BGP路由惩罚

Posted 2020-10-29

配置
R1#show run | s route
router eigrp 90
network 0.0.0.0
router bgp 1
bgp router-id 1.1.1.1
bgp log-neighbor-changes
network 1.1.1.1 mask 255.255.255.255
neighbor 2.2.2.2 remote-as 1
neighbor 2.2.2.2 update-source Loopback0
neighbor 2.2.2.2 next-hop-self
R2#show run | s route
router eigrp 90
network 2.0.0.0
network 12.0.0.0
router bgp 1
bgp router-id 2.2.2.2
bgp log-neighbor-changes
neighbor 1.1.1.1 remote-as 1
neighbor 1.1.1.1 update-source Loopback0
neighbor 1.1.1.1 next-hop-self
neighbor 3.3.3.3 remote-as 2
neighbor 3.3.3.3 ebgp-multihop 255
neighbor 3.3.3.3 update-source Loopback0
ip route 3.3.3.3 255.255.255.255 23.1.1.3
R3#show run | s bgp
router bgp 2
bgp router-id 3.3.3.3
bgp log-neighbor-changes
bgp dampening
neighbor 2.2.2.2 remote-as 1
neighbor 2.2.2.2 ebgp-multihop 255
neighbor 2.2.2.2 update-source Loopback0
R3#show run | s ip route
ip route 2.2.2.2 255.255.255.255 23.1.1.2
结果
(1)关闭 开启R1 lo0
R3#show ip bgp
BGP table version is 6, local router ID is 3.3.3.3
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

 Network          Next Hop            Metric LocPrf Weight Path

> 1.1.1.1/32 2.2.2.2 0 1 i
R3#show ip bgp
BGP table version is 5, local router ID is 3.3.3.3
Status codes: s suppressed, d damped, h history, valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

 Network          Next Hop            Metric LocPrf Weight Path

h 1.1.1.1/32 2.2.2.2 0 1 i
R3#show ip bgp
BGP table version is 6, local router ID is 3.3.3.3
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

 Network          Next Hop            Metric LocPrf Weight Path

> 1.1.1.1/32 2.2.2.2 0 1 i
(2)关闭 开启R1 lo0
R3#show ip bgp
BGP table version is 6, local router ID is 3.3.3.3
Status codes: s suppressed, d damped, h history, valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

 Network          Next Hop            Metric LocPrf Weight Path

> 1.1.1.1/32 2.2.2.2 0 1 i
R3#show ip bgp
BGP table version is 5, local router ID is 3.3.3.3
Status codes: s suppressed, d damped, h history, valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

 Network          Next Hop            Metric LocPrf Weight Path

h 1.1.1.1/32 2.2.2.2 0 1 i
R3#show ip bgp
BGP table version is 6, local router ID is 3.3.3.3
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

 Network          Next Hop            Metric LocPrf Weight Path

> 1.1.1.1/32 2.2.2.2
(3)关闭 开启R1 lo0
R3#show ip bgp
BGP table version is 6, local router ID is 3.3.3.3
Status codes: s suppressed, d damped, h history, valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

 Network          Next Hop            Metric LocPrf Weight Path

> 1.1.1.1/32 2.2.2.2 0 1 i
R3#show ip bgp
BGP table version is 5, local router ID is 3.3.3.3
Status codes: s suppressed, d damped, h history, valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

 Network          Next Hop            Metric LocPrf Weight Path

h 1.1.1.1/32 2.2.2.2 0 1 i
R3#show ip bgp
BGP table version is 6, local router ID is 3.3.3.3
Status codes: s suppressed, d damped, h history, valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found
R3#show ip bgp
BGP table version is 15, local router ID is 3.3.3.3
Status codes: s suppressed, d damped, h history, valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

 Network          Next Hop            Metric LocPrf Weight Path

d 1.1.1.1/32 2.2.2.2 0 1 i
清除惩罚
R3#clear ip bgp dampening
R3#show ip bgp
BGP table version is 16, local router ID is 3.3.3.3
Status codes: s suppressed, d damped, h history, valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

 Network          Next Hop            Metric LocPrf Weight Path

> 1.1.1.1/32 2.2.2.2 0 1 i
最大惩罚值=重用门限2^（最大惩罚时间min/半衰期min）
Bgp dampening 15 750 2000 60
15代表半衰期为15min，每15min减半。
750代表重用门限为750，当受到惩罚的路由降低到750以下，路由才可以重新加到表中。
2000代表惩罚门限为2000，当超过2000，该路由就开始受到抑制。
60代表最大惩罚时间为60min。
以上均为默认值。
代入公式可以得到最大惩罚志为12000=750*2^(60/15)