BGP local router ID : 1.1.1.1 Local AS number : 100 Total number of peers : 1 Peers in established state : 0
Peer V AS MsgRcvd MsgSent OutQ Up/Down State Pre fRcv
12.1.1.2 4 200 1 3 0 00:00:32 OpenConfirm 0 [R1] Mar 4 2024 11:58:48-08:00 R1 %%01BGP/3/STATE_CHG_UPDOWN(l)[5]:The status of the peer 12.1.1.2 changed from OPENCONFIRM to ESTABLISHED. (InstanceName=Public, St ateChangeReason=Up) display bgp peer
[R1]Ping -a 1.1.1.1 4.4.4.4 PING 4.4.4.4: 56 data bytes, press CTRL_C to break Reply from 4.4.4.4: bytes=56 Sequence=1 ttl=255 time=60 ms Reply from 4.4.4.4: bytes=56 Sequence=2 ttl=255 time=30 ms Reply from 4.4.4.4: bytes=56 Sequence=3 ttl=255 time=20 ms Reply from 4.4.4.4: bytes=56 Sequence=4 ttl=255 time=20 ms Reply from 4.4.4.4: bytes=56 Sequence=5 ttl=255 time=30 ms
BGP Local router ID is 4.4.4.4 Status codes: * - valid, > - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete
Total Number of Routes: 1 Network NextHop MED LocPrf PrefVal Path/Ogn
BGP Local router ID is 4.4.4.4 Status codes: * - valid, > - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete
Total Number of Routes: 1 Network NextHop MED LocPrf PrefVal Path/Ogn
*> 10.1.1.0/24 0.0.0.0 0 0 i
[R4-bgp]import-route ? direct Connected routes isis Intermediate System to Intermediate System (IS-IS) routes ospf Open Shortest Path First (OSPF) routes rip Routing Information Protocol (RIP) routes static Static routes unr User network routes
BGP Local router ID is 3.3.3.3 Status codes: * - valid, > - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete
Total Number of Routes: 5 Network NextHop MED LocPrf PrefVal Path/Ogn
BGP Local router ID is 3.3.3.3 Status codes: * - valid, > - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete
Total Number of Routes: 10 Network NextHop MED LocPrf PrefVal Path/Ogn
[R1]dis ip routing-table Route Flags: R - relay, D - download to fib ------------------------------------------------------------------------------ Routing Tables: Public Destinations : 20 Routes : 20
Destination/Mask Proto Pre Cost Flags NextHop Interface
1.1.1.1/32 Direct 0 0 D 127.0.0.1 LoopBack0 2.2.2.2/32 OSPF 10 1 D 12.1.1.2 GigabitEthernet0/0/0 3.3.3.3/32 OSPF 10 2 D 12.1.1.2 GigabitEthernet0/0/0 4.4.4.4/32 Static 60 0 RD 14.1.1.4 GigabitEthernet0/0/1 10.1.1.0/24 EBGP 255 0 RD 4.4.4.4 GigabitEthernet0/0/1 12.1.1.0/24 Direct 0 0 D 12.1.1.1 GigabitEthernet0/0/0 12.1.1.1/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0 12.1.1.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0 14.1.1.0/24 Direct 0 0 D 14.1.1.1 GigabitEthernet0/0/1 14.1.1.1/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1 14.1.1.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1 23.1.1.0/24 OSPF 10 2 D 12.1.1.2 GigabitEthernet0/0/0 30.1.0.0/24 IBGP 255 0 RD 3.3.3.3 GigabitEthernet0/0/0 30.1.1.0/24 IBGP 255 0 RD 3.3.3.3 GigabitEtherne0/0/0 30.1.2.0/24 IBGP 255 0 RD 3.3.3.3 GigabitEthernet0/0/0 30.1.3.0/24 IBGP 255 0 RD 3.3.3.3 GigabitEthernet0/0/0 127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0 127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0 127.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0 255.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
BGP Local router ID is 2.2.2.2 Status codes: * - valid, > - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete
Total Number of Routes: 11 Network NextHop MED LocPrf PrefVal Path/Ogn
Destination/Mask Proto Pre Cost Flags NextHop Interface
