© 2003, cisco systems, inc. all rights reserved. 1 配置 is-is 中间系统

© 2003, Cisco Systems, Inc. All rights reserved. 1

配置 IS-IS 中间系统

© 2003, Cisco Systems, Inc. All rights reserved. BSCI 2.0—7-2

本节大纲 :

一，配置 ISIS 中间系统二，指定 ISIS 路由器类型；指定 ISIS 路由器接口类型； IS-IS Metric ；三， ISIS 路由汇总四，在 NBMA 中配置 ISIS ：


一 , 配置 ISIS 中间系统

Step 1: 定义区域 , 决定哪些接口要使用 ISIS.

Step 2: 启动 ISIS 路由协议 .

Clns routing

Router isis

Step 3: 在路由器上配置好 NET.

Net 49.0001.0000.0000.0002.00

Step 4: 在路由器合适接口上启动集成 ISIS.

Interface ethernet 0

Ip address 10.1.1.1 255.255.255.0

Ip router isis


Step 1: Define Area and Addressing

• Area determined by NET prefix( 区域决定前缀 )– Assign to support two-level hierarchy.

• Addressing:– IP: Plan to support summarization.

– CLNS: Prefix to denote area. System ID must be unique.


Step 2: Enable IS-IS on the Router

router isis [tag]router isis [tag]

router(config)#

• Enable the IS-IS routing protocol – tag—name for a process

• When routing of CLNS packets is also needed, use the clns routing command


Step 3: Configure the NET

net network-entity-titlenet network-entity-title

Router(config-router)#

• Configure an IS-IS NET address for the routing process


Step 4: Enable Integrated IS-IS

ip router isis [tag]clns router isis [tag]ip router isis [tag]clns router isis [tag]

router(config-if)#

• Includes an interface in an IS-IS routing process


IS-IS Configuration Steps: Simple Integrated IS-IS Example

Clns routing

router isis net 49.0001.0000.0000.0002.00!interface ethernet 0 ip address 10.1.1.1 255.255.255.0 ip router isis!interface serial 0 ip address 10.1.2.1 255.255.255.0 ip router isis

The configured router acts as IP-only L1/L2 router.


二，优化 ISIS 路由－将 R5 改成 L2-only

• Change router type on R1, R4, and R5

• Change interface levels on R2


二，优化 ISIS 路由－将 R5 改成 L2-only

没有必要要求 R2 向 R1 ， R4 发送 L2 hello 包，将 R1 ， R4 设为 L1 路由器，由于是串行链路，要求将 metric 值设为 35 （ 10/0 － 63 ）。R2 通过以太网和一台 L2 路由器互连，请将其 ISIS 链路类型设为 L2-only 。


二，指定 ISIS 路由器类型

is-type {level-1 | level-1-2 | level-2-only}is-type {level-1 | level-1-2 | level-2-only}


•Configure the IS-IS level globally on a router;

the default is L1/L2.•L1 ：路由器只学习本区域内的路由 , 也称为站点路由器，

因为它们使站点 ES 之间互联 , 并将其连接到网络的其余部分。

•L-1-2 ：这个路由器同时运行两套路由算法，既可做为站点路由器也可做为区域路由器。

•L2 ONLY ：路由器只负责区域间的路由转发，这个路由器是主干的一部分，不与同一区域中的 1 层路由器交互路由信息。


二，指定 ISIS 路由器接口类型

isis circuit-type {level-1 | level-1-2 | level-2-only}isis circuit-type {level-1 | level-1-2 | level-2-only}

Router(config-if)#

• Configure the type of adjacency on an interface; the default is L1/L2.

• \\ 在某些 L1 、 L2 层路由器上，要指定某些接口的类型；因此：• Level-1:L1 路由器；• Level-2:L2 路由器；如果邻居也配置为 LEVEL-1 且至少具有一个相

同的区域地址，则同时建立 1 层和 2 层邻居关系；如果不存在相同的区域，则建立 2 层邻居关系，这是缺省配置。

• Level-2-only: 如果其他的路由器是 2 层或者 1/2 层且接口配置为 1/2层或 2 层，建立 2 层连接。此接口如终不会建立 1 层邻居关系。


二， Change IS-IS Metric

isis metric metric {level-1 | level-2}isis metric metric {level-1 | level-2}

Router(config-if)#

• Configure the metric for an interface; the default is 10.• Metric value is from 0-63.• 如：• Interface s0• isis metric 5 level-2


Change IS-IS Metric

c2511(config)#int s0

c2511(config-if)#isis metric 5 level-2

c2511(config-if)#isis metric ?

