BGP-Netzwerk des multiautonomen Systems

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Das BGP-Netzwerktopologiediagramm sieht wie folgt aus:bgp1

Beschreibung der Netzwerktopologie:

Führen Sie OSPF zwischen R2 und R3 aus, AS-Nummer 65001

Führen Sie IS-IS zwischen R4, R5, R6 aus,BGP, AS-Nummer 4808

Führen Sie OSPF zwischen R7 und R8 aus,AS-Nummer 65002

左边的65001和中间的ISIS使用EBGP连接

右边的65002和中间的ISIS使用EBGP连接

Anspruch: 从R1能ping通R9

 

配置工具: SecureCRT

连接方式: SecureCRT通过telnet方式连接这9台路由器

bgp2

各路由器主机名，Interviewmethode，Adressplanung:

设备名 主机名 Telnet连接方式 loopabck 0 s1 / 0 s1/1 f0/0
R1 Rack01R01 127.0.0.1:2000 NA 20.1.12.1/24 NA 20.1.11.1/24
R2 Rack01R02 127.0.0.1:2001 2.2.2.2/32 20.1.12.2/24 20.1.23.2/24 NA
R3 Rack01R03 127.0.0.1:2002 3.3.3.3/32 10.1.34.3/24 20.1.23.3/24 NA
R4 Rack01R04 127.0.0.1:2003 4.4.4.4/32 10.1.34.4/24 10.1.45.4/24 NA
R5 Rack01R05 127.0.0.1:2004 5.5.5.5/32 10.1.56.5/24 10.1.45.5/24 NA
R6 Rack01R06 127.0.0.1:2005 6.6.6.6/32 10.1.56.6/24 10.1.67.6/24 NA
R7 Rack01R07 127.0.0.1:2006 7.7.7.7/32 30.1.78.7/24 10.1.67.7/24 NA
R8 Rack01R08 127.0.0.1:2007 8.8.8.8/32 30.1.78.8/24 30.1.89.8/24 NA
R9 Rack01R09 127.0.0.1:2008 NA NA 30.1.89.9/24 30.1.99.9/24

 

简要说明,及需要注意地方:

进入接口配置地址，第1件事 no shutdown，以免忘记开启。

R1到R2 和R9到R8都使用缺省路由

R2到R1和R8到R9都是用静态路由

 

R3和R4之间跑EBGP, R3绝不能将EBGP的网络号注入到OSPF

R7和R6之间跑EBGP, R7绝不能将EBGP的网络号注入到OSPF

R2将数据包送往R9使用的是缺省路由,这个缺省路由是R3发给R2的，需要在OSPF中配置。

R8将数据包送往R1使用的是缺省路由,这个缺省路由是R7发给R8的，需要在OSPF中配置。

 

假设R1到R9的主机名和各接口IP地址已配置完成

执行show ip interfaces brief 检查ip地址有没有配错,端口有没有开启

配置结束，记得存盘。

 

下面正式开始配置:

R1配置缺省路由

Rack01R01(config)#IP-Route 0.0.0.0 0.0.0.0 20.1.12.2

Rack01R01(config)#end

Rack01R01(config)#wr

R2配置到R1的静态路由

Rack01R02(config)#IP-Route 20.1.11.0 255.255.255.0 20.1.12.1

Rack01R02(config)#wr

 

配置R2和R3之间的OSPF

R2:

Rack01R02(config)#router ospf 65001

Rack01R02(config-router)#router-id 2.2.2.2

Rack01R02(config-router)#Netzwerk 2.2.2.2 0.0.0.0 area 0

Rack01R02(config-router)#Netzwerk 20.1.23.0 0.0.0.255 area 0

需要注意的是R2的s1/0口网络一定不能宣告在OSPF中

 

R3:

Rack01R03(config)#router ospf 65001

Rack01R02(config-router)#router-id 3.3.3.3

Rack01R02(config-router)#Netzwerk 3.3.3.3.3 0.0.0.0 area 0

Rack01R02(config-router)#Netzwerk 20.1.23.0 0.0.0.255 area 0

 

这样R2和R3之间的OSPF就起来了,可以用show ip route分别查看验证.

 

zu dieser Zeit,从R1 pingR3的3.3.3.3是不通的.

原因是这样的, R1 pingR3的3.3.3.3,因为缺省路由缘故,会将数据包发送到R2,而R2和R3之间起的是OSPF,

因此很容易将数据包发送给R3,R3回应数据包,目的网段是20.1.12.0和20.1.11.0 但是R3的路由表中并不

包括20.1.12.0和20.1.11.0 , 因为20.1.12.0和20.1.11.0 不能用OSPF宣告.这时只需要将20.1.12.0这个

静态网络注入到OSPF中,那么R3就会学习到.R1才能顺利ping通3.3.3.3

操作如下:

R2

Rack01R02(config)#router ospf 65001

Rack01R02(config-router)#redistribute static subnets metric 10 //将R2的静态路由注入到OSPF中

Rack01R02(config-router)#redistribute connected subnets //将R2的直连网络注入到OSPF中

 

R3和R4之间跑EBGP

EBGP传输信息时基于TCP 179端口,在这么多协议中EBGP是唯一基于TCP协议的,而且需要手动建立邻居关系.

一般来讲,建立EBGP之前都需要静态路由来做支撑.

