IS-IS配置实验(for clns,no ip)

一、配置ISIS，接口无需配IP地址。

R3配置文件摘要：

hostname R3

!

clns routing //先全局启用CLNS路由选择

!

interface Serial1/1

no ip address

serial restart-delay 0

clns router isis //再在接口上启用CLNS路由选择

isis circuit-type level-1 //在接口中修改电路级别为L1，默认所有级别全开

!

router isis //启用ISIS路由协议，配置NET地址；NET地址由区域地址(49.0001)、系统ID(0000.0000.0003)和NSEL(00)组成

net 49.0001.0000.0000.0003.00

!

R4配置文件摘要：

hostname R4

!

clns routing

!

interface Serial1/0

no ip address

serial restart-delay 0

clns router isis

!

interface Serial1/1

no ip address

serial restart-delay 0

clns router isis

!

router isis

net 49.0001.0000.0000.0004.00

!

R5配置文件摘要：

hostname R5

!

clns routing

!

interface Serial1/0

no ip address

serial restart-delay 0

clns router isis

isis circuit-type level-2 //在接口中修改电路级别为L2，默认所有级别全开

!

router isis

net 49.0002.0000.0000.0005.00

!

-----------------------------------------------------

二、配置完成后R3 ping R5的NET地址49.0002.0000.0000.0005.00成功。

R3#show clns route

Codes: C - connected, S - static, d - DecnetIV

I - ISO-IGRP, i - IS-IS, e - ES-IS

B - BGP, b - eBGP-neighbor

C 49.0001.0000.0000.0003.00 [1/0], Local IS-IS NET

C 49.0001 [2/0], Local IS-IS Area

R3#ping 49.0002.0000.0000.0005.00

Type escape sequence to abort.

Sending 5, 100-byte CLNS Echos with timeout 2 seconds

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 864/879/920 ms

R3#

三、R3 ping R5成功了，其数据的路由过程是怎么样的呢？

（1）R3发现目标地址的前缀49.0002与自己的前缀不同，因此R3将数据流发到最近的L1/L2 ABR，即R4。R3使用L1拓扑数据库找到前往R4的最佳路径,R3没有使用目标系统ID。

R3#show isis topology

IS-IS paths to level-1 routers

System Id Metric Next-Hop Interface SNPA

R3 --

R4 10 R4 Se1/1 *HDLC*

（2）R4使用其L2拓扑数据库选取前缀49.0002的最佳下一跳，R4没有使用目标系统ID。

R4#show isis topology

IS-IS paths to level-1 routers

System Id Metric Next-Hop Interface SNPA

R3 10 R3 Se1/0 *HDLC*

R4 --

IS-IS paths to level-2 routers

System Id Metric Next-Hop Interface SNPA

R4 --

R5 10 R5 Se1/1 *HDLC*

R4#

R4#show clns route

Codes: C - connected, S - static, d - DecnetIV

I - ISO-IGRP, i - IS-IS, e - ES-IS

B - BGP, b - eBGP-neighbor

C 49.0001.0000.0000.0004.00 [1/0], Local IS-IS NET

C 49.0001 [2/0], Local IS-IS Area

i 49.0002 [110/10]

via R5, Serial1/1

R4#

（3）R5发现目标地址的前缀49.0002与自己的前缀相同，使用目标系统ID（0000.0000.0005）查找最佳路由。

四、R4和R5的debug结果

R4#debug clns packets

CLNS packets debugging is on

R4#

*Jun 18 12:39:15.659: CLNS: Forwarding packet size 105

*Jun 18 12:39:15.659: from 49.0001.0000.0000.0003.00

*Jun 18 12:39:15.659: to 49.0002.0000.0000.0005.00

*Jun 18 12:39:15.663: via R5 (Serial1/1 *HDLC*)

*Jun 18 12:39:16.139: CLNS: Forwarding packet size 142

*Jun 18 12:39:16.139: from 49.0002.0000.0000.0005.00

*Jun 18 12:39:16.139: to 49.0001.0000.0000.0003.00

*Jun 18 12:39:16.143: via R3 (Serial1/0 *HDLC*)

R4#

R5#debug clns packets

CLNS packets debugging is on

R5#

*Jun 18 12:39:16.439: CLNS: Echo PDU received on Serial1/0 len 105

from 49.0001.0000.0000.0003.00

*Jun 18 12:39:16.439: CLNS: Originating packet, size 137

*Jun 18 12:39:16.443: from 49.0002.0000.0000.0005.00

to 49.0001.0000.0000.0003.00

via 0000.0000.0004 (Serial1/0 *HDLC*)

