稳定性。
组网需求
如图10-42所示,所有路由器都配置BGP,DeviceA在AS100中,DeviceB在AS200中,DeviceC在AS300中,DeviceD在AS400中,DeviceC分别与DeviceA、DeviceB、DeviceD之间运行EBGP。针对不同的EBGP邻居路由,DeviceC应用不同的路由抑制策略。通过配置BGP振荡抑制,可以抑制不稳定的路由信息,增加网络的稳定性。
配置思路
采用如下的思路配置BGP路由振荡抑制:
在DeviceA和DeviceC、DeviceB和DeviceC、DeviceD和DeviceC之间分别配置EBGP连接。
在DeviceC上配置路由抑制策略,查看路由信息。
操作步骤
- 配置各接口的IP地址(略)
- 配置BGP连接
# 配置DeviceA。
[~DeviceA] bgp 100
[*DeviceA-bgp] router-id 1.1.1.1
[*DeviceA-bgp] peer 10.10.1.2 as-number 300
[*DeviceA-bgp] ipv4-family unicast
[*DeviceA-bgp-af-ipv4] network 8.0.0.0 255.0.0.0
[*DeviceA-bgp-af-ipv4] commit
[~DeviceA-bgp-af-ipv4] quit
[~DeviceA-bgp] quit
# 配置DeviceB。
[~DeviceB] bgp 200
[*DeviceB-bgp] router-id 2.2.2.2
[*DeviceB-bgp] peer 10.10.2.2 as-number 300
[*DeviceB-bgp] ipv4-family unicast
[*DeviceB-bgp-af-ipv4] network 9.1.1.0 255.255.255.0
[*DeviceB-bgp-af-ipv4] commit
[~DeviceB-bgp-af-ipv4] quit
[~DeviceB-bgp] quit
# 配置DeviceC。
[~DeviceC] bgp 300
[*DeviceC-bgp] router-id 3.3.3.3
[*DeviceC-bgp] peer 10.10.1.1 as-number 100
[*DeviceC-bgp] peer 10.10.2.1 as-number 200
[*DeviceC-bgp] peer 10.10.3.1 as-number 400
[*DeviceC-bgp] commit
[~DeviceC-bgp] quit
# 配置DeviceD。
[~DeviceD] bgp 400
[*DeviceD-bgp] router-id 4.4.4.4
[*DeviceD-bgp] peer 10.10.3.2 as-number 300
[*DeviceD-bgp] commit
[~DeviceD-bgp] quit
# 查看DeviceC的BGP对等体。
[*DeviceC] display bgp peer BGP local router ID : 3.3.3.3 Local AS number : 300 Total number of peers : 3 Peers in established state : 3 Peer V AS MsgRcvd MsgSent OutQ Up/Down State PrefRcv 10.10.1.1 4 100 3 3 0 00:00:01 Established 0 10.10.2.1 4 200 3 3 0 00:00:00 Established 0 10.10.3.1 4 400 3 3 0 00:00:01 Established 0
可以看出,DeviceC的BGP连接状态均为“Established”。
- 配置BGP路由振荡抑制策略
# 在DeviceC上配置名为prefix-a的地址前缀列表,允许前缀为8.0.0.0/8的路由通过。
[~DeviceC] ip ip-prefix prefix-a index 10 permit 8.0.0.0 8
[*DeviceC] commit
# 在DeviceC上配置名为prefix-b的地址前缀列表,允许前缀为9.1.1.0/24的路由通过。
[~DeviceC] ip ip-prefix prefix-b index 20 permit 9.1.1.0 24
[*DeviceC] commit
# 在DeviceC上配置名称为dampen-policy的Route-Policy,对不同前缀长度的路由采用不同的路由抑制策略。
[~DeviceC] route-policy dampen-policy permit node 10
[*DeviceC-route-policy] if-match ip-prefix prefix-a
[*DeviceC-route-policy] apply dampening 10 1000 2000 5000
[*DeviceC-route-policy] commit
[~DeviceC-route-policy] quit
[*DeviceC] route-policy dampen-policy permit node 20
[*DeviceC-route-policy] if-match ip-prefix prefix-b
[*DeviceC-route-policy] apply dampening 10 800 3000 10000
[*DeviceC-route-policy] commit
[~DeviceC-route-policy] quit
# 对振荡路由应用路由抑制策略。
[*DeviceC] bgp 300
[*DeviceC-bgp] ipv4-family unicast
[*DeviceC-bgp-af-ipv4] dampening route-policy dampen-policy
[*DeviceC-bgp-af-ipv4] commit
[~DeviceC-bgp] quit
# 在DeviceC上查看已配置的BGP路由振荡抑制参数。
[~DeviceC] display bgp routing-table dampening parameter Maximum Suppress Time(in second) : 3973 Ceiling Value : 16000 Reuse Value : 750 HalfLife Time(in second) : 900 Suppress-Limit : 2000 Route-policy : dampen-policy
配置文件
DeviceA的配置文件
#
sysname DeviceA
#
interface GigabitEthernet0/1/0
undo shutdown
ip address 10.10.1.1 255.255.255.0
#
interface GigabitEthernet0/2/0
undo shutdown
ip address 172.16.1.1 255.0.0.0
#
bgp 100
router-id 1.1.1.1
peer 10.10.1.2 as-number 300
#
ipv4-family unicast
undo synchronization network 8.0.0.0 255.0.0.0
peer 10.10.1.2 enable
#
return
DeviceB的配置文件
#
sysname DeviceB
#
interface GigabitEthernet0/1/0
undo shutdown
ip address 10.10.2.1 255.255.255.0
#
interface GigabitEthernet0/2/0
undo shutdown
ip address 192.168.1.1 255.255.255.0
#
bgp 200
router-id 2.2.2.2
peer 10.10.2.2 as-number 300
#
ipv4-family unicast
undo synchronization network 9.1.1.0 255.255.255.0
peer 10.10.2.2 enable
#
return
DeviceC的配置文件
#
sysname DeviceC
#
interface GigabitEthernet0/1/0
undo shutdown
ip address 10.10.1.2 255.255.255.0
#
interface GigabitEthernet0/2/0
undo shutdown
ip address 10.10.2.2 255.255.255.0
#
interface GigabitEthernet0/3/0
undo shutdown
ip address 10.10.3.2 255.255.255.0
#
bgp 300
router-id 3.3.3.3
peer 10.10.1.1 as-number 100
peer 10.10.2.1 as-number 200
peer 10.10.3.1 as-number 400
#
ipv4-family unicast
undo synchronization dampening route-policy dampen-policy
peer 10.10.1.1 enable
peer 10.10.2.1 enable
peer 10.10.3.1 enable
#
route-policy dampen-policy permit node 10
if-match ip-prefix prefix-a
apply dampening 10 1000 2000 5000
#
route-policy dampen-policy permit node 20
if-match ip-prefix prefix-b
apply dampening 10 800 3000 10000
#
ip ip-prefix prefix-a index 10 permit 8.0.0.0 8
#
ip ip-prefix prefix-b index 20 permit 9.1.1.0 24
#
return
DeviceD的配置文件
#
sysname DeviceB
#
interface GigabitEthernet0/1/0
undo shutdown
ip address 10.10.3.1 255.255.255.0
#
bgp 400
router-id 4.4.4.4
peer 10.10.3.2 as-number 300
#
ipv4-family unicast
undo synchronization peer 10.10.3.2 enable
#
return