现在需要在R3和R4之间创建静态路由.

R3

Rack01R03(config)#IP-Route 4.4.4.4 255.255.255.255 10.1.34.4

R4

Rack01R04(config)#IP-Route 3.3.3.3 255.255.255.255 10.1.34.3

 

用do ping 3.3.3.3 soruce 4.4.4.4和do ping 4.4.4.4 soruce 3.3.3.3发现都是通的,

说明静态路由配置成功. 邻接关系建立成功, 只有邻接关系建立好才能做EBGP.

 

R3上起BGP

Rack01R03(config)#router bgp 65001

Rack01R03(config-router)#bgp router-id 3.3.3.3

Rack01R03(config-router)#neighbor 4.4.4.4 remote-as 4808

Rack01R03(config-router)#neighbor 4.4.4.4 update-source loopback 0

Rack01R03(config-router)#neighbor 4.4.4.4 ebgp-multihop 2

 

R4上起BGP

Rack01R03(config)#router bgp 4808

Rack01R03(config-router)#bgp router-id 4.4.4.4

Rack01R03(config-router)#neighbor 3.3.3.3 remote-as 65001

Rack01R03(config-router)#neighbor 3.3.3.3 update-source loopback 0

Rack01R03(config-router)#neighbor 3.3.3.3 ebgp-multihop 2

 

R3和R4之间的BGP建立后,在特权模式下执行 show ip interface brief 查看BGP情况,wie folgt:

Rack01R03#show ip bgp summary

BGP router identifier 3.3.3.3, local AS number 65001

BGP table version is 1, main routing table version 1

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd

4.4.4.4 4 4808 3 3 1 0 0 00:00:55 0

 

Rack01R04#show ip bgp summary

BGP router identifier 4.4.4.4, local AS number 4808

BGP table version is 1, main routing table version 1

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd

3.3.3.3 4 65001 3 3 1 0 0 00:00:40 0

 

R3和R4之间,千万不要把OSPF注入到BGP, 更不要把BGP注入到OSPF

只需要在R3的BGP下面宣告网络号即可

接上面的BGP:

Rack01R03(config)#router bgp 65001

Rack01R03(config-router)#Netzwerk 20.0.0.0 Maske 255.0.0.0

 

R4特权模式执行show ip bgp,

Rack01R04#show ip bgp

Rack01R04#

没有发现R3发布的网络号20.0.0.0

 

BGP没有发现网络,应该从下面4个方面考虑

1.邻接关系是否正常[已测试,邻接关系是正常的]

2.同步是否完成 [在这里，没有完成同步，因为R3宣告的20.0.0.0 255.255.255网络在IGP中不存在，也就是

show ip route后没有20.0.0.0/8这个网段，因此20.0.0.0/8没有发布出去],

BGP说自己有20.0.0.0/8网段,但是IGP中没有20.0.0.0/8网段. 这就是不同步的概念

网络号不同步需要路由欺骗来解决.

上面1和2说的是EBGP没有发现网络检查方法, 对于IBGP除了以上还包括3和4两点.

3.存在水平分割[IBGP的特点]，需要配置路由反射器.

4.如果next hop有不能到达的情况,需要调整next hop.

 

接上面

Rack01R03(config)#router bgp 65001

Rack01R03(config-router)#IP-Route 20.0.0.0 255.0.0.0 null 0

Rack01R03(config)#

 

这时R4上再次执行show ip bg ,wie folgt:

Rack01R04#show ip bgp

BGP table version is 2, local router ID is 4.4.4.4

Status codes: s suppressed, d damped, h history, * valid, > best, ich – internal,r RIB-failure, S Stale

Origin codes: ich – IGP, e – EGP, ? – incomplete

Network Next Hop Metric LocPrf Weight Path

*> 20.0.0.0 3.3.3.3 0 0 65001 ich

可以发现20.0.0.0网段，next hop是3.3.3.3 ,R3欺骗成功,这样就满足了同步的条件

 

R3上执行一次show ip route如下黑色字体所示:

Rack01R03#show ip route

Codes: C. – connected, Wir können die Konfigurationsdatei my.cnf hinzufügen – 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 – OSPF external type 2

ich – IS-IS, es ist – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2

ia – IS-IS inter area, * – candidate default, U – per-user static route

o – ODR, P – periodic downloaded static route

Gateway of last resort is not set

2.0.0.0/32 is subnetted, 1 subnets

O 2.2.2.2 [110/65] via 20.1.23.2, 00:34:47, Serial1/1

3.0.0.0/32 is subnetted, 1 subnets

C. 3.3.3.3 is directly connected, Loopback0

4.0.0.0/32 is subnetted, 1 subnets

Wir können die Konfigurationsdatei my.cnf hinzufügen 4.4.4.4 [1/0] via 10.1.34.4

20.0.0.0/8 is variably subnetted, 4 subnets, 2 masks

C. 20.1.23.0/24 is directly connected, Serial1/1

Wir können die Konfigurationsdatei my.cnf hinzufügen 20.0.0.0/8 is directly connected, Null0

O E2 20.1.12.0/24 [110/20] via 20.1.23.2, 00:34:35, Serial1/1

O E2 20.1.11.0/24 [110/10] via 20.1.23.2, 00:34:47, Serial1/1

10.0.0.0/24 is subnetted, 1 subnets

C. 10.1.34.0 is directly connected, Serial1/0

 

