路由协议的认识.docx
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路由协议的认识
实验拓扑:
实验配置:
实验拓扑如上图,两个路由选择域,在R2,R3上做路由的双向重分布,使每个区域的路由器都可以达到共识.
实验目的:
解决在多点重分布时出现路径的不优问题.
R2配置:
!
routerospf1
router-id2.2.2.2
log-adjacency-changes
redistributeripmetric10000metric-type1subnets
network192.1.12.00.0.0.255area0
!
routerrip
version2
redistributeospf1metric5
network2.0.0.0
network192.2.24.0
noauto-summary
!
ipclassless
noiphttpserver
!
!
R3配置:
!
routerospf1
router-id3.3.3.3
log-adjacency-changes
redistributeripmetric10000metric-type1subnets
network192.1.13.00.0.0.255area0
!
routerrip
version2
redistributeospf1metric5
network3.0.0.0
network192.2.35.0
noauto-summary
!
ipclassless
noiphttpserver
!
!
R2先双向重分布,然后R3再双向重分布.
R3路由表:
O192.1.12.0/24[110/128]via192.1.13.1,00:
03:
19,Serial1
1.0.0.0/24issubnetted,1subnets
O1.1.1.0[110/65]via192.1.13.1,00:
03:
19,Serial1
C192.1.13.0/24isdirectlyconnected,Serial1
2.0.0.0/24issubnetted,1subnets
OE12.2.2.0[110/10128]via192.1.13.1,00:
03:
19,Serial1
3.0.0.0/24issubnetted,1subnets
C3.3.3.0isdirectlyconnected,Loopback0
OE1192.2.45.0/24[110/10128]via192.1.13.1,00:
03:
19,Serial1
4.0.0.0/24issubnetted,1subnets
OE14.4.4.0[110/10128]via192.1.13.1,00:
03:
20,Serial1
5.0.0.0/24issubnetted,1subnets
OE15.5.5.0[110/10128]via192.1.13.1,00:
03:
20,Serial1
OE1192.2.24.0/24[110/10128]via192.1.13.1,00:
03:
22,Serial1
C192.2.35.0/24isdirectlyconnected,Serial0
*红色路由不优,红色条目为以下RIPv2的路由,直接通过RIP就可以到达,现在反而通过OSPF学到从RIP重分布进来的这些条目.
R2路由表:
C192.1.12.0/24isdirectlyconnected,Serial0
1.0.0.0/24issubnetted,1subnets
O1.1.1.0[110/65]via192.1.12.1,00:
00:
04,Serial0
O192.1.13.0/24[110/128]via192.1.12.1,00:
00:
04,Serial0
2.0.0.0/24issubnetted,1subnets
C2.2.2.0isdirectlyconnected,Loopback0
3.0.0.0/24issubnetted,1subnets
OE13.3.3.0[110/10128]via192.1.12.1,00:
00:
04,Serial0
R192.2.45.0/24[120/1]via192.2.24.4,00:
00:
04,Serial1
4.0.0.0/24issubnetted,1subnets
R4.4.4.0[120/1]via192.2.24.4,00:
00:
05,Serial1
5.0.0.0/24issubnetted,1subnets
R5.5.5.0[120/2]via192.2.24.4,00:
00:
05,Serial1
C192.2.24.0/24isdirectlyconnected,Serial1
OE1192.2.35.0/24[110/10128]via192.1.12.1,00:
00:
06,Serial0
*不优条目
R1路由表:
C192.1.12.0/24isdirectlyconnected,Serial0
1.0.0.0/24issubnetted,1subnets
C1.1.1.0isdirectlyconnected,Loopback0
C192.1.13.0/24isdirectlyconnected,Serial1
2.0.0.0/24issubnetted,1subnets
OE12.2.2.0[110/10064]via192.1.12.2,00:
00:
03,Serial0