1.1.1.1/32 OSPF 10 1 D 12.1.1.1 GigabitEthernet0/0/0 2.2.2.2/32 Direct 0 0 D 127.0.0.1 LoopBack0 3.3.3.3/32 OSPF 10 1 D 23.1.1.3 GigabitEthernet0/0/1 12.1.1.0/24 Direct 0 0 D 12.1.1.2 GigabitEthernet0/0/0 12.1.1.2/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0 12.1.1.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0 23.1.1.0/24 Direct 0 0 D 23.1.1.2 GigabitEthernet0/0/1 23.1.1.2/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1 23.1.1.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1 30.1.0.0/24 IBGP 255 0 RD 3.3.3.3 GigabitEthernet0/0/1 30.1.1.0/24 IBGP 255 0 RD 3.3.3.3 GigabitEtherne0/0/1 30.1.2.0/24 IBGP 255 0 RD 3.3.3.3 GigabitEthernet0/0/1 30.1.3.0/24 IBGP 255 0 RD 3.3.3.3 GigabitEthernet0/0/1 127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0 127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0 127.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0 255.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
<R2>
[R1]ospf 1 [R1-ospf-1]import-route static
[R2]dis ip routing-table Route Flags: R - relay, D - download to fib ------------------------------------------------------------------------------ Routing Tables: Public Destinations : 20 Routes : 20
Destination/Mask Proto Pre Cost Flags NextHop Interface
1.1.1.1/32 OSPF 10 1 D 12.1.1.1 GigabitEthernet0/0/0 2.2.2.2/32 Direct 0 0 D 127.0.0.1 LoopBack0 3.3.3.3/32 OSPF 10 1 D 23.1.1.3 GigabitEthernet0/0/1 4.4.4.4/32 O_ASE 150 1 D 12.1.1.1 GigabitEthernet0/0/0 10.1.1.0/24 IBGP 255 0 RD 4.4.4.4 GigabitEthernet0/0/0 10.4.4.0/24 IBGP 255 0 RD 4.4.4.4 GigabitEthernet0/0/0 12.1.1.0/24 Direct 0 0 D 12.1.1.2 GigabitEthernet0/0/0 12.1.1.2/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0 12.1.1.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0 23.1.1.0/24 Direct 0 0 D 23.1.1.2 GigabitEthernet0/0/1 23.1.1.2/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1 23.1.1.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1 30.1.0.0/24 IBGP 255 0 RD 3.3.3.3 GigabitEthernet0/0/1 30.1.1.0/24 IBGP 255 0 RD 3.3.3.3 GigabitEthernet0/0/1 30.1.2.0/24 IBGP 255 0 RD 3.3.3.3 GigabitEthernet0/0/1 30.1.3.0/24 IBGP 255 0 RD 3.3.3.3 GigabitEthernet0/0/1 127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0 127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0 127.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0 255.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
[R2]
[R2]dis bgp routing-table
BGP Local router ID is 2.2.2.2 Status codes: * - valid, > - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete
Total Number of Routes: 12 Network NextHop MED LocPrf PrefVal Path/Ogn
BGP Local router ID is 2.2.2.2 Status codes: * - valid, > - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete
Total Number of Routes: 11 Network NextHop MED LocPrf PrefVal Path/Ogn
[R2]dis ip routing-table Route Flags: R - relay, D - download to fib ------------------------------------------------------------------------------ Routing Tables: Public Destinations : 19 Routes : 19
Destination/Mask Proto Pre Cost Flags NextHop Interface
1.1.1.1/32 OSPF 10 1 D 12.1.1.1 GigabitEthernet0/0/0 2.2.2.2/32 Direct 0 0 D 127.0.0.1 LoopBack0 3.3.3.3/32 OSPF 10 1 D 23.1.1.3 GigabitEthernet0/0/1 10.1.1.0/24 IBGP 255 0 RD 1.1.1.1 GigabitEthernet0/0/0 10.4.4.0/24 IBGP 255 0 RD 1.1.1.1 GigabitEthernet0/0/0 12.1.1.0/24 Direct 0 0 D 12.1.1.2 GigabitEthernet0/0/0 12.1.1.2/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0 12.1.1.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0 23.1.1.0/24 Direct 0 0 D 23.1.1.2 GigabitEthernet0/0/1 23.1.1.2/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1 23.1.1.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1 30.1.0.0/24 IBGP 255 0 RD 3.3.3.3 GigabitEthernet0/0/1 30.1.1.0/24 IBGP 255 0 RD 3.3.3.3 GigabitEthernet0/0/1 30.1.2.0/24 IBGP 255 0 RD 3.3.3.3 GigabitEthernet0/0/1 30.1.3.0/24 IBGP 255 0 RD 3.3.3.3 GigabitEthernet0/0/1 127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0 127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0 127.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0 255.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
[R2]
BGP 路由通告原则
BGP 只通告最优的路由.
