© 2003, Cisco Systems, Inc. All rights reserved. 1 IGP 路由重分布.

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-3 概述在整个 IP 互联网中，如果从配置管理和故障管理的角度看，我们通常更愿意运行一种路由选择协议，而不是多种路由选择协议。然而，现代的互联网络又常常强迫我们接受多协议 IP 路由选择域这一现实。这些差异性使得向单一路由选择协议的迁移，成为一项复杂的任务。另外，多厂商环境是需要重新分配路由的另一个因素。重新分配使得 IGP 路由的动态特性和静态路由的精确控制性融合在一起。

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-5 Planning the IP Address Transition 1.Decide if the transition is happening all at once or over an extended period of time and plan accordingly. 2.Decide on the new address space to be used for the entire network. 3.Allocate address space and document address assignment. 4.Examine and plan for the effect of the address changes on the following: Secondary addresses Network statement for routing Host addressing Access lists NAT DNS

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-6 Implementing the IP-Address Transition 1.Select the router and the subnet to be transitioned. （转换的路由和路由器） 2.Assign secondary IP addresses to routers. （配置第二地址） 3.Assign new network statements to the routing process. （声明新网址） 4.Update DNS for new addresses. （更新 dns ） 5.Implement DHCP, if not already used. 6.Configure DHCP server to assign new addresses, mask, and default gateways. 7.Allow enough time for transition. 8.Change secondary IP address to primary. 9.Remove old network statements from the routing process. 10.Remove old DNS entries. 11.Migrate to new routing protocol with redistribution. （重分布路由）

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-7 Configuring a Secondary IP Address Router# show run interface Ethernet0 ip address 10.1.2.3 255.255.255.0 Router(config)# interface e0 Router(config-if)# ip address 172.17.1.3 255.255.255.240 secondary Router# show run interface Ethernet0 ip address 172.17.1.3 255.255.255.240 secondary ip address 10.1.2.3 255.255.255.0 Before: After:

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-8 Migrating to a New IP Routing Protocol Implement and test the routing solution in the lab environment. （在实验中实施） Back up the router configurations. Determine the timeline for implementing and testing the new router configuration. Identify the boundary routers where the multiple routing protocols will run. Determine which routing protocol is the core and which is the edge. Determine the directions you want to redistribute the protocols. （制定计划）

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-9 Using Multiple Routing Protocols Interim during conversion Application-specific protocols – One size does not always fit all Political boundaries – Groups that do not work well with others Mismatch between devices – Multivendor interoperability – Host-based routers

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-11 Seed Metric The first, or seed, metric for a route is derived from being directly connected to a router interface. Use the default-metric command to establish the seed metric for the route or specify the metric when redistributing. Once a compatible metric is established, the metric will increment just like any other route.

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-13 Redistribution Implementation Considerations Routing feedback – Suboptimal path selection Incompatible routing information Inconsistent convergence time

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-18 2. 配置重分布配置重分布, 易产生几种陷阱 : 路由回环, 路由信息不兼容, 收敛时间不一致 ; 因此规划设计时要注意 : 熟悉我们的网络 ; 不要重叠使用路由选择协议 ; 在存在多台边界路由器的情况下使用单向重分布 ; 在单台路由器上使用双向重分布. 缺省路由, 路由过滤器和管理距离修改等技术的组合可被用来消除路由环路. Router eigrp 24 Redistribute rip metric 10000 100 255 1 1500 Router rip Redistribute eigrp 24 metric 2 Router ospf 1 Redistribute eigrp 24 metric 100 subnets

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-19 重新分配原则： 1 ，当重新分配路由时，必须为路由分配一个接收协议可以理解的度量值。 2 ，在多种路由协议之间，需要为路由源分配管理距离；可把管理距离看作可信度的一个量度，管理距离越小，协议的可信度越高。 3 ，在从无类别路由选择协议向有类别路由选择协议重新分配时也会使用到, 仅在掩码相同的接口之间通告路由这一特性。

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-20 配置重分布的步骤： 1 ，找出将要进行重发布配置的边界路由器；其中使用命令 redistribute 指定路由源点。 2 ，选定哪个路由协议是核心或骨干协议；通常是 BGP 或 OSPF 。 3 ，必须为重新分配的路由指定度量值；如果没有指明度量值，那么重新分配到 OSPF 的路由的度量值为 20 ；而重新分配到其他协议路由度量值的缺省值为 0 ， ISIS 可以理解 0 度量，但是 RIP 不能，因为它的跳数在 1 到 16 之间； 0 度量与 IGRP 和 EIGRP 的多度量格式也不兼容；因此 RIP ， IGRP ， EIGRP 都必须为重新分配的路由分配合适的度量，否则重新分配将不能进行。

