实验目标:掌握BGP的路由传递原则
实验TOP:
基本配置
R1
!
hostname R1
!
no ip domain lookup
!
interface Loopback0
ipaddress 1.1.1.1 255.255.255.0
!
interface Loopback10
ipaddress 10.10.10.10 255.255.255.0
ipospf network point-to-point
!
interface Serial1/0
ipaddress 12.1.1.1 255.255.255.0
!
interface Serial1/1
ipaddress 13.1.1.1 255.255.255.0
!
router ospf 10
router-id 1.1.1.1
network 10.10.10.0 0.0.0.255 area 0
network 12.1.1.0 0.0.0.255 area 0
network 13.1.1.0 0.0.0.255 area 0
!
router bgp 65001
nosynchronization
bgprouter-id 1.1.1.1
network 1.1.1.0 mask 255.255.255.0
neighbor 12.1.1.2 remote-as 65001
neighbor 13.1.1.3 remote-as 65001
noauto-summary
!
R2
!
hostname R2
!
no ip domain lookup
!
interface Loopback0
ipaddress 2.2.2.2 255.255.255.0
!
interface Loopback10
ipaddress 20.20.20.20 255.255.255.0
ipospf network point-to-point
!
interface Serial1/0
ipaddress 24.2.2.2 255.255.255.0
!
interface Serial1/1
ipaddress 12.1.1.2 255.255.255.0
!
router ospf 10
router-id 2.2.2.2
network 12.1.1.0 0.0.0.255 area 0
network 20.20.20.0 0.0.0.255 area 0
network 24.2.2.0 0.0.0.255 area 0
!
router bgp 65001
nosynchronization
bgprouter-id 2.2.2.2
network 2.2.2.0 mask 255.255.255.0
neighbor12.1.1.1 remote-as 65001
neighbor 24.2.2.4 remote-as 65001
noauto-summary
!
R3
!
hostname R3
!
no ip domain lookup
!
interface Loopback0
ipaddress 3.3.3.3 255.255.255.0
!
interface Loopback10
ipaddress 30.30.30.30 255.255.255.0
ipospf network point-to-point
!
interface Serial1/1
ipaddress 13.1.1.3 255.255.255.0
!
interface Serial1/0
ipaddress 34.3.3.3 255.255.255.0
!
router ospf 10
router-id 3.3.3.3
network 13.1.1.0 0.0.0.255 area 0
network 30.30.30.0 0.0.0.255 area 0
network34.3.3.0 0.0.0.255 area 0
!
router bgp 65001
nosynchronization
bgprouter-id 3.3.3.3
network 3.3.3.0 mask 255.255.255.0
neighbor 13.1.1.1 remote-as 65001
neighbor 34.3.3.4 remote-as 65001
no auto-summary
!
R4
!
hostname R4
!
no ip domain lookup
!
interface Loopback0
ipaddress 4.4.4.4 255.255.255.0
!
interface Loopback10
ipaddress 40.40.40.40 255.255.255.0
ipospf network point-to-point
!
interface Serial1/0
ipaddress 24.2.2.4 255.255.255.0
!
interface Serial1/1
ipaddress 34.3.3.4 255.255.255.0
!
Interface Serial1/2
Ip address 45.4.4.4 255.255.255.0
!
Interface Serial1/3
Ip address 46.4.4.4 255.255.255.0
!
router ospf 10
router-id 4.4.4.4
network 40.40.40.0 0.0.0.255 area 0
network 24.2.2.0 0.0.0.255 area 0
network 34.3.3.0 0.0.0.255 area 0
!
router bgp 65001
nosynchronization
bgprouter-id 4.4.4.4
network 4.4.4.0 mask 255.255.255.0
neighbor 24.2.2.2 remote-as 65001
neighbor 34.3.3.3 remote-as 65001
neighbor 45.4.4.5 remote-as 65002
neighbor 46.4.4.6 remote-as 65003
noauto-summary
!
R5
!
Hostname R5
!
no ip domain lookup
!
interface Loopback0
ipaddress 5.5.5.5 255.255.255.0
!
interface Serial1/0
ipaddress 45.4.4.5 255.255.255.0
!
router bgp 65002
nosynchronization
bgprouter-id 5.5.5.5
network 5.5.5.0 mask 255.255.255.0
neighbor 45.4.4.4 remote-as 65001
noauto-summary
!