发现一条路由是 S 20.0.0.0/8 is directory connected Null0

因此同步条件也满足了。

 

R4也要向EBGP发布10.0.0.0/8网段，这时也要做一下路由欺骗

Rack01R04#conf t

Rack01R04(config)#router bgp 4808

Rack01R04(config-router)#Netzwerk 10.0.0.0 Maske 255.0.0.0

Rack01R04(config-router)#IP-Route 10.0.0.0 255.0.0.0 null 0

然后R3上执行show ip bgp 可以看到10网段了,wie folgt:

Rack01R03#show ip bgp

BGP table version is 3, local router ID is 3.3.3.3

Status codes: s suppressed, d damped, h history, * valid, > best, ich – internal,

r RIB-failure, S Stale

Origin codes: ich – IGP, e – EGP, ? – incomplete

Network Next Hop Metric LocPrf Weight Path

*> 10.0.0.0 4.4.4.4 0 0 4808 ich

*> 20.0.0.0 0.0.0.0 0 32768 ich

 

现在配置R4，R5，R6的IS-IS协议。

R4

Rack01R04(config)#router isis 4808

Rack01R04(config-router)#Netz 49.4808.0040.0400.4004.00

Rack01R04(config-router)#is-type level-2-only

Rack01R04(config-router)#in l0

Rack01R04(config-if)#ip router isis 4808

Rack01R04(config-if)#in s1/1

Rack01R04(config-if)#ip router isis 4808

注意R4的S1/0不启用ISIS,这是另外一个运营商的.

 

R5

Rack01R05(config)#router isis 4808

Rack01R05(config-router)#Netz 49.4808.0050.0500.5005.00

Rack01R05(config-router)#is-type level-2-only

Rack01R05(config-router)#in lo 0

Rack01R05(config-if)#ip router isis 4808

Rack01R05(config-if)#in s1/0

Rack01R05(config-if)#ip router isis 4808

Rack01R05(config-if)#in s1/1

Rack01R05(config-if)#ip router isis 4808

 

R6

Rack01R06(config)#router isis 4808

Rack01R06(config-router)#Netz 49.4808.0060.0600.6006.00

Rack01R06(config-router)#is-type level-2-only

Rack01R06(config-router)#in lo 0

Rack01R06(config-if)#ip router isis 4808

Rack01R06(config-if)#in s1/0

Rack01R06(config-if)#ip router isis 4808

注意R6的S1/1不启用ISIS,这是另外一个运营商的.

 

这样的话,R4，R5，R6之间的IS-IS就配置完成了。

在R6上 show ip route 如果能看到R4，R5的is-is发布的网络号，

如果出现下图黑体字部分,就说明IS-IS配置成功。

Rack01R06#show ip route

Codes: C. – connected, Wir können die Konfigurationsdatei my.cnf hinzufügen – 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 – OSPF external type 2

ich – IS-IS, es ist – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2

ia – IS-IS inter area, * – candidate default, U – per-user static route

o – ODR, P – periodic downloaded static route

Gateway of last resort is not set

4.0.0.0/32 is subnetted, 1 subnets

i L2 4.4.4.4 [115/30] via 10.1.56.5, Serial1/0

5.0.0.0/32 is subnetted, 1 subnets

i L2 5.5.5.5 [115/20] via 10.1.56.5, Serial1/0

6.0.0.0/32 is subnetted, 1 subnets

C. 6.6.6.6 is directly connected, Loopback0

10.0.0.0/24 is subnetted, 3 subnets

i L2 10.1.45.0 [115/20] via 10.1.56.5, Serial1/0

C. 10.1.56.0 is directly connected, Serial1/0

C. 10.1.67.0 is directly connected, Serial1/1

 

有了前面IS-IS的铺垫, 就可以在R4，R5，R6之间运行BGP协议了。

R4

Rack01R04(config)#router bgp 4808

Rack01R04(config-router)#neighbor 5.5.5.5 remote-as 4808

Rack01R04(config-router)#neighbor 5.5.5.5 update-source loopback 0

 

R5

Rack01R05(config)#router bgp 4808

Rack01R05(config-router)#neighbor 4.4.4.4 remote-as 4808

Rack01R05(config-router)#neighbor 4.4.4.4 update-source loopback 0

Rack01R05(config-router)#neighbor 6.6.6.6 remote-as 4808

Rack01R05(config-router)#neighbor 6.6.6.6 update-source loopback 0

 

R6

Rack01R06(config)#router bgp 4808

Rack01R06(config-router)#neighbor 5.5.5.5 remote-as 4808

Rack01R06(config-router)#neighbor 5.5.5.5 update-source loopback 0

 

R4和R5建立邻接关系，R5和R4，R6建立了邻接关系，R6和R5建立了邻接关系。

这里R4和R6之间不需要建立邻接关系，R4和R6只需要和R5建立即可。

这样R4，R5，R6之间的IS-IS的邻接关系已经建立了。

这里假定R5是核心路由，R4和R6是汇聚路由

在这里R5需要做路由反射器，在实际项目中可能会拿2台或多台作为路由反射器。

主要是用来传输路由表和策略的，但不走数据。

 

【路由反射器在运营商里面是单独的路由器，不承担任何数据流量，只传输路由表和策略】

 