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-22 ROUTER B Router igrp 1 Redistribute ospf 1 metric 10000 100 255 1 1500 Passive-interface ethernet1 \\ 上面的配置把 OSPF 进程 1 发现的路由向 IGRP 进程 1 \\ 上面的配置把 OSPF 进程 1 发现的路由向 IGRP 进程 1 重新分配；命令的度量部分为路由分配了 IGRP 度量；按顺序，命令中各数字分别表示为：带宽 10000kbit/s ，时延 100 ；可靠性；负载； MTU Router ospf 1 Redistribute igrp 1 metric 30 metric-type 1 subnets Network 172.16.29.0 0.0.0.255 area 0 \\ 把进程 1 发现的路由重分配进入 OSPF 进程 1 \\ 把进程 1 发现的路由重分配进入 OSPF 进程 1 。重新分配使得 B 成为 OSPF 的 ASBR ，并且被重新分配的路由是作为外部路由进行通告的。命令 metric-type 部分指明了外部路由的类型为 E1 ；关键字 subnets 仅当向 OSPF 分布路由时使用，它指明了重新分配的子网细节，没有它，仅重新分配主网地址。

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-24 ROUTER B: Router rip Redistribute igrp 1 metric 5 Passive-interface S1 Network 172.16.49.0 Router igrp 1 Redistribute rip Default-metric 1000 100 255 1 1500 Network 172.16.29.0 \\ 其余见配置文件。

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-26 Router B Router ISIS Redistribute rip metric 0 metric-type internal level-2 Net 01.0001.0000.0000.0001.00 Router rip Redistribute isis level-1-2 metric 1 Passive-interface ethernet0 Network 172.16.49.0

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-27 Redistribution Supports All Protocols RtrA(config-router)# redistribute ? bgp Border Gateway Protocol (BGP) connected Connected egp Exterior Gateway Protocol (EGP) eigrp Enhanced Interior Gateway Routing Protocol (EIGRP) igrp Interior Gateway Routing Protocol (IGRP) isis ISO IS-IS iso-igrp IGRP for OSI networks mobile Mobile routes odr On Demand stub Routes ospf Open Shortest Path First (OSPF) rip Routing Information Protocol (RIP) static Static routes

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-28 Configuring Redistribution into RIP RtrA(config)# router rip RtrA(config-router)# redistribute ospf ? Process ID RtrA(config-router)# redistribute ospf 1 ? match Redistribution of OSPF routes metric Metric for redistributed routes route-map Route map reference … Default metric is infinity.

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-30 Configuring Redistribution into OSPF RtrA(config)# router ospf 1 RtrA(config-router)# redistribute eigrp ? Autonomous system number RtrA(config-router)# redistribute eigrp 100 ? metric Metric for redistributed routes metric-type OSPF/IS-IS exterior metric type for redistributed routes route-map Route map reference subnets Consider subnets for redistribution into OSPF tag Set tag for routes redistributed into OSPF … Default metric is 20.( 如不指定的话 ) Default metric type is 2.(EX1,EX2) Subnets do not redistribute by default.

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-32 Configuring Redistribution into EIGRP RtrA(config)# router eigrp 100 RtrA(config-router)# redistribute ospf ? Process ID RtrA(config-router)# redistribute ospf 1 ? match Redistribution of OSPF routes metric Metric for redistributed routes route-map Route map reference … Default metric is infinity.

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-33 Redistributing into EIGRP Bandwidth in kilobytes = 10000 Delay in 10s of microseconds = 100 Reliability = 255 (maximum) Load = 1 (minimum) MTU = 1500 bytes

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-34 Configuring Redistribution into IS-IS RtrA(config)# router isis RtrA(config-router)# redistribute eigrp 100 ? level-1 IS-IS level-1 routes only level-1-2 IS-IS level-1 and level-2 routes level-2 IS-IS level-2 routes only metric Metric for redistributed routes metric-type OSPF/IS-IS exterior metric type for redistributed routes route-map Route map reference … Routes are introduced as level 2 with a metric of 0 by default.