R6
!
hostnameR6
!
interfaceLoopback0
ip address 6.6.6.6 255.255.255.0
!
interfaceSerial1/0
ip address 46.4.4.6 255.255.255.0
!
routerbgp 65003
no synchronization
bgp router-id 6.6.6.6
network 6.6.6.0 mask 255.255.255.0
neighbor 46.4.4.4 remote-as 65001
no auto-summary
!
批注:路由器接口默认是关闭的,所以应将对应的接口开启
基本配置完成之后,我们开始检查BGP对等体关系是否正常建立
R1#show ip bgp summary
BGP router identifier 1.1.1.1, local AS number 65001
BGP table version is 4, main routing table version 4
3 network entries using 303 bytes of memory
3 path entries using 144 bytes of memory
2 BGP path attribute entries using 120 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 567 total bytes of memory
BGP activity 3/0 prefixes, 3/0 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
12.1.1.2 4 65001 10 10 4 0 0 00:05:28 1
13.1.1.3 4 65001 9 9 4 0 0 00:04:42 1
R1#
//R1此时已经正常与R2和R3建立iBGP对等体关系
R2#show ip bgp summary
BGP router identifier 2.2.2.2, local AS number 65001
BGP table version is 4, main routing table version 4
5 network entries using 505 bytes of memory
5 path entries using 240 bytes of memory
4 BGP path attribute entries using 240 bytes of memory
2 BGP AS-PATH entries using 48 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 1033 total bytes of memory
BGP activity 5/0 prefixes, 5/0 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
12.1.1.1 4 65001 11 11 4 0 0 00:06:13 1
24.2.2.4 4 65001 11 9 4 0 0 00:04:51 3
R2#
//R2此时已经正常与R1和R4建立iBGP对等体关系
R3#show ip bgp summary
BGP router identifier 3.3.3.3, local AS number 65001
BGP table version is 4, main routing table version 4
5 network entries using 505 bytes of memory
5 path entries using 240 bytes of memory
4 BGP path attribute entries using 240 bytes of memory
2 BGP AS-PATH entries using 48 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 1033 total bytes of memory
BGP activity 5/0 prefixes, 5/0 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
13.1.1.1 4 65001 10 10 4 0 0 00:05:53 1
34.3.3.4 4 65001 12 10 4 0 0 00:05:16 3
R3#
//R3此时已经正常与R1和R4建立iBGP对等体关系
R4#show ip bgp summary
BGP router identifier 4.4.4.4, local AS number 65001
BGP table version is 6, main routing table version 6
5 network entries using 505 bytes of memory
5 path entries using 240 bytes of memory
4 BGP path attribute entries using 240 bytes of memory
2 BGP AS-PATH entries using 48 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 1033 total bytes of memory
BGP activity 5/0 prefixes, 5/0 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
24.2.2.2 4 65001 11 13 6 0 0 00:06:13 1
34.3.3.3 4 65001 11 13 6 0 0 00:06:13 1
45.4.4.5 4 65002 9 11 6 0 0 00:04:34 1
46.4.4.6 4 65003 9 11 6 0 0 00:04:10 1
R4#
//R4此时已经正常与R2和R3建立iBGP对等体关系,并且与R5和R6建立eBGP对等体关系
R5#show ip bgp summary
BGP router identifier 5.5.5.5, local AS number 65002
BGP table version is 6, main routing table version 6
5 network entries using 505 bytes of memory
5 path entries using 240 bytes of memory
4 BGP path attribute entries using 240 bytes of memory
2 BGP AS-PATH entries using 48 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 1033 total bytes of memory
BGP activity 5/0 prefixes, 5/0 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