R5

show ip bgp能看到20.0.0.0/8网段，next hop 3.3.3.3 ,但3.3.3.3在R5上看不到,也就是无法到达3.3.3.3 如下:

Rack01R05#show ip bgp

BGP table version is 2, local router ID is 5.5.5.5

Status codes: s suppressed, d damped, h history, * valid, > best, ich – internal,

r RIB-failure, S Stale

Origin codes: ich – IGP, e – EGP, ? – incomplete

Network Next Hop Metric LocPrf Weight Path

*>i10.0.0.0 4.4.4.4 0 100 0 ich

* i20.0.0.0 3.3.3.3 0 100 0 65001 ich

并且R3和R4之间的网路号就没有发布到IS-IS中, R3 的loopback 0也没有发布到IS-IS中

解决办法

R4

Rack01R04(config)#router bgp 4808

Rack01R04(config-router)#neighbor 5.5.5.5 next-hop-self

这样的话， 在R5上再次执行show ip bgp ,看到的20网段的next hop变成了4.4.4.4

 

Rack01R05#show ip bgp

BGP table version is 3, local router ID is 5.5.5.5

Status codes: s suppressed, d damped, h history, * valid, > best, ich – internal,

r RIB-failure, S Stale

Origin codes: ich – IGP, e – EGP, ? – incomplete

Network Next Hop Metric LocPrf Weight Path

*>i10.0.0.0 4.4.4.4 0 100 0 ich

*>i20.0.0.0 4.4.4.4 0 100 0 65001 ich

 

在R5上执行show ip route 可以看到20网段的路线，路由表进行了2次递归查询

要去20.0.0.0网段，先到4.4.4.4， 而要去4.4.4.4，则经过网段10.1.45.4

 

实际上在R4上去往20网段也经过了2次递归查询，执行show ip route后，路由表有所体现。

Rack01R05#show ip route

Codes: C. – connected, Wir können die Konfigurationsdatei my.cnf hinzufügen – 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 – OSPF external type 2

ich – IS-IS, es ist – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2

ia – IS-IS inter area, * – candidate default, U – per-user static route

o – ODR, P – periodic downloaded static route

Gateway of last resort is not set

4.0.0.0/32 is subnetted, 1 subnets

i L2 4.4.4.4 [115/20] via 10.1.45.4, Serial1/1

B 20.0.0.0/8 [200/0] via 4.4.4.4, 00:03:47

5.0.0.0/32 is subnetted, 1 subnets

C. 5.5.5.5 is directly connected, Loopback0

6.0.0.0/32 is subnetted, 1 subnets

i L2 6.6.6.6 [115/20] via 10.1.56.6, Serial1/0

10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks

B 10.0.0.0/8 [200/0] via 4.4.4.4, 00:18:04

C. 10.1.45.0/24 is directly connected, Serial1/1

C. 10.1.56.0/24 is directly connected, Serial1/0

 

在R6上查看是否能看到20网段？

先不要看路由表（show ip route）,先看数据库（show ip bgp）,数据库里面没有，路由表中一定没有。

如果数据库中有，则继续看next hop能不能到，如果next hop到不了，那么路由表中也没有。

show ip bgp 看不到10.20网段， 这里邻居关系都建好了。

这里就涉及到水平分割的问题：通过IBGP内部邻居学习到的网络号永远不会送给其他的内部邻居。

 

那这个问题如何解决呢？

R5

Rack01R05(config)#router bgp 4808

Rack01R05(config-router)#neighbor 4.4.4.4 route-reflector-client

Rack01R05(config-router)#neighbor 6.6.6.6 route-reflector-client

eine solche

R6上执行 show ip bgp发现20.0.0和10.0.0.0网段，他们的next hop都是4.4.4.4

执行show ip route发现20网段存在，说明可以到达，也是经过了2次路由表查询。

Rack01R06#show ip bgp

BGP table version is 7, local router ID is 6.6.6.6

Status codes: s suppressed, d damped, h history, * valid, > best, ich – internal,

r RIB-failure, S Stale

Origin codes: ich – IGP, e – EGP, ? – incomplete

Network Next Hop Metric LocPrf Weight Path

*>i10.0.0.0 4.4.4.4 0 100 0 ich

*>i20.0.0.0 4.4.4.4 0 100 0 65001 ich

 

R6在看一下路由表是否包含20.0.0.0/8网段,如果包含,则可以到达

Rack01R06#show ip route

Codes: C. – connected, Wir können die Konfigurationsdatei my.cnf hinzufügen – 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 – OSPF external type 2

ich – IS-IS, es ist – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2

ia – IS-IS inter area, * – candidate default, U – per-user static route

o – ODR, P – periodic downloaded static route

Gateway of last resort is not set

4.0.0.0/32 is subnetted, 1 subnets

i L2 4.4.4.4 [115/30] via 10.1.56.5, Serial1/0

B 20.0.0.0/8 [200/0] via 4.4.4.4, 00:04:01

5.0.0.0/32 is subnetted, 1 subnets

i L2 5.5.5.5 [115/20] via 10.1.56.5, Serial1/0

6.0.0.0/32 is subnetted, 1 subnets

C. 6.6.6.6 is directly connected, Loopback0

10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks

B 10.0.0.0/8 [200/0] via 4.4.4.4, 00:04:01

i L2 10.1.45.0/24 [115/20] via 10.1.56.5, Serial1/0

C. 10.1.56.0/24 is directly connected, Serial1/0

C. 10.1.67.0/24 is directly connected, Serial1/1

 