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-42 Route Maps Route maps are similar to a scripting language because of the following reasons( 与脚本语言相似 ): They work like a more sophisticated access list. –Top down processing( 从上到下的处理 ) –Once there is a match, leave the route map( 匹配，离开 ) Lines are sequence-numbered for easier editing. –Insertion of lines （可以自由的插入） –Deletion of lines （可以自由的删除） Route maps are named rather than numbered for easier documentation. Match criteria and set criteria can be used, similar to the if, then logic in a scripting language.

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-43 Route Map Applications Followng are the common uses of route maps: Redistribution route filtering: A more sophisticated alternative to distribute lists.( 过滤路由和修改路由参数 ) Policy-based routing( 策略路由 ): The ability to determine routing policy based on criteria other than the destination network. NAT: Defines pools of public and private address space used in translation. BGP policy implementation: The primary tool for defining BGP routing policies.( 修改 BGP 属性来使用策略 )

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-44 Route-Map Operation route-map my_bgp permit 10 :: :::: { match statements } :: :::: { set statements } route-map my_bgp deny 20 :: :::: route-map my_bgp permit 30 :: :::: A list of statements compose a route map. The list is processed top-down like an access list. The first match found for a route is applied. The sequence number is used for inserting or deleting specific route-map statements.

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-45 Route Map Operation (Cont.) The match statement may contain multiple references. （含有多个条件） Multiple match criteria in the same line uses a logical OR. At least one reference must permit the route for it to be a candidate for redistribution. Each vertical match uses a logical AND. All match statements must permit the route for it to remain a candidate for redistribution. Route-map permit or deny determines if the candidate will be redistributed.

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-46 redistribute protocol [process id] route-map map-tag router(config-router)# Allows for detailed control of routes being redistributed into a routing protocol Route Map Commands route-map map-tag [permit | deny] [sequence-number] router(config)# Defines the route-map conditions match {conditions} router(config-route-map)# Defines the conditions to match set {actions} router(config-route-map)# Defines the action to be taken on a match

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-47 The match Command router(config-route-map)# Match {options} options : ip address ip-access-list （匹配 acl 的） ip route-source ip-access-list （匹配 acl 指定的通告路由器的 ip add ） ip next-hop ip-address-list （匹配被 acl 指定下一跳路由器地址的路由） interface type number （匹配被指定下一跳接口路由的） metric metric-value （匹配度量值的） route-type [external | internal | level-1 | level-2 |local] The match commands specify criteria to be matched. The associated route-map statement permits or denies the matching routes.

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-48 The set Command router(config-route-map)# set {options} options : metric metric-value metric-type [type-1 | type-2 | internal | external] level [level-1 | level-2 | stub-area | backbone] ip next-hop next-hop-address The set commands modify matching routes. Modifies parameters in redistributed routes bgp specific options : orgin bgp-origin-code weight bgp-weight local-preference bgp-path-attributes automatic-tag

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-49 Route Maps and Redistribution Commands Router(config)# router ospf 10 Router(config-router)# redistribute rip route-map redis-rip Router(config)# router ospf 10 Router(config-router)# redistribute rip route-map redis-rip Router(config)# route-map redis-rip permit 10 match ip address 23 29 set metric 500 set metric-type type-1 route-map redis-rip deny 20 match ip address 37 route-map redis-rip permit 30 set metric 5000 set metric-type type-2 Routes matching either ACL 23 or 29 are redistributed with an OSPF cost of 500, external type 1. Routes permitted by ACL 37 are not redistributed. All other routes are redistributed with an OSPF cost metric of 5000, external type 2. Router(config)# access-list 23 permit 10.1.0.0 0.0.255.255 access-list 29 permit 172.16.1.0 0.0.0.255 access-list 37 permit 10.0.0.0 0.255.255.255

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-53 Administrative Distance Administrative distance is a way of ranking the trustworthiness of routing information. Administrative distance is expressed as an integer, from 0 to 255. Lower administrative distance is more trustworthy. For R1 to R6: – RIP (administrative distance 120) would choose R1-R4-R6 – IS-IS (administrative distance 115) would choose R1-R4-R6 – OSPF (administrative distance 110) would choose R1-R2-R3-R5-R6 – EIGRP (administrative distance 90) would choose R1-R2-R3-R5-R6

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-54 Route SourceDefault Distance Connected interface0 Static route1 EIGRP summary route 5 External BGP20 Internal EIGRP90 IGRP100 OSPF110 IS-IS115 RIPv1, RIPv2120 External EIGRP170 Internal BGP200 Unknown255 Administrative Distance

