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1、2023/11/7,1,IP路由协议（三）,NE实验室，2008西安邮电学院,2023/11/7,2,主要内容,描述OSPF多区域互联和寻址时面临的问题解释不同类型的区域,routers,和 LSA之间的区别解释 OSPF 如何支持 VLSM解释 OSPF 在多区域中如何支持路由汇总能够正确配置一个多区域的OSPF网络,2023/11/7,3,2000,Cisco Systems,Inc.,5-3,多区域OSPF创建,2023/11/7,4,维护大型 OSPF网络的问题,My routing table is too big,I am running low on memory.,The SP
2、F is running toooften for me to route.,I am only receivingLSAs,no data.,OSPF,OSPF,OSPF,OSPF,OSPF,2023/11/7,5,Area 0,Area 1,Area 2,Autonomous System,一个自治系统由多个区域组成最小化路由更新产生的业务量,解决方案:OSPF分层路由,2023/11/7,6,OSPF 多区域网络的组成成分,Routers,LSAs,Internal,ABR,ASBR,Backbone,Type 1,Type 2,Type 3/4,Type 5,Area 0I am a
3、backbone.,Area 2I am a stub.,Area 1I am standard.,Areas,2023/11/7,7,ExternalAS,OSPF路由器的类型,InternalRouters,Area 1,Area 2,Backbone Area 0,InternalRouters,2023/11/7,8,ExternalAS,OSPF路由器的类型,InternalRouters,Area 1,Area 2,Backbone/InternalRouters,Backbone Area 0,InternalRouters,2023/11/7,9,ExternalAS,OSPF
4、路由器的类型,InternalRouters,Area 1,Area 2,Backbone/InternalRouters,ABR 和BackboneRouter,Backbone Area 0,ABR 和BackboneRouter,InternalRouters,2023/11/7,10,ExternalAS,InternalRouters,Backbone/InternalRouters,ABR 和BackboneRouter,ABR 和 BackboneRouter,InternalRouters,ASBR 和Backbone Router,OSPF路由器的类型,Area 1,Area
5、 2,Backbone Area 0,2023/11/7,11,Link-State Advertisements的类型,Type 1:Router link entryType 2:Network link entryType 3 and 4:Summary link entryType 5:AS external link entry,2023/11/7,12,OSPF链路状态数据库中的LSA,Router,Area 1,Area 0,Network,Summary,External,ABR,DR,router#show ip ospf database OSPF Router with
6、ID(10.64.0.1)(Process ID 1)Router Link States(Area 1)Link ID ADV Router Age Seq#Checksum Link count10.1.2.1 10.1.2.1 651 0 x80000005 0 xD482 4 Net Link States(Area 1)Link ID ADV Router Age Seq#Checksum10.64.0.1 10.64.0.1 538 0 x80000002 0 xAD9A Summary Net Link States(Area 1)Link ID ADV Router Age S
7、eq#Checksum10.2.1.0 10.2.1.2 439 0 x80000002 0 xE6F8,ASBR,ExternalAS,2023/11/7,13,区域的类型,骨干区负责互联;它接收所有的 LSAs.,Backbone Area 0,2023/11/7,14,Stub Area,不接受外部LSAs.,区域的类型,骨干区负责互联;它接收所有的 LSAs.,Backbone Area 0,2023/11/7,15,Totally StubbyArea,不接受外部路由，也不接收 区域间汇总 LSAs.,Stub Area,不接受外部LSAs.,区域的类型,Backbone Area
8、0,骨干区负责互联;它接收所有的 LSAs.,2023/11/7,16,2000,Cisco Systems,Inc.,5-16,OSPF多区域工作原理,2023/11/7,17,多区域网络中的分组转发,BBone,Internal,Internal,ABR2,ABR1,Area 50,Data,到 ABR1,到 Backbone,到 ABR2,到 目的网络,Area 1,Area 0,2023/11/7,18,洪泛 LSUs 到多个区域,BBone,Internal,ABR2,ABR1,Internal,Type 1,Area 1,Area 0,Area 50 Stub,2023/11/7,
9、19,洪泛 LSUs 到多个区域,BBone,Internal,ABR2,ABR1,Internal,Type 3,Type 1,Type 3,Area 1,Area 0,Area 50 Stub,2023/11/7,20,Type 5,afadjfjorqpoeru39547439070713,Type 5,Default,Area 1,Area 0,BBone,Internal,ABR2,ABR1,Area 50 Stub,Internal,RIP,Type 3,Type 3,Type 1,洪泛 LSUs 到多个区域,2023/11/7,21,洪泛 LSUs 到多个区域(cont.),Ro
10、uting Table,Inter-Area Routes,Intra-Area Routes,External(Non-OSPF Routes),Area 1,Area 1,Area 0,Area 1,RIP,2023/11/7,22,2000,Cisco Systems,Inc.,5-22,Virtual Links 简介,2023/11/7,23,其它区域必须与骨干区直连Virtual links 提供一条到骨干区的路径应尽可能避免配置Virtual links,骨干区域的要求,Area 3,Area 1,Virtual Link,Transit Area,Area 3,2023/11/