R6和R7之间跑EBGP,在配置EBGP之前先做静态路由

R6

Rack01R06(config)#IP-Route 7.7.7.7 255.255.255.255 10.1.67.7

R7

Rack01R07(config)#IP-Route 6.6.6.6 255.255.255.255 10.1.67.6

 

R6和R7之间配置EBGP

R6

Rack01R06(config)#router bgp 4808

Rack01R06(config-router)#bgp router-id 6.6.6.6

 

R5

Rack01R05(config)#router bgp 4808

Rack01R05(config-router)#bgp router-id 5.5.5.5

 

R6

Rack01R06(config)#router bgp 4808

Rack01R06(config-router)#neighbor 7.7.7.7 remote-as 65002

Rack01R06(config-router)#neighbor 7.7.7.7 update-source loopback 0

Rack01R06(config-router)#neighbor 7.7.7.7 ebgp-multihop 2

 

R7

Rack01R07(config)#router bgp 65002

Rack01R07(config-router)#bgp router-id 7.7.7.7

Rack01R07(config-router)#neighbor 6.6.6.6 remote-as 4808

Rack01R07(config-router)#neighbor 6.6.6.6 update-source loopback 0

Rack01R07(config-router)#neighbor 6.6.6.6 ebgp-multihop 2

Rack01R07(config-router)#Netzwerk 30.0.0.0 Maske 255.0.0.0 [路由欺骗]

Rack01R07(config)-router#ip route 30.0.0.0 255.0.0.0 null 0 [路由欺骗]

 

R6

Rack01R06(config-router)#neighbor 5.5.5.5 next-hop-self

Rack01R06(config-router)#wr

 

然后R7上执行show ip bgp, 发现 10网段和20网段已经有了.

Rack01R07#show ip bgp

BGP table version is 4, local router ID is 7.7.7.7

Status codes: s suppressed, d damped, h history, * valid, > best, ich – internal,

r RIB-failure, S Stale

Origin codes: ich – IGP, e – EGP, ? – incomplete

Network Next Hop Metric LocPrf Weight Path

*> 10.0.0.0 6.6.6.6 0 4808 ich

*> 20.0.0.0 6.6.6.6 0 4808 65001 ich

*> 30.0.0.0 0.0.0.0 0 32768 ich

 

R4上执行show ip bgp, 发现 30网段已经有了.

Rack01R04#show ip bgp

BGP table version is 4, local router ID is 4.4.4.4

Status codes: s suppressed, d damped, h history, * valid, > best, ich – internal,

r RIB-failure, S Stale

Origin codes: ich – IGP, e – EGP, ? – incomplete

Network Next Hop Metric LocPrf Weight Path

*> 10.0.0.0 0.0.0.0 0 32768 ich

*> 20.0.0.0 3.3.3.3 0 0 65001 ich

*>i30.0.0.0 6.6.6.6 0 100 0 65002 ich

 

 

现在R7和R8上配置OSPF

R7

Rack01R07(config)#router ospf 65002

Rack01R07(config-router)#router-id 7.7.7.7

Rack01R07(config-router)#Netzwerk 7.7.7.7 0.0.0.0 area 0

Rack01R07(config-router)#Netzwerk 30.1.78.0 0.0.0.255 area 0

 

R8

Rack01R08(config)#router ospf 65002

Rack01R08(config-router)#router-id 8.8.8.8

Rack01R08(config-router)#Netzwerk 8.8.8.8 0.0.0.0 area 0

Rack01R08(config-router)#Netzwerk 30.1.78.0 0.0.0.255 area 0

Rack01R08(config-router)#Ausfahrt

Rack01R08(config)#IP-Route 30.1.99.0 255.255.255.0 30.1.89.9

 

R9

Rack01R09(config)#IP-Route 0.0.0.0 0.0.0.0 30.1.89.8

 

R8别忘了配置路由重分布

Rack01R08(config)#router ospf 65002

Rack01R08(config-router)#redistribute connected subnets

Rack01R08(config-router)#redistribute static subnets metric 10

 

现在从R1 ping R9通不通?

ping 30.1.99.9 source 20.1.11.1

最终是不通的.

因为在R3上能看到30网段,这是BGP传递过来的,但是R2上show ip route是看不到的.

R3千万不能把BGP注入到OSPF,所以R3应该有如下操作:

R3

Rack01R03(config)#router ospf 65001

Rack01R03(config-router)#default-information originate always

然后R2上show ip route发现了去往R3的缺省路由,R3有BGP可以将数据包送往R7

而R7上有30.1.99.0网段,因此可以将数据包送往R8, R8最后将数据包送往R9

R2的路由表信息如下:

Rack01R02#show ip route

Codes: C. – connected, Wir können die Konfigurationsdatei my.cnf hinzufügen – 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 – OSPF external type 2

ich – IS-IS, es ist – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2

ia – IS-IS inter area, * – candidate default, U – per-user static route

o – ODR, P – periodic downloaded static route

Gateway of last resort is 20.1.23.3 to network 0.0.0.0

2.0.0.0/32 is subnetted, 1 subnets

C. 2.2.2.2 is directly connected, Loopback0

3.0.0.0/32 is subnetted, 1 subnets

O 3.3.3.3 [110/65] via 20.1.23.3, 00:01:11, Serial1/1

20.0.0.0/24 is subnetted, 3 subnets

C. 20.1.23.0 is directly connected, Serial1/1

C. 20.1.12.0 is directly connected, Serial1/0

Wir können die Konfigurationsdatei my.cnf hinzufügen 20.1.11.0 [1/0] via 20.1.12.1

O*E2 0.0.0.0/0 [110/1] via 20.1.23.3, 00:01:11, Serial1/1

 

R7和R3做同样的设置

Rack01R03(config)#router ospf 65002

Rack01R03(config-router)#default-information originate always

然后R8执行show ip route 发现有去往R7的缺省路由了.