3.0.0.0/24issubnetted,1subnets
OE13.3.3.0[110/10064]via192.1.13.3,00:
00:
03,Serial1
OE1192.2.45.0/24[110/10064]via192.1.12.2,00:
00:
03,Serial0
4.0.0.0/24issubnetted,1subnets
OE14.4.4.0[110/10064]via192.1.12.2,00:
00:
03,Serial0
5.0.0.0/24issubnetted,1subnets
OE15.5.5.0[110/10064]via192.1.12.2,00:
00:
04,Serial0
OE1192.2.24.0/24[110/10064]via192.1.12.2,00:
00:
04,Serial0
OE1192.2.35.0/24[110/10064]via192.1.13.3,00:
00:
14,Serial1
*R1对于下边RIPv2的路由路径没有达到负载均衡的效果
实验结论:
R2先双向重分布,把R2通过RIP学到的路由信息带进OSPF域中,R1学到R2重分布进来的RIP路由信息（OE1）,当R1把OE1路由传给R3时,此时R3本身也已有该些路由条目（R3通过RIP学到的路由信息）,R3从R1收到（OE1）与自身（RIP）相同路由条目的更新信息时,因为通过OSPF学到的路由管理距离比RIP低,故采用OE1路由,所以导致RIPv2网段的路由绕OSPF走,出现路径不优的结果.
解决办法:
R2配置:
!
routerospf1
router-id2.2.2.2
log-adjacency-changes
redistributeripmetric10000metric-type1subnets
network192.1.12.00.0.0.255area0
distance1250.0.0.0255.255.255.2551（1是调用下边的访问控制列表1）
!
routerrip
version2
redistributeospf1metric5
network2.0.0.0
network192.2.24.0
noauto-summary
!
ipclassless
noiphttpserver
!
access-list1permit192.2.0.00.0.255.255
access-list1permit2.2.2.00.0.0.255
access-list1permit3.3.3.00.0.0.255
access-list1permit4.4.4.00.0.0.255
access-list1permit5.5.5.00.0.0.255
!
R3配置:
!
routerospf1
router-id3.3.3.3
log-adjacency-changes
redistributeripmetric10000metric-type1subnets
network192.1.13.00.0.0.255area0
distance1300.0.0.0255.255.255.2551
!
routerrip
version2
redistributeospf1metric5
network3.0.0.0
network192.2.35.0
noauto-summary
!
ipclassless
noiphttpserver
!
access-list1permit192.2.0.00.0.255.255
access-list1permit2.2.2.00.0.0.255
access-list1permit3.3.3.00.0.0.255
access-list1permit4.4.4.00.0.0.255
access-list1permit5.5.5.00.0.0.255
!
对重分布进OSPF的路由条目更改其管理距离
调整后的R3路由表:
O192.1.12.0/24[110/128]via192.1.13.1,00:
05:
05,Serial1
1.0.0.0/24issubnetted,1subnets
O1.1.1.0[110/65]via192.1.13.1,00:
05:
05,Serial1
C192.1.13.0/24isdirectlyconnected,Serial1
2.0.0.0/24issubnetted,1subnets
R2.2.2.0[120/3]via192.2.35.5,00:
00:
11,Serial0
3.0.0.0/24issubnetted,1subnets
C3.3.3.0isdirectlyconnected,Loopback0
R192.2.45.0/24[120/1]via192.2.35.5,00:
00:
11,Serial0
4.0.0.0/24issubnetted,1subnets
R4.4.4.0[120/2]via192.2.35.5,00:
00:
12,Serial0
5.0.0.0/24issubnetted,1subnets
R5.5.5.0[120/1]via192.2.35.5,00:
00:
12,Serial0
R192.2.24.0/24[120/2]via192.2.35.5,00:
00:
13,Serial0
C192.2.35.0/24isdirectlyconnected,Serial0
调整后的R2路由表:
C192.1.12.0/24isdirectlyconnected,Serial0