45.4.4.4 4 65001 11 9 6 0 0 00:04:53 4
R5#
//R5此时已经正常与R4建立eBGP对等体关系
R6#show ip bgp summary
BGP router identifier 6.6.6.6, local AS number 65003
BGP table version is 6, main routing table version 6
5 network entries using 505 bytes of memory
5 path entries using 240 bytes of memory
4 BGP path attribute entries using 240 bytes of memory
2 BGP AS-PATH entries using 48 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 1033 total bytes of memory
BGP activity 5/0 prefixes, 5/0 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
46.4.4.4 4 65001 11 9 6 0 0 00:04:56 4
R6#
//R6此时已经正常与R4建立eBGP对等体关系
1.IBGP路由器从直连IBGP对等体学来的路由条目不会再传送给另外一个直连IBGP对等体。
如下图所示,如果R3不会将自己从iBGP对等体R1学习到的1.1.1.0/24网段传递给另一个iBGP对等体R4证明此结论正确。
首先我们查看R3的bgp表:
R3#show ip bgp
BGP table version is 4, local router ID is3.3.3.3
Status codes: s suppressed, d damped, hhistory, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? -incomplete
Network Next Hop Metric LocPrf Weight Path
*>i1.1.1.0/24 13.1.1.1 0 100 0 i
*> 3.3.3.0/24 0.0.0.0 0 32768 i
*>i4.4.4.0/24 34.3.3.4 0 100 0 i
* i5.5.5.0/24 45.4.4.5 0 100 0 65002 i
* i6.6.6.0/24 46.4.4.6 0 100 0 65003 i
//我们发现R3学习到了R1的lo0
再来查看R4的BGP表
R4#show ip bgp
BGP table version is 6, local router ID is 4.4.4.4
Status codes: s suppressed, d damped, h history, * valid, > best, i -internal,
r RIB-failure, SStale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*>i2.2.2.0/24 24.2.2.2 0 100 0 i
*>i3.3.3.0/24 34.3.3.3 0 100 0 i
*> 4.4.4.0/24 0.0.0.0 0 32768 i
*> 5.5.5.0/24 45.4.4.5 0 0 65002 i
*> 6.6.6.0/24 46.4.4.6 0 0 65003 i
R4#
//我们发现R4并没有学习到了R1的lo0
2.IBGP路由器会将自己从其他IBGP对等体学来的条目传给自身直连的EBGP对等体。
如果R5学习到R3的3.3.3.0/24路由条目,确定此结论正确。
首先我们查看R4的BGP表
R4#show ip bgp
BGP table version is 6, local router ID is4.4.4.4
Status codes: s suppressed, d damped, hhistory, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? -incomplete
Network Next Hop Metric LocPrf Weight Path
*>i2.2.2.0/24 24.2.2.2 0 100 0 i
*>i3.3.3.0/24 34.3.3.3 0 100 0 i
*> 4.4.4.0/24 0.0.0.0 0 32768 i
*> 5.5.5.0/24 45.4.4.5 0 0 65002 i
*> 6.6.6.0/24 46.4.4.6 0 0 65003 i
R4#
//R4学习到R3的路由
再来查看R5的BGP表
R5#show ip bgp
BGP table version is 6, local router ID is5.5.5.5
Status codes: s suppressed, d damped, hhistory, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? -incomplete
Network Next Hop Metric LocPrf Weight Path
*> 2.2.2.0/24 45.4.4.4 0 65001 i
*>3.3.3.0/24 45.4.4.4 0 65001 i
*> 4.4.4.0/24 45.4.4.4 0 0 65001 i
*> 5.5.5.0/24 0.0.0.0 0 32768 i
*> 6.6.6.0/24 45.4.4.4 0 65001 65003 i
R5#
//我们发现R5确实学习到了R3 的路由,证明上结论没有问题
3.从EBGP对等体学来的路由条目会传递给自身直连的IBGP对等体。
如果R4从eBGP对等体R5学习到5.5.5.0/24网段可以传递给iBGP对等体R3,则可证明结论正确
那么首先我们查看R4的BGP表
R4#show ip bgp
BGP table version is 6, local router ID is4.4.4.4
Status codes: s suppressed, d damped, hhistory, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? -incomplete
Network Next Hop Metric LocPrf Weight Path
*>i2.2.2.0/24 24.2.2.2 0 100 0 i
*>i3.3.3.0/24 34.3.3.3 0 100 0 i
*> 4.4.4.0/24 0.0.0.0 0 32768 i
*>5.5.5.0/24 45.4.4.5 0 0 65002 i
*> 6.6.6.0/24 46.4.4.6 0 0 65003 i
R4#
//我们发现R4学习到了5.5.5.0的路由
再来查看R3的bgp表
R3#show ip bgp