11、7,24,remoterouter#show ip ospf interface ethernet 0Ethernet0 is up,line protocol is up Internet Address 10.64.0.2/24,Area 0 Process ID 1,Router ID 10.64.0.2,Network Type BROADCAST,Cost:10 Transmit Delay is 1 sec,State DR,Priority 1,配置 Virtual Links,创建 virtual link,Router(config-router)#,area area-id
12、 virtual-link router-id,2023/11/7,25,OSPF Virtual Link 配置实例,R2:router ospf 63 network 10.3.0.0 0.0.0.255 area 1 network 10.7.0.0 0.0.0.255 area 3,R1:router ospf 100network 10.2.3.0 0.0.0.255 area 0network 10.3.2.0 0.0.0.255 area 1,Router ID,Area 3,Area 0,Area 1,Router ID,R1,R2,2023/11/7,26,2000,Cisc
13、o Systems,Inc.,5-26,配置实例,2023/11/7,27,2000,Cisco Systems,Inc.,5-27,多区域OSPF 的配置,2023/11/7,28,OSPF ABR配置,E0,E0,S0,S1,A,B,C,ABR,interface Ethernet0!router ospf 77 network 10.0.0.0 0.255.255.255 area 0,Area 1,Area 0,interface Ethernet0!interface Serial0router ospf 50 network 10.2.1.2 0.0.0.0 area 1 netw
14、ork 10.64.0.2 0.0.0.0 area 0,2023/11/7,29,Default,Default,Summary,Default,Stub 和Totally Stubby 区域,Area 1Totally Stubby,Area 0,Internal,ABR2,ABR1,Area 50Stub,Summary,External,External,InternalNon-CiscoRouter,BBone,Summary,RIP,ASBR,2023/11/7,30,典型的只有一个出口点.内部不允许有ASBR不能是 骨干区0不允许Virtual links,Stub 和Total
15、ly Stubby 区域的 限制,单出口点,Area 2,R3,R4,ExternalAS,2023/11/7,31,建立一个 stub 区域指定 发往stub 区域缺省路由的cost,Router(config-router)#,area area-id stub no-summary,Router(config-router)#,area area-id default-cost cost,配置 Stub 和 Totally Stubby 区,2023/11/7,32,OSPF Stub 区配置举例,Area 0,Stub Area 2,S0,S0,E0,R3#interface Ethe
16、rnet 0interface Serial 0 router ospf 100network 192.168.14.0 0.0.0.255 area 0network 192.168.15.0 0.0.0.255 area 2area 2 stub,R4#interface Serial 0 router ospf 15network 192.168.15.0 0.0.0.255 area 2area 2 stub,ExternalAS,R4,R3,2023/11/7,33,R4#router ospf 15network 192.168.15.0 0.0.0.255 area 2area
17、2 stub,OSPF Totally Stubby 区配置,R3#router ospf 100network 192.168.14.0 0.0.0.255 area 0network 192.168.15.0 0.0.0.255 area 2area 2 stub no-summary,Area 0,S0,S0,E0,ExternalAS,R4,R3,Totally Stubby Area 2,2023/11/7,34,减小路由表的条目限制拓扑改变的影响范围减少 LSA的数目,支持 路由汇总,Area 0 Backbone,ABRs,Area 1,汇总,2023/11/7,35,支持 VL
18、SM,OSPF 携带 subnet 掩码信息使用分层地址结构,2023/11/7,36,区域间(IA)链路汇总消息携带掩码信息一项代表多个子网 subnets,使用路由汇总,B 的Routing Table,发往路由器C的LSAs,Area 1,Area 0,ABR,汇总,B,A,C,2023/11/7,37,在ABR上合并 内部路由 在 ASBR合并外部路由,Router(config-router)#,area area-id range address mask,Router(config-router)#,summary-address address mask not-adverti
19、se tag tag,配置路由汇总,2023/11/7,38,路由汇总配置举例,R2,R2#router ospf 100network 172.16.64.10.0.0.0 area 2network 172.16.127.1 0.0.0.0 area 0,255.255.255.0,Area 2,255.255.255.0,255.255.255.0,Area 1,Interface Addresses(255.255.255.0 Mask),Interface Addresses(255.255.255.0 Mask),R1,R2,Area 0,2023/11/7,39,2000,Cis
20、co Systems,Inc.,5-39,OSPF配置验证,2023/11/7,40,show ip ospf 命令,显示 自治域内的ABRs 显示 virtual link的状态显示路由器连接的每个区域的统计信息显示 OSPF 数据库的内容,show ip ospf process-id,Router#,show ip ospf virtual-links,Router#,show ip ospf database,Router#,show ip ospf border-routers,Router#,2023/11/7,41,总结,解释不同的 区域,路由器,和 LSA的区别解释 OSPF 怎样支持 VLSM?解释OSPF 区域间的路由汇总的?配置多区域 OSPF 网络验证OSPF多区域配置,2023/11/7,42,问题,1.OSPF路由器的4种类型?2.哪种路由器产生 2型LSA?3.配置一个完全 totally stubby区的优点?4.在ABR上 汇总指定区域路由信息的指令是什么?,
