BGP router-id OSPF router-id 路由同步实验
实验拓朴:
R1----------------- R2 --------------------R3
IBGP
全网
OSPF
实验基本配置：
R1
：
interface Loopback0
ip address 1.1.1 .1 255.255.255.255
!
interface Serial1/1
ip address 10.1.12 .1 255.255.255.0
!
router ospf 1
router-id 1.1.1 .1
log-adjacency-changes
network 10.1.12 .0 0.0.0.255 area 0
!
router bgp 1
bgp router-id 1.1.1 .1
bgp log-neighbor-changes
neighbor 10.1.12 .2 remote-as 1
no auto-summary
!
R2
：
interface Loopback0
ip address 2.2.2 .2 255.255.255.255
!
interface Serial1/0
ip address 10.1.12 .2 255.255.255.0
!
interface Serial1/1
ip address 10.1.23 .2 255.255.255.0
!
router ospf 1
router-id 2.2.2 .2
log-adjacency-changes
network 10.1.12 .0 0.0.0.255 area 0
network 10.1.23 .0 0.0.0.255 area 0
!
router bgp 1
bgp router-id 2.2.2 .2
bgp log-neighbor-changes
network 3.3.3 .3 mask 255.255.255.255
neighbor 10.1.12 .1 remote-as 1
no auto-summary
!
R3
：
interface Loopback0
ip address 3.3.3 .3 255.255.255.255
!
interface Serial1/0
ip address 10.1.23 .3 255.255.255.0
!
router ospf 1
router-id 3.3.3 .3
log-adjacency-changes
network 3.3.3 .3 0.0.0.0 area 0
network 10.1.23 .0 0.0.0.255 area 0
!
实验现象：
R1#sh ip bgp
BGP table version is 1, local router ID is 1.1.1 .1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
* i 3.3.3 .3/32 10.1.23 .3 65 100 0 i
R1#sh ip bg p 3.3.3 .3
BGP routing table entry for 3.3.3 .3/32, version 0
Paths: (1 available, no best path)
Not advertised to any peer
Local
10.1.23 .3 (metric 128) from 10.1.12.2 (2.2.2.2)
Origin IGP, metric 65, localpref 100, valid, internal, not synchronized
R1#sh ip route 3.3.3 .3
Routing entry for 3.3.3 .3/32
Known via "ospf 1", distance 110, metric 129, type intra area
Last update from 10.1.12 .2 on Serial1/1, 00:01:01 ago
Routing Descriptor Blocks:
* 10.1.12 .2, from 3.3.3.3, 00:01:01 ago, via Serial1/1
Route metric is 129, traffic share count is 1
R3
的
lo0 3.3.3 .3
在
R2
上通过
BGP
中
network
通告给
R1
，但
R1
收到的
OSPF
路由的
router-id (show ip route 3.3.3.3)
为
3.3.3.3
，
R1 BGP
路由的
router-id (show ip bgp 3.3.3.3)
为
2.2.2.2
，两者不一致，未同步，
show ip bgp
中有
3.3.3.3
，但非最优路径
无
> .
更改
R2 BGP
配置中的
router-id
为
3.3.3 .3
，结果：
R1#sh ip bgp
BGP table version is 2, local router ID is 1.1.1 .1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*>i 3.3.3 .3/32 10.1.23 .3 65 100 0 i
R1#sh ip bg p 3.3.3 .3
BGP routing table entry for 3.3.3 .3/32, version 2
Paths: (1 available, best #1, table Default-IP-Routing-Table)
Flag: 0x208
Not advertised to any peer
Local
10.1.23 .3 (metric 128) from 10.1.12.2 (3.3.3.3)
Origin IGP, metric 65, localpref 100, valid, internal, synchronized, best
扩展
R2#sh ip route 3.3.3 .3
Routing entry for 3.3.3 .3/32
Known via "ospf 1", distance 110, metric 65, type intra area
Advertised by bgp 1
Last update from 10.1.23 .3 on Serial1/1, 00:12:34 ago
Routing Descriptor Blocks:
* 10.1.23 .3, from 3.3.3.3, 00:12:34 ago, via Serial1/1
Route metric is 65, traffic share count is 1
R2#sh ip bg p 3.3.3 .3
BGP routing table entry for 3.3.3 .3/32, version 2
Paths: (1 available, best #1, table Default-IP-Routing-Table)
Advertised to non peer-group peers:
10.1.12 .1
Local
10.1.23 .3 from 0.0.0.0 (2.2.2.2)
Origin IGP, metric 65, localpref 100, weight 32768, valid, sourced, local, best
R2
在开启同步的情况下
show ip bg p 3.3.3 .3
始终有
>
，本地通告
net 3.3.3.3
，同样
OSPF
和
BGP
的
router-id
不一致
,
但路由可以最优
.
理解同步检查用在什么时候
：
IBGP
传过来的路由，进行检查
.