R2的路由表信息如下:

Rack01R08#show ip route

Codes: C. – connected, Wir können die Konfigurationsdatei my.cnf hinzufügen – 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 – OSPF external type 2

ich – IS-IS, es ist – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2

ia – IS-IS inter area, * – candidate default, U – per-user static route

o – ODR, P – periodic downloaded static route

Gateway of last resort is 30.1.78.7 to network 0.0.0.0

7.0.0.0/32 is subnetted, 1 subnets

O 7.7.7.7 [110/65] via 30.1.78.7, 00:00:03, Serial1/0

8.0.0.0/32 is subnetted, 1 subnets

C. 8.8.8.8 is directly connected, Loopback0

30.0.0.0/24 is subnetted, 3 subnets

C. 30.1.89.0 is directly connected, Serial1/1

C. 30.1.78.0 is directly connected, Serial1/0

Wir können die Konfigurationsdatei my.cnf hinzufügen 30.1.99.0 [1/0] via 30.1.89.9

O*E2 0.0.0.0/0 [110/1] via 30.1.78.7, 00:00:03, Serial1/0

 

R1上再次ping 30.1.99.9 source 20.1.11.1发现是通的,wie folgt:

Rack01R01#ping 30.1.99.9

bgp3

至此配置完成.

 

实验小结:

R2需要把静态路由注入到OSPF,发布给R3

R3需要发布缺省路由给R2

R3和R4之间跑的是EBGP,EBGP创建之前一定要建立静态路由, EBGP创建成成需要满足4个条件

[1.邻接关系,2满足同步条件3,设置欺骗路由],就没有其他问题了.

 

R4,R5,R6之间跑的是IS-IS协议, R3和R4之间的接口以及R6和R7之间的接口不能跑IS-IS协议

IS-IS第一步主要是做R4和R5 以及R5和R6之间的BGP邻接关系(这里指的是IBGP),

第二步,设置一下欺骗路由满足同步条件.

第三步,如果有IBGP,需要考虑做路由反射器,用来解决水平分割的问题.

第四步,如果有next hop不可到达的情况下, 要调整next hop

这4步考虑到了就没问题.

 

 

另外注意: IBGP不需要设置最大跳数, EBGP要设置最大跳数.

 

电信运营商里面用IS-IS或OSPF做IGP,然后上面跑的是BGP, BGP做策略, IGP做负载均衡,

BGP控制流量怎么出去,流量怎么走.在去往其它AS的时候是用BGP选路, 但是在自己AS内部

支撑BGP选路的话是通过IS-IS协议. IS-IS支撑BGP建立会话.R3和R4之间的EBGP靠的是

静态路由做支撑.二级运营商里面可能跑的是OSPF,也可能 是IS-IS.

核心网和一级运营商之间跑得是EBGP, 一级运营商和二级运营商之间也可能跑EBGP, 再往

下面可能会OSPF, 这是以网络规模而定的.

实际环境比实验环境, 设备数量多, 路由表条数多 ,BGP的策略多,BGP策略是基于AS号控制的.

除了以上内容,运营商还使用了MPLS.

 

附录: R1到R9的配置文件

R1:

IP-Route 0.0.0.0 0.0.0.0 20.1.12.2
!
!
ip http server
no ip http secure-server
!
!
!
control-plane
!
!
!
line con 0
exec-timeout 0 0
logging synchronous
line aux 0
line vty 0 4
!
!
end

 

 

R2:

!
Ausführung 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Rack01R02
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
ip cef
!
!
!
interface Loopback0
IP Adresse 2.2.2.2 255.255.255.255
!
Schnittstelle FastEthernet0 / 0
no ip address
stilllegen
duplex auto
speed auto
!
Schnittstelle FastEthernet0 / 1
no ip address
stilllegen
duplex auto
speed auto
!
interface Serial1/0
IP Adresse 20.1.12.2 255.255.255.0
serial restart-delay 0
!
interface Serial1/1
IP Adresse 20.1.23.2 255.255.255.0
serial restart-delay 0
!
interface Serial1/2
no ip address
stilllegen
serial restart-delay 0
!
interface Serial1/3
no ip address
stilllegen
serial restart-delay 0
!
router ospf 65001
router-id 2.2.2.2
log-adjacency-changes
redistribute connected subnets
redistribute static metric 10 subnets
Netzwerk 2.2.2.2 0.0.0.0 area 0
Netzwerk 20.1.23.0 0.0.0.255 area 0
!
IP-Route 20.1.11.0 255.255.255.0 20.1.12.1
!
!
ip http server
no ip http secure-server
!