<0-63> Default metric

c2511(config-if)#isis metric 60 ?

<0-63> Delay metric

level-1 Apply metric to level-1 links

level-2 Apply metric to level-2 links

<cr>

c2511(config-if)#isis metric 60 level-2


三， IP Summarization

summary-address prefix mask [level-1 | level-2 | level-1-2]summary-address prefix mask [level-1 | level-2 | level-1-2]


P3R1(config-router)# summary-address 10.3.2.0 255.255.254.0 level-2

• Creates summary （缩小路由表，减少 LSP 流量并防止路由波动，降低内存需求，降低 CPU 使用率）• Default is level 2Example:

• Summarizes 10.3.2.0/23 into level 2


在 NBMA 中使用点到点接口运行 ISIS：

interface s0 encapsulation frame-relay interface s0.1 point-to-point ip address 10.1.1.1 255.255.255.252 ip router isis frame-relay interface-dlci 100 interface s0.2 point-to-point ip address 10.1.1.5 255.255.255.252 ip router isis frame-relay interface-dlci 200 interface s0.3 point-to-point ip address 10.1.1.9 255.255.255.252 ip router isis frame-relay interface-dlci 300


在 NBMA 中使用多点接口运行 ISIS ：

注意：此环境要全网状结构，才能实现全网的互联。如果在实际中，只要求与中心结点相连，分支设备之间均需通信，则可使用中心 / 分支环境；这时要为中心路由器设置一个合适的优先级。C2501(config)#int s0C2501(config-if)#ip router isisC2501(config-if)#isis priority ? <0-127> Priority valueC2501(config-if)#isis priority 1C2501(config-if)#interface s0encapsulation frame-relayinterface s0.2 multipointip address 10.0.0.4 255.0.0.0ip router isisframe-relay map clns 100 broadcastframe-relay map clns 200 broadcastframe-relay map clns 300 broadcast注： CLNS ：无连接网络服务，也就是说不存在任何保证，数据可能丢失，损坏，次序错乱或者重复。


五， ISIS 排错命令：

Show ip routeShow isis route Show clns route—NET 地址Show isis database—clear isisShow isis topologyShow clns protocolShow clns neighborsShow clns interface serial 0


Example

R2# show ip protocols

Routing Protocol is "isis" Sending updates every 0 seconds Invalid after 0 seconds, hold down 0, flushed after 0 Outgoing update filter list for all interfaces is Incoming update filter list for all interfaces is Redistributing: isis Address Summarization: None Routing for Networks: Serial0 Ethernet0Routing Information Sources: Gateway Distance Last Update 11.0.0.1 115 00:11:44 13.0.0.1 115 00:11:44 14.0.0.1 115 00:11:44Distance: (default is 115)

• Displays the parameters and current state of the active routing protocol processes

Router#

show ip protocols show ip protocols


Example

R2#show ip route isis

i L1 11.0.0.0/8 [115/10] via 192.168.20.1, Serial0i L1 13.0.0.0/8 [115/10] via 192.168.220.3, Ethernet0i L1 14.0.0.0/8 [115/20] via 192.168.220.3, Ethernet0

• Displays the current state of the routing table

show ip route [address [mask]] | [protocol [process-id]]show ip route [address [mask]] | [protocol [process-id]]

router#


Is Integrated IS-IS Running

R2# show ip protocols

Routing Protocol is "isis" Sending updates every 0 seconds Invalid after 0 seconds, hold down 0, flushed after 0 Outgoing update filter list for all interfaces is Incoming update filter list for all interfaces is Redistributing: isis Address Summarization: None Routing for Networks: Serial0 Ethernet0Routing Information Sources: Gateway Distance Last Update 11.0.0.1 115 00:11:44 13.0.0.1 115 00:11:44 14.0.0.1 115 00:11:44Distance: (default is 115)

• Displays the parameters and current state of the active routing protocol processes