* 表示该路由是有效的
> 表示该路由是最优的
从 EBGP 对等体获取的路由会通告给所有的 BGP 对等体 (EBGP 和 IBGP).
从 IBGP 对等体获取的路由不会通告给 IBGP 对等体 (IBGP 水平分割原则,用于防止 AS 内路由环路问题) 为了防止 AS 内部分设备无法收到 BGP 路由,可以通过配置 IBGP 全互联来解决,但 IBGP 全互联可能会导致网络结构复杂,例如关系数量过多等问题,导致扩展性差,此时可以通过 BGP 路由反射器和 BGP 联盟来简化 AS 内的拓扑结构.
<R1>ping -a 1.1.1.1 5.5.5.5 PING 5.5.5.5: 56 data bytes, press CTRL_C to break Request time out Request time out Request time out Request time out Request time out
--- 5.5.5.5 ping statistics --- 5 packet(s) transmitted 0 packet(s) received 100.00% packet loss
<R3>dis ip routing-table Route Flags: R - relay, D - download to fib ------------------------------------------------------------------------------ Routing Tables: Public Destinations : 13 Routes : 13
Destination/Mask Proto Pre Cost Flags NextHop Interface
2.2.2.2/32 OSPF 10 1 D 23.1.1.2 GigabitEthernet0/0/0 3.3.3.3/32 Direct 0 0 D 127.0.0.1 LoopBack0 4.4.4.4/32 OSPF 10 1 D 34.1.1.4 GigabitEthernet0/0/1 23.1.1.0/24 Direct 0 0 D 23.1.1.3 GigabitEthernet0/0/0 23.1.1.3/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0 23.1.1.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0 34.1.1.0/24 Direct 0 0 D 34.1.1.3 GigabitEthernet0/0/1 34.1.1.3/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1 34.1.1.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1 127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0 127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0 127.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0 255.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
BGP注入OSPF [R2-ospf-1]import-route bgp
[R2-ospf-1]dis ospf lsdb
OSPF Process 1 with Router ID 2.2.2.2 Link State Database
AS External Database Type LinkState ID AdvRouter Age Len Sequence Metric External 5.5.5.5 4.4.4.4 23 36 80000001 1 External 1.1.1.1 2.2.2.2 63 36 80000001 1 <R3>dis ip routing-table Route Flags: R - relay, D - download to fib ------------------------------------------------------------------------------ Routing Tables: Public Destinations : 15 Routes : 15
Destination/Mask Proto Pre Cost Flags NextHop Interface
1.1.1.1/32 O_ASE 150 1 D 23.1.1.2 GigabitEthernet0/0/0 2.2.2.2/32 OSPF 10 1 D 23.1.1.2 GigabitEthernet0/0/0 3.3.3.3/32 Direct 0 0 D 127.0.0.1 LoopBack0 4.4.4.4/32 OSPF 10 1 D 34.1.1.4 GigabitEthernet0/0/1 5.5.5.5/32 O_ASE 150 1 D 34.1.1.4 GigabitEthernet0/0/1 23.1.1.0/24 Direct 0 0 D 23.1.1.3 GigabitEthernet0/0/0 23.1.1.3/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0 23.1.1.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0 34.1.1.0/24 Direct 0 0 D 34.1.1.3 GigabitEthernet0/0/1 34.1.1.3/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1 34.1.1.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1 127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0 127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0 127.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0 255.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
[R1]ping -a 1.1.1.1 5.5.5.5 PING 5.5.5.5: 56 data bytes, press CTRL_C to break Reply from 5.5.5.5: bytes=56 Sequence=1 ttl=252 time=80 ms Reply from 5.5.5.5: bytes=56 Sequence=2 ttl=252 time=50 ms Reply from 5.5.5.5: bytes=56 Sequence=3 ttl=252 time=60 ms Reply from 5.5.5.5: bytes=56 Sequence=4 ttl=252 time=50 ms Reply from 5.5.5.5: bytes=56 Sequence=5 ttl=252 time=40 ms
--- 5.5.5.5 ping statistics --- 5 packet(s) transmitted 5 packet(s) received 0.00% packet loss round-trip min/avg/max = 40/56/80 ms
当去往同一个目的地存在多条起源属性不同的路由时,如果其他条件都相同,则按照起源代码 i 优于 e 优于?的顺序加表.