1.0.0.0/24issubnetted,1subnets
O1.1.1.0[110/65]via192.1.12.1,00:
08:
07,Serial0
O192.1.13.0/24[110/128]via192.1.12.1,00:
08:
07,Serial0
2.0.0.0/24issubnetted,1subnets
C2.2.2.0isdirectlyconnected,Loopback0
3.0.0.0/24issubnetted,1subnets
R3.3.3.0[120/3]via192.2.24.4,00:
00:
11,Serial1
R192.2.45.0/24[120/1]via192.2.24.4,00:
00:
11,Serial1
4.0.0.0/24issubnetted,1subnets
R4.4.4.0[120/1]via192.2.24.4,00:
00:
12,Serial1
5.0.0.0/24issubnetted,1subnets
R5.5.5.0[120/2]via192.2.24.4,00:
00:
12,Serial1
C192.2.24.0/24isdirectlyconnected,Serial1
R192.2.35.0/24[120/2]via192.2.24.4,00:
00:
13,Serial1
*R2.R3的路由条目都正常了,各自使用本路由选择区域的IGP路由进行通讯
调整后的R1路由表:
C192.1.12.0/24isdirectlyconnected,Serial0
1.0.0.0/24issubnetted,1subnets
C1.1.1.0isdirectlyconnected,Loopback0
C192.1.13.0/24isdirectlyconnected,Serial1
2.0.0.0/24issubnetted,1subnets
OE12.2.2.0[110/10064]via192.1.12.2,00:
00:
00,Serial0
[110/10064]via192.1.13.3,00:
00:
00,Serial1
3.0.0.0/24issubnetted,1subnets
OE13.3.3.0[110/10064]via192.1.12.2,00:
00:
00,Serial0
[110/10064]via192.1.13.3,00:
00:
02,Serial1
OE1192.2.45.0/24[110/10064]via192.1.12.2,00:
00:
02,Serial0
[110/10064]via192.1.13.3,00:
00:
02,Serial1
4.0.0.0/24issubnetted,1subnets
OE14.4.4.0[110/10064]via192.1.12.2,00:
00:
03,Serial0
[110/10064]via192.1.13.3,00:
00:
03,Serial1
5.0.0.0/24issubnetted,1subnets
OE15.5.5.0[110/10064]via192.1.12.2,00:
00:
03,Serial0
[110/10064]via192.1.13.3,00:
00:
03,Serial1
OE1192.2.24.0/24[110/10064]via192.1.12.2,00:
00:
03,Serial0
[110/10064]via192.1.13.3,00:
00:
03,Serial1
OE1192.2.35.0/24[110/10064]via192.1.12.2,00:
00:
03,Serial0
[110/10064]via192.1.13.3,00:
00:
03,Serial1
*R1对于RIPv2路由区域的路由也都达到负载均衡的结果
实验结论:
可以修改重分布进OSPF的RIPv2路由的管理距离,以确保边界路由器选择RIPv2路由.
因为从RIPv2重分布进OSPF的路由管理距离修改为（125,130）,虽然在边界路由器上有相同的RIPv2路由条目,但RIPv2的管理距离比较小,故仍采用RIPv2的路由条目.
CCNP实验---双点双向路由重分布问题（—）
4、实验描述
该网络中，R1、R2同时运行RIP和OSPF，而R3运行OSPF，R4运行RIP，并在R3、R4上模拟两个子网。
这样R3和R4并不能互相学习到对方的子网信息，这时我们需要采用路由重分布进行解决。
实际上，我们只需在R1或者R2上部署路由重分布就可以让R3与R4互访子网，但我们为了保证网络的高可用性，让R1和R2同时进行路由重分布。
这时问题出现了，当进行R1和R2都进行双向重分布时，会出现R2（R1）访问4.4.4.0/24网络时先经过R3到R1（R2）最后才到达R4。
而不是选择最优的路径，直接到达R4。
因为在进行双点双向重分布时，R1将重分布进OSPF的4.4.4.0/24的网络传给R2，由于OSPF的AD值90>RIP的AD值120，所以R2将使用从R1学习到4.4.4.0/24的网络。
为了解决这个问题，那么可以通过修改OSPF的AD值，当R2从R1学到的关于OSPF的AD值>RIP的AD值，即可解决这个问题
5、实验步骤：
A、R1基本配置
interfaceSerial0/0
ipaddress14.0.0.1255.255.255.0
!
interfaceSerial0/1
ipaddress13.0.0.1255.255.255.0
!