BGP table version is 4, local router ID is3.3.3.3
Status codes: s suppressed, d damped, hhistory, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*>i1.1.1.0/24 13.1.1.1 0 100 0 i
*> 3.3.3.0/24 0.0.0.0 0 32768 i
*>i4.4.4.0/24 34.3.3.4 0 100 0 i
*i5.5.5.0/24 45.4.4.5 0 100 0 65002 i
* i6.6.6.0/24 46.4.4.6 0 100 0 65003 i
R3#
//我们发现R3也学习到了5.5.5.0/24,说明R4会传递R5的5.5.5.0/24网段
4.从EBGP对等体学来的路由条目会传递给其他EBGP对等体。
我们可以在R5和R6上测试,观察R4从eBGP对等体R6学习到的6.6.6.0/24是否会传递给eBGP对等体R5
首先,我们查看R4的bgp表
R4#show ip bgp
BGP table version is 6, local router ID is 4.4.4.4
Status codes: s suppressed, d damped, h history, * valid, >best, i - internal,
rRIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*>i2.2.2.0/24 24.2.2.2 0 100 0 i
*>i3.3.3.0/24 34.3.3.3 0 100 0 i
*> 4.4.4.0/24 0.0.0.0 0 32768 i
*> 5.5.5.0/24 45.4.4.5 0 0 65002 i
*> 6.6.6.0/24 46.4.4.6 0 0 65003 i
R4#
//我们发现R4学习到了R6的6.6.6.0/24
再来查看R5的bgp表
R5#showip bgp
BGPtable version is 6, local router ID is 5.5.5.5
Statuscodes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origincodes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*>2.2.2.0/24 45.4.4.4 0 65001 i
*>3.3.3.0/24 45.4.4.4 0 65001 i
*>4.4.4.0/24 45.4.4.4 0 0 65001 i
*>5.5.5.0/24 0.0.0.0 0 32768 i
*> 6.6.6.0/24 45.4.4.4 0 65001 65003 i
//此时R5也同样学习到R6的6.6.6.0/24网络,证明结论没有问题
5.从IBGP对等体学来的路由条目再传送给EBGP对等体,下一跳会改成自己的出口。
我们测试R2的2.2.2.0/24网段在传递给iBGP对等体R4后,由R4在传递给直连的eBGP对等体,下一跳是否修改?
首先,我们查看R4的BGP表
R4#showip bgp
BGPtable version is 6, local router ID is 4.4.4.4
Statuscodes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origincodes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*>i2.2.2.0/24 24.2.2.2 0 100 0 i
*>i3.3.3.0/24 34.3.3.3 0 100 0 i
*>4.4.4.0/24 0.0.0.0 0 32768 i
*>5.5.5.0/24 45.4.4.5 0 0 65002 i
*>6.6.6.0/24 46.4.4.6 0 0 65003 i
//我们发现此时R4从iBGP对等体R2学习到的2.2.2.0/24网段的下一跳为R2的出口IP地址24.2.2.2
再来查看R5的BGP表
R5#showip bgp
BGPtable version is 6, local router ID is 5.5.5.5
Statuscodes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origincodes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 2.2.2.0/24 45.4.4.4 0 65001 i
*>3.3.3.0/24 45.4.4.4 0 65001 i
*>4.4.4.0/24 45.4.4.4 0 0 65001 i
*>5.5.5.0/24 0.0.0.0 0 32768 i
*>6.6.6.0/24 45.4.4.4 0 65001 65003 i
R5#
//我们发现R5学习到的2.2.2.0/24的下一跳已经更改为R4 的出口45.4.4.4
6.从EBGP对等体学来的路由条目再传送给IBGP对等体,下一跳不会更改为自己的出口。
这里测试R4从eBGP对等体R5学习到的5.5.5.0/24在传递给iBGP对等体R2,下一跳是否更改
首先,我们查看R4的BGP表
R4#show ip bgp
BGP table version is 6, localrouter ID is 4.4.4.4
Status codes: s suppressed, ddamped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e -EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*>i2.2.2.0/24 24.2.2.2 0 100 0 i
*>i3.3.3.0/24 34.3.3.3 0 100 0 i
*> 4.4.4.0/24 0.0.0.0 0 32768 i
*> 5.5.5.0/24 45.4.4.5 0 0 65002 i
*> 6.6.6.0/24 46.4.4.6 0 0 65003 i
R4#
//我们发现R4学习到的5.5.5.0/24网段的下一跳IP地址是45.4.4.5
我们再来查看R2的BGP表
R2#show ip bgp
BGP table version is 4, localrouter ID is 2.2.2.2
Status codes: s suppressed, ddamped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e -EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*>i1.1.1.0/24 12.1.1.1 0 100 0 i
*> 2.2.2.0/24 0.0.0.0 0 32768 i
*>i4.4.4.0/24 24.2.2.4 0 100 0 i
* i5.5.5.0/24 45.4.4.5 0 100 0 65002 i