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-55 distance weight [address(ADV 路由器 ) wildcard-mask [access- list-number | name]] Router(config-router)# Used for all protocols except EIGRP and BGP redistribution Modifying Administrative Distance distance eigrp internal-distance external-distance Router(config-router)# Used for EIGRP redistribution

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-57 Example: Redistribution Using Administrative Distance (Cont.) router ospf 1 redistribute rip metric 10000 metric-type 1 subnets network 172.31.0.0 0.0.255.255 area 0 ! router rip version 2 redistribute ospf 1 metric 5 network 10.0.0.0 no auto-summary router ospf 1 redistribute rip metric 10000 metric-type 1 subnets network 172.31.3.2 0.0.0.0 area 0 ! router rip version 2 redistribute ospf 1 metric 5 network 10.0.0.0 no auto-summary Router P3R1 Router P3R2

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-59 Example: Redistribution Using Administrative Distance (Cont.) hostname P3R1 ! router ospf 1 redistribute rip metric 10000 metric-type 1 subnets network 172.31.0.0 0.0.255.255 area 0 distance 125 0.0.0.0 255.255.255.255 64 ! router rip version 2 redistribute ospf 1 metric 5 network 10.0.0.0 no auto-summary ! access-list 64 permit 10.3.1.0 access-list 64 permit 10.3.3.0 access-list 64 permit 10.3.2.0 access-list 64 permit 10.200.200.31 access-list 64 permit 10.200.200.34 access-list 64 permit 10.200.200.32 access-list 64 permit 10.200.200.33 hostname P3R2 ! router ospf 1 redistribute rip metric 10000 metric-type 1 subnets network 172.31.3.2 0.0.0.0 area 0 distance 125 0.0.0.0 255.255.255.255 64 ! router rip version 2 redistribute ospf 1 metric 5 network 10.0.0.0 no auto-summary ! access-list 64 permit 10.3.1.0 access-list 64 permit 10.3.3.0 access-list 64 permit 10.3.2.0 access-list 64 permit 10.200.200.31 access-list 64 permit 10.200.200.34 access-list 64 permit 10.200.200.32 access-list 64 permit 10.200.200.33

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-61 使用 offset-list( 偏移列表 ) 控制度量 r1(config-router)#offset-list {acl-number/ name} {in/out} {offset 量 } { interface} 这条命令指的是先检查从某接口进来（出去）的路由通告，如果存在与访问控制列表指定的地址相匹配的路由条目，则把该路由的度量值加大（ offset 量） * 只能用于距离矢量路由协议

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-62 配置练习： A C B 172.16.1.144/28 172.16.1.160/28 172.16.1.224/28 172.16.1.128/28 172.16.1.192/28 172.16.2.32/27 172.16.2.64/27 172.16.2.128/27 172.16. 1.96/27 IGRP Ospf RIPv1 Ripv1 E1 E0

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-64 配置练习： 1 Interface ethernet 0 Ip address 172.16.1.146 255.255.255.240 Interface ethernet 1 Ip address 172.16.1.98 255.255.255.240 Router rip Redistribute igrp 1 metric 1 Passive-interface ethernet 0 Network 172.16.0.0 Router igrp 1 Redistribute rip metric 10000 1000 255 1 1500 Passive-interface ethernet1 Network 172.16.0.0

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-65 配置练习： 2 Interface ethernet 0 Ip address 172.16.1.146 255.255.255.240 Interface ethernet 1 Ip address 172.16.1.98 255.255.255.240 Router ospf 1 Redistribute rip metric 50 subnets Network 172.16.1.0 0.0.0.255 area 0 Router rip Redistribute ospf 1 metric 2 Passive-interface ethernet0 Network 172.16.0.0 ip route 172.16.1.128 255.255.255.224 e0

© 2003, Cisco Systems, Inc. All rights reserved. 1 IGP 路由重分布.

Similar presentations

Presentation on theme: "© 2003, Cisco Systems, Inc. All rights reserved. 1 IGP 路由重分布."— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

© 2003, Cisco Systems, Inc. All rights reserved. 1 IGP 路由重分布.

Similar presentations

Presentation on theme: "© 2003, Cisco Systems, Inc. All rights reserved. 1 IGP 路由重分布."— Presentation transcript:

Similar presentations

About project

Feedback