Router#

show ip protocols show ip protocols


Level 1 and Level 2 Topology Table

R1# show isis topology

IS-IS paths to level-1 routersSystem Id Metric Next-Hop Interface SNPAR1 --R2 10 R2 Se0 *HDLC*R4 10 R4 Se1 *HDLC*


IS-IS paths to level-1 routersSystem Id Metric Next-Hop Interface SNPAR1 10 R1 Se0 *HDLC*R2 --R4 10 R4 Se1 *HDLC*IS-IS paths to level-2 routersSystem Id Metric Next-Hop Interface SNPAR2 --R5 10 R5 Et0 0010.7bb5.9e20


Level 1 and Level 2 Topology Table


IS-IS paths to level-1 routersSystem Id Metric Next-Hop Interface SNPAR1 --R2 10 R2 Se0 *HDLC*R4 10 R4 Se1 *HDLC*


IS-IS paths to level-1 routersSystem Id Metric Next-Hop Interface SNPAR1 10 R1 Se0 *HDLC*R2 --R4 10 R4 Se1 *HDLC*IS-IS paths to level-2 routersSystem Id Metric Next-Hop Interface SNPAR2 --R5 10 R5 Et0 0010.7bb5.9e20


Intra-Area Routing on R1

R1# show clns route

CLNS Prefix Routing Table49.0001.0000.0000.0001.00, Local NET Entry

R1# show isis route

IS-IS Level-1 Routing Table - version 312System Id Next-Hop Interface SNPA Metric StateR2 R2 Se0 *HDLC* 10 Up L2-ISR4 R4 Se1 *HDLC* 10 UpR1 --Default route out of area - (via 1 L2-attached IS)System Id Next-Hop Interface SNPA Metric State

R2 Se0 *HDLC* 10 Up


Intra-Area and Inter-Area Routingon R2

R2# show clns route

CLNS Prefix Routing Table49.0001.0000.0000.0002.00, Local NET Entry49.0002 [110/10] via R5, IS-IS, Up, Ethernet049.0001 [110/0] via R2, IS-IS, Up

R2# show isis route

IS-IS Level-1 Routing Table - version 47System Id Next-Hop Interface SNPA Metric StateR4 R4 Se1 *HDLC* 10 UpR1 R1 Se0 *HDLC* 10 Up


Simple Troubleshooting:What About CLNS Protocol?

R2# show clns protocol

IS-IS Router: <Null Tag> System Id: 1921.6800.1006.00 IS-Type: level-1-2 Manual area address(es): 49.0001 Routing for area address(es): 49.0001 Interfaces supported by IS-IS: Serial0 - IP

Ethernet0 - IP Redistribute: static (on by default) Distance for L2 CLNS routes: 110 RRR level: level-1 Generate narrow metrics: level-1-2 Accept narrow metrics: level-1-2 Generate wide metrics: none Accept wide metrics: none


Are Adjacencies Established?

R2# show clns neighbors

System Id Interface SNPA State Holdtime Type ProtocolR1 Se0 *HDLC* Up 28 L1 IS-ISR5 Et0 0000.0c92.de4c Up 20 L2 IS-IS

R2# show clns interface serial 0

Serial0 is up, line protocol is up Checksums enabled, MTU 1500, Encapsulation HDLC ERPDUs enabled, min. interval 10 msec. RDPDUs enabled, min. interval 100 msec., Addr Mask enabled Congestion Experienced bit set at 4 packets CLNS fast switching disabled CLNS SSE switching disabled DEC compatibility mode OFF for this interface Next ESH/ISH in 12 seconds Routing Protocol: IS-IS Circuit Type: level-1 Interface number 0x1, local circuit ID 0x101 Level-1 Metric: 10, Priority: 64, Circuit ID: R2.00 Number of active level-1 adjacencies: 1 Next IS-IS Hello in 5 seconds


LAB:

1, 多区域 ISIS 网络2, 路由汇总3, 在 NBMA 的网络中实现 ISIS

( 关键：做点到点的子接口 ; 多点中要指定中心路由器的优先级 :isis priority 0—127, 缺省为64; 优先级为 0 的不参与 DIS 竞争 )

© 2003, cisco systems, inc. all rights reserved. 1 配置 is-is 中间系统

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