AS_PATH
AS_PATH:AS 路径属性,是一个公认必遵属性,用于描述一个 BGP 路由所经过的 AS 路径信息,本地始发的路由 AS_PATH 属性为空,当路由传递给 EBGP PEER 时,会将自身的 AS 号添加到 AS_PATH 中
AS_PATH 可以用于 BGP 的 AS 间路由防环,当从 EBGP 接收路由时,如果发现路由中的 AS_PATH 已经包含自身的 AS 号,则拒绝接收该路由.
如果从不同的路径收到相同目的地的路由,且其他属性完全相同,此时会优选 AS-PATH 较短的路由.
bestroute as-path-ignore // 通过此命令可以忽略AS-PATH长短的比较
<R2>dis bgp routing-table
BGP Local router ID is 2.2.2.2 Status codes: * - valid, > - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete
Total Number of Routes: 6 Network NextHop MED LocPrf PrefVal Path/Ogn
BGP Local router ID is 5.5.5.5 Status codes: * - valid, > - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete
Total Number of Routes: 6 Network NextHop MED LocPrf PrefVal Path/Ogn
BGP Local router ID is 5.5.5.5 Status codes: * - valid, > - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete
Total Number of Routes: 6 Network NextHop MED LocPrf PrefVal Path/Ogn
BGP Local router ID is 1.1.1.1 Status codes: * - valid, > - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete
Total Number of Routes: 2 Network NextHop MED LocPrf PrefVal Path/Ogn
BGP Local router ID is 2.2.2.2 Status codes: * - valid, > - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete
Total Number of Routes: 2 Network NextHop MED LocPrf PrefVal Path/Ogn
BGP Local router ID is 3.3.3.3 Status codes: * - valid, > - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete
Total Number of Routes: 3 Network NextHop MED LocPrf PrefVal Path/Ogn
i 1.1.1.1/32 1.1.1.1 0 100 0 i i 2.2.2.2/32 12.1.1.2 0 100 0 200i *>i 11.1.1.1/32 1.1.1.1 0 100 0 i
[R2-bgp]display bgp routing-table
BGP Local router ID is 2.2.2.2 Status codes: * - valid, > - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete
Total Number of Routes: 3 Network NextHop MED LocPrf PrefVal Path/Ogn
簇 id: 簇 id 是反射器簇的标识,具备相同簇 id 的反射器在同一个簇内,如果没有配置簇 id, 则缺省用设备的 RID 作为族 id.
[R1-bgp]reflector cluster-id x.x.x.x // 手动设置更改簇id
Cluster_id list
Cluster_id list: 簇 id 列表,用于在 BGP 路由反射器簇直接进行防环,是一个可选非过渡属性,当路由器第一次反射路由时,反射器会创建该属性,并将自身的簇 id 添加到列表中。当路由反射器接收到携带簇 id 列表的路由时,会检查列表是否包含自身的簇 id 信息,如果不包含,则正常接收处理,如果包含自身的族 id, 则拒绝接收该路由.
[R5-bgp]aggregate 10.1.0.0 255.255.248.0 ? as-set Generate the route with AS-SET path-attribute attribute-policy Set aggregation attributes detail-suppressed Filter more detail route from updates origin-policy Filter the originate routes of the aggregate suppress-policy Filter more detail route from updates through a Routing policy <cr> [R5-bgp]aggregate 10.1.0.0 255.255.248.0 detail-suppressed
[R5]route-policy set-com permit node 10 [R5-route-policy]apply community 100:100 [R5-bgp]aggregate 10.1.0.0 255.255.248.0 detail-suppressed as-set attribute-policy set-com Warning: set-com used as BGP attribute-policy, apply as-path is not supported. [R5-bgp]dis bgp r community Total Number of Routes: 1 Network NextHop MED LocPrf PrefVal Community
BGP Local router ID is 5.5.5.5 Status codes: * - valid, > - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete
Total Number of Routes: 9 Network NextHop MED LocPrf PrefVal Community