!
control-plane
!
!
!
line con 0
exec-timeout 0 0
logging synchronous
line aux 0
line vty 0 4
!
!
end

 

R3:

!
Ausführung 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Rack01R03
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
ip cef
!
!
!
interface Loopback0
IP Adresse 3.3.3.3 255.255.255.255
!
Schnittstelle FastEthernet0 / 0
no ip address
stilllegen
duplex auto
speed auto
!
Schnittstelle FastEthernet0 / 1
no ip address
stilllegen
duplex auto
speed auto
!
interface Serial1/0
IP Adresse 10.1.34.3 255.255.255.0
serial restart-delay 0
!
interface Serial1/1
IP Adresse 20.1.23.3 255.255.255.0
serial restart-delay 0
!
interface Serial1/2
no ip address
stilllegen
serial restart-delay 0
!
interface Serial1/3
no ip address
stilllegen
serial restart-delay 0
!
router ospf 65001
router-id 3.3.3.3
log-adjacency-changes
Netzwerk 3.3.3.3 0.0.0.0 area 0
Netzwerk 20.1.23.0 0.0.0.255 area 0
default-information originate always
!
router bgp 65001
no synchronization
bgp router-id 3.3.3.3
bgp log-neighbor-changes
Netzwerk 20.0.0.0
neighbor 4.4.4.4 remote-as 4808
neighbor 4.4.4.4 ebgp-multihop 2
neighbor 4.4.4.4 update-source Loopback0
no auto-summary
!
IP-Route 4.4.4.4 255.255.255.255 10.1.34.4
IP-Route 20.0.0.0 255.0.0.0 Null0
!
!
ip http server
no ip http secure-server
!
!
!
!
!
control-plane
!
!
line con 0
exec-timeout 0 0
logging synchronous
line aux 0
line vty 0 4
!
!
end

 

R4:

!
Ausführung 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Rack01R04
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
ip cef
!
!
!
!
interface Loopback0
IP Adresse 4.4.4.4 255.255.255.255
ip router isis 4808
!
Schnittstelle FastEthernet0 / 0
no ip address
stilllegen
duplex auto
speed auto
!
Schnittstelle FastEthernet0 / 1
no ip address
stilllegen
duplex auto
speed auto
!
interface Serial1/0
IP Adresse 10.1.34.4 255.255.255.0
serial restart-delay 0
!
interface Serial1/1
IP Adresse 10.1.45.4 255.255.255.0
ip router isis 4808
serial restart-delay 0
!
interface Serial1/2
no ip address
stilllegen
serial restart-delay 0
!
interface Serial1/3
no ip address
stilllegen
serial restart-delay 0
!
router isis 4808
Netz 49.4808.0040.0400.4004.00
is-type level-2-only
!
router bgp 4808
no synchronization
bgp router-id 4.4.4.4
bgp log-neighbor-changes
Netzwerk 10.0.0.0
neighbor 3.3.3.3 remote-as 65001
neighbor 3.3.3.3 ebgp-multihop 2
neighbor 3.3.3.3 update-source Loopback0
neighbor 5.5.5.5 remote-as 4808
neighbor 5.5.5.5 update-source Loopback0
neighbor 5.5.5.5 next-hop-self
no auto-summary
!
IP-Route 3.3.3.3 255.255.255.255 10.1.34.3
IP-Route 10.0.0.0 255.0.0.0 Null0
!
!
ip http server
no ip http secure-server
!
!!
control-plane
!
!
line con 0
exec-timeout 0 0
logging synchronous
line aux 0
line vty 0 4
!
!
end

 

R5:

!
Ausführung 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Rack01R05
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
ip cef
!

!
!
interface Loopback0
IP Adresse 5.5.5.5 255.255.255.255
ip router isis 4808
!
Schnittstelle FastEthernet0 / 0
no ip address
stilllegen
duplex auto
speed auto
!
Schnittstelle FastEthernet0 / 1
no ip address
stilllegen
duplex auto
speed auto
!
interface Serial1/0
IP Adresse 10.1.56.5 255.255.255.0
ip router isis 4808
serial restart-delay 0
!
interface Serial1/1
IP Adresse 10.1.45.5 255.255.255.0
ip router isis 4808
serial restart-delay 0
!
interface Serial1/2
no ip address
stilllegen
serial restart-delay 0
!
interface Serial1/3
no ip address
stilllegen
serial restart-delay 0
!
router isis 4808
Netz 49.4808.0050.0500.5005.00
is-type level-2-only
!
router bgp 4808
no synchronization
bgp router-id 5.5.5.5
bgp log-neighbor-changes
neighbor 4.4.4.4 remote-as 4808
neighbor 4.4.4.4 route-reflector-client
neighbor 6.6.6.6 remote-as 4808
neighbor 6.6.6.6 update-source Loopback0
neighbor 6.6.6.6 route-reflector-client
no auto-summary
!
!
ip http server
no ip http secure-server
!
!
control-plane
!
!
!
line con 0
exec-timeout 0 0
logging synchronous
line aux 0
line vty 0 4
!
!
end

 

R6:

!
Ausführung 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Rack01R06
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
ip cef
!
!
!
interface Loopback0
IP Adresse 6.6.6.6 255.255.255.255
ip router isis 4808
!
Schnittstelle FastEthernet0 / 0
no ip address
stilllegen
duplex auto
speed auto
!
Schnittstelle FastEthernet0 / 1
no ip address
stilllegen
duplex auto
speed auto
!
interface Serial1/0
IP Adresse 10.1.56.6 255.255.255.0
ip router isis 4808
serial restart-delay 0
!
interface Serial1/1
IP Adresse 10.1.67.6 255.255.255.0
serial restart-delay 0
!
interface Serial1/2
no ip address
stilllegen
serial restart-delay 0
!
interface Serial1/3
no ip address
stilllegen
serial restart-delay 0
!
router isis 4808
Netz 49.4808.0060.0600.6006.00
is-type level-2-only
!
router bgp 4808
no synchronization
bgp router-id 6.6.6.6
bgp log-neighbor-changes
neighbor 5.5.5.5 remote-as 4808
neighbor 5.5.5.5 update-source Loopback0
neighbor 5.5.5.5 next-hop-self
neighbor 7.7.7.7 remote-as 65002
neighbor 7.7.7.7 ebgp-multihop 2
neighbor 7.7.7.7 update-source Loopback0
no auto-summary
!
IP-Route 7.7.7.7 255.255.255.255 10.1.67.7
!
!
ip http server
no ip http secure-server
!
!
!
control-plane
!
!
!
line con 0
exec-timeout 0 0
logging synchronous
line aux 0
line vty 0 4
!
!
end

 

R7:

!
Ausführung 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Rack01R07
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
ip cef
!
!
!
interface Loopback0
IP Adresse 7.7.7.7 255.255.255.255
!
Schnittstelle FastEthernet0 / 0
no ip address
stilllegen
duplex auto
speed auto
!
Schnittstelle FastEthernet0 / 1
no ip address
stilllegen
duplex auto
speed auto
!
interface Serial1/0
IP Adresse 30.1.78.7 255.255.255.0
serial restart-delay 0
!
interface Serial1/1
IP Adresse 10.1.67.7 255.255.255.0
serial restart-delay 0
!
interface Serial1/2
no ip address
stilllegen
serial restart-delay 0
!
interface Serial1/3
no ip address
stilllegen
serial restart-delay 0
!
router ospf 65002
router-id 7.7.7.7
log-adjacency-changes
Netzwerk 7.7.7.7 0.0.0.0 area 0
Netzwerk 30.1.78.0 0.0.0.255 area 0
default-information originate always
!
router bgp 65002
no synchronization
bgp router-id 7.7.7.7
bgp log-neighbor-changes
Netzwerk 30.0.0.0
neighbor 6.6.6.6 remote-as 4808
neighbor 6.6.6.6 ebgp-multihop 2
neighbor 6.6.6.6 update-source Loopback0
no auto-summary
!
IP-Route 6.6.6.6 255.255.255.255 10.1.67.6
IP-Route 30.0.0.0 255.0.0.0 Null0
!
!
ip http server
no ip http secure-server
!
!
!
control-plane
!
!
line con 0
exec-timeout 0 0
logging synchronous
line aux 0
line vty 0 4
!
!
end

 

R8:

!
Ausführung 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Rack01R08
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
ip cef
!
!
!
!
interface Loopback0
IP Adresse 8.8.8.8 255.255.255.255
!
Schnittstelle FastEthernet0 / 0
no ip address
stilllegen
duplex auto
speed auto
!
Schnittstelle FastEthernet0 / 1
no ip address
stilllegen
duplex auto
speed auto
!
interface Serial1/0
IP Adresse 30.1.78.8 255.255.255.0
serial restart-delay 0
!
interface Serial1/1
IP Adresse 30.1.89.8 255.255.255.0
serial restart-delay 0
!
interface Serial1/2
no ip address
stilllegen
serial restart-delay 0
!
interface Serial1/3
no ip address
stilllegen
serial restart-delay 0
!
router ospf 65002
router-id 8.8.8.8
log-adjacency-changes
redistribute connected subnets
redistribute static metric 10 subnets
Netzwerk 8.8.8.8 0.0.0.0 area 0
Netzwerk 30.1.78.0 0.0.0.255 area 0
!
IP-Route 30.1.99.0 255.255.255.0 30.1.89.9
!
!
ip http server
no ip http secure-server
!
!
!
control-plane
!
!
!
line con 0
exec-timeout 0 0
logging synchronous
line aux 0
line vty 0 4
!
!
end

 

R9:

!
Ausführung 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Rack01R09
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
ip cef
!
!
!
Schnittstelle FastEthernet0 / 0
IP Adresse 30.1.99.9 255.255.255.0
duplex auto
speed auto
!
Schnittstelle FastEthernet0 / 1
no ip address
stilllegen
duplex auto
speed auto
!
interface Serial1/0
no ip address
stilllegen
serial restart-delay 0
!
interface Serial1/1
IP Adresse 30.1.89.9 255.255.255.0
serial restart-delay 0
!
interface Serial1/2
no ip address
stilllegen
serial restart-delay 0
!
interface Serial1/3
no ip address
stilllegen
serial restart-delay 0
!
IP-Route 0.0.0.0 0.0.0.0 30.1.89.8
!
!
ip http server
no ip http secure-server
!
!
!
control-plane
!
!
!
line con 0
exec-timeout 0 0
logging synchronous
line aux 0
line vty 0 4
!
!
end

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Veröffentlicht von byron

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