* i6.6.6.0/24 46.4.4.6 0 100 0 65003 i
R2#
//我们得出R2学习到的5.5.5.0/24网段,下一跳IP地址依然是为45.4.4.5,没有改变。
并且在R2的BGP中没有出现大于号(即最后路径的标记),那么R2是不会将它装入路由表的,我们查看R2的路由表
R2#show ip route bgp
1.0.0.0/24 is subnetted, 1 subnets
B 1.1.1.0 [200/0] via 12.1.1.1, 00:20:10
4.0.0.0/24 is subnetted, 1 subnets
B 4.4.4.0 [200/0] via 24.2.2.4, 00:18:18
R2#
//我们发现R2并没有将5.5.5.0/24网段装入路由表,原因是由于在R2的BGP中对应的下一跳地址45.4.4.5所在的网段45.4.4.0/24网段,对于R2 而言不可达造成。我们再来查看R2的IGP路由表:
R2#show ip route
Codes: C - connected, S -static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O -OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 -OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPFexternal type 2
i - IS-IS, su - IS-IS summary, L1 -IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidatedefault, U - per-user static route
o - ODR, P - periodic downloaded staticroute
Gateway of last resort is notset
34.0.0.0/24 is subnetted, 1 subnets
O 34.3.3.0 [110/128] via 24.2.2.4, 00:19:55,Serial1/0
1.0.0.0/24 is subnetted, 1 subnets
B 1.1.1.0 [200/0] via 12.1.1.1, 00:20:02
2.0.0.0/24 is subnetted, 1 subnets
C 2.2.2.0 is directly connected, Loopback0
4.0.0.0/24 is subnetted, 1 subnets
B 4.4.4.0 [200/0] via 24.2.2.4, 00:18:10
20.0.0.0/24 is subnetted, 1 subnets
C 20.20.20.0 is directly connected,Loopback10
24.0.0.0/24 is subnetted, 1 subnets
C 24.2.2.0 is directly connected,Serial1/0
40.0.0.0/24 is subnetted, 1 subnets
O 40.40.40.0 [110/65] via 24.2.2.4, 00:19:55,Serial1/0
10.0.0.0/24 is subnetted, 1 subnets
O 10.10.10.0 [110/65] via 12.1.1.1,00:19:55, Serial1/1
12.0.0.0/24 is subnetted, 1 subnets
C 12.1.1.0 is directly connected,Serial1/1
13.0.0.0/24 is subnetted, 1 subnets
O 13.1.1.0 [110/128] via 12.1.1.1,00:19:55, Serial1/1
30.0.0.0/24 is subnetted, 1 subnets
O 30.30.30.0 [110/129] via 12.1.1.1,00:19:55, Serial1/1
[110/129] via 24.2.2.4,00:19:55, Serial1/0
R2#
//我们发现R2确实没有对应的45.4.4.0/24网段的路由在IGP路由表中。
补充:如果想让R2将学习到的5.5.5.0/24,装入对应的路由表中,我们必须满足下一跳可达,这里可以用静态路由、重发布IGP、next-hop-self等完成可达。
7.从EBGP对等体学来的路由条目,再传送给EBGP路由器,下一跳更改为自己的出口。
这里我们测试R5从eBGP对等体R4学习到R6的6.6.6.0/24网段,下一跳是否会更改
首先,我们查看R4 的BGP表
R4#show ip bgp
BGP table version is 6, localrouter ID is 4.4.4.4
Status codes: s suppressed, ddamped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e -EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*>i2.2.2.0/24 24.2.2.2 0 100 0 i
*>i3.3.3.0/24 34.3.3.3 0 100 0 i
*> 4.4.4.0/24 0.0.0.0 0 32768 i
*> 5.5.5.0/24 45.4.4.5 0 0 65002 i
*> 6.6.6.0/24 46.4.4.6 0 0 65003 i
R4#
//我们得出R4学习到R6的6.6.6.0/24网段,下一跳为R6的出口IP地址46.4.4.6
然后我们查看R5的BGP表
R5#show ip bgp
BGP table version is 6, localrouter ID is 5.5.5.5
Status codes: s suppressed, ddamped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e -EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 2.2.2.0/24 45.4.4.4 0 65001 i
*> 3.3.3.0/24 45.4.4.4 0 65001 i
*> 4.4.4.0/24 45.4.4.4 0 0 65001 i
*> 5.5.5.0/24 0.0.0.0 0 32768 i
*> 6.6.6.0/24 45.4.4.4 0 65001 65003 i
R5#
//我们发现R5学习到的6.6.6.0/24网段,下一跳变更为R4 的出口IP地址45.4.4.4
补充:此时我们发现整个网络没有收敛,这是由于BGP路由传递原则造成,这里可以采用Full-Mesh、RR等解决方案来完成收敛。
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原文:http://8748667.blog.51cto.com/8738667/1395784