B、R2基本配置
interfaceSerial0/0
ipaddress23.0.0.2255.255.255.0
!
interfaceSerial0/1
ipaddress24.0.0.2255.255.255.0
!
C、R3基本配置
interfaceLoopback0
ipaddress3.3.3.3255.255.255.0
!
interfaceSerial0/0
ipaddress23.0.0.3255.255.255.0
!
interfaceSerial0/1
ipaddress13.0.0.3255.255.255.0
!
D、R4基本配置
interfaceLoopback0
ipaddress4.4.4.4255.255.255.0
!
interfaceSerial0/0
ipaddress14.0.0.4255.255.255.0
!
interfaceSerial0/1
ipaddress24.0.0.4255.255.255.0
!
E、R1路由协议配置
routerospf1
router-id1.1.1.1
//将RIP重分布进OSPF
redistributeripsubnets
network13.0.0.00.0.0.255area0
!
routerrip
version2
//将OSPF重分布进RIP，并将metric值设为5。
如果没有设置，metric值默认是无穷大
redistributeospf1metric5
network14.0.0.0
noauto-summary
F、R2路由协议配置
routerospf1
router-id2.2.2.2
//将RIP重分布进OSPF
redistributeripsubnets
network23.0.0.00.0.0.255area0
!
routerrip
version2
//将OSPF重分布进RIP，并将metric值设为5。
如果没有设置，metric值默认是无穷大
redistributeospf1metric5
network24.0.0.0
noauto-summary
G、R3路由协议配置
routerospf1
router-id3.3.3.3
log-adjacency-changes
network3.3.3.30.0.0.0area0
network13.0.0.00.0.0.255area0
network23.0.0.00.0.0.255area0
H、R4路由协议配置
routerrip
version2
network4.0.0.0
network14.0.0.0
network24.0.0.0
noauto-summary
I、查看R2路由表
3.0.0.0/32issubnetted,1subnets
O3.3.3.3[110/65]via23.0.0.3,00:
00:
12,Serial0/0
4.0.0.0/24issubnetted,1subnets
OE24.4.4.0[110/20]via23.0.0.3,00:
00:
12,Serial0/0
23.0.0.0/24issubnetted,1subnets
C23.0.0.0isdirectlyconnected,Serial0/0
24.0.0.0/24issubnetted,1subnets
C24.0.0.0isdirectlyconnected,Serial0/1
13.0.0.0/24issubnetted,1subnets
O13.0.0.0[110/128]via23.0.0.3,00:
00:
12,Serial0/0
14.0.0.0/24issubnetted,1subnets
OE214.0.0.0[110/20]via23.0.0.3,00:
00:
14,Serial0/0
可以发现4.4.4.0/24的下一跳IP地址是23.0.0.3，这就造成R2出现非最优路径选择问题
J、修改R1和R2互相学习到AD值
因为出现次路由选择是因为R1或者R2学习到的外部路由协议AD值（RIP---120）比内部路由协议（OSPF---90）（R1、R2互相学习对方的路由）值高，所以只要将R1与R2互相学习的AD值改为121（比RIPAD大就可以）
//在R1上将从R2学习的路由AD值设为121，2.2.2.20.0.0.0为R2的router-id
distance1212.2.2.20.0.0.0
//在R2上将从R1学习的路由AD值设为121，1.1.1.10.0.0
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