*Jun 18 12:39:17.319: CLNS: Echo PDU received on Serial1/0 len 105

from 49.0001.0000.0000.0003.00

*Jun 18 12:39:17.319: CLNS: Originating packet, size 137

*Jun 18 12:39:17.323: from 49.0002.0000.0000.0005.00

to 49.0001.0000.0000.0003.00

via 0000.0000.0004 (Serial1/0 *HDLC*)

*Jun 18 12:39:18.183: CLNS: Echo PDU received on Serial1/0 len 105

from 49.0001.0000.0000.0003.00

*Jun 18 12:39:18.183: CLNS: Originating packet, size 137

*Jun 18 12:39:18.187: from 49.0002.0000.0000.0005.00

to 49.0001.0000.0000.0003.00

via 0000.0000.0004 (Serial1/0 *HDLC*)

*Jun 18 12:39:19.111: CLNS: Echo PDU received on Serial1/0 len 105

from 49.0001.0000.0000.0003.00

*Jun 18 12:39:19.111: CLNS: Originating packet, size 137

*Jun 18 12:39:19.115: from 49.0002.0000.0000.0005.00

to 49.0001.0000.0000.0003.00

via 0000.0000.0004 (Serial1/0 *HDLC*)

*Jun 18 12:39:19.995: CLNS: Echo PDU received on Serial1/0 len 105

from 49.0001.0000.0000.0003.00

*Jun 18 12:39:19.995: CLNS: Originating packet, size 137

*Jun 18 12:39:19.999: from 49.0002.0000.0000.0005.00

to 49.0001.0000.0000.0003.00

via 0000.0000.0004 (Serial1/0 *HDLC*)

R5#

五、比较3个路由器的拓扑表

R3#show isis topology

//只有到level-1路由器的路径。R3只开启level1，所以只能获悉当前区域(49.0001)的拓扑

IS-IS paths to level-1 routers

System Id Metric Next-Hop Interface SNPA

R3 --

R4 10 R4 Se1/1 *HDLC*

IS-IS paths to level-2 routers

System Id Metric Next-Hop Interface SNPA

R3 --

R3#

R4#show isis topology

//既有到level-1路由器的路径，也有到level-2路由器的路径

IS-IS paths to level-1 routers

System Id Metric Next-Hop Interface SNPA

R3 10 R3 Se1/0 *HDLC*

R4 --

IS-IS paths to level-2 routers

System Id Metric Next-Hop Interface SNPA

R4 --

R5 10 R5 Se1/1 *HDLC*

R4#

R5#show isis topology

//只有到level-2路由器的路径。R5开启了level2，所以可以获悉其他区域的拓扑，但前提是其他区域和R5对接的路由器的接口也开启了level2

IS-IS paths to level-1 routers

System Id Metric Next-Hop Interface SNPA

R5 --

IS-IS paths to level-2 routers

System Id Metric Next-Hop Interface SNPA

R4 10 R4 Se1/0 *HDLC*

R5 --

R5#

六、查看各路由器的clns protocol和clns路由选择表

// L1/L2 IS根据区域地址将分组转发给LI/L2或L2；在目标区域内，IS根据系统ID沿最佳路径转发分组

R3#show clns protocol

IS-IS Router:

System Id: 0000.0000.0003.00 IS-Type: level-1-2

Manual area address(es):

49.0001

Routing for area address(es):

49.0001

Interfaces supported by IS-IS:

Serial1/1 - OSI

Redistribute:

static (on by default)

Distance for L2 CLNS routes: 110

RRR level: none

Generate narrow metrics: level-1-2

Accept narrow metrics: level-1-2

Generate wide metrics: none

Accept wide metrics: none

R3#show clns route

Codes: C - connected, S - static, d - DecnetIV

I - ISO-IGRP, i - IS-IS, e - ES-IS

B - BGP, b - eBGP-neighbor

C 49.0001.0000.0000.0003.00 [1/0], Local IS-IS NET

C 49.0001 [2/0], Local IS-IS Area

R3#

----------------

R4#show clns protocol

IS-IS Router:

System Id: 0000.0000.0004.00 IS-Type: level-1-2

Manual area address(es):

49.0001

Routing for area address(es):

49.0001

Interfaces supported by IS-IS:

Serial1/0 - OSI

Serial1/1 - OSI

Redistribute:

static (on by default)

Distance for L2 CLNS routes: 110

RRR level: none

Generate narrow metrics: level-1-2

Accept narrow metrics: level-1-2

Generate wide metrics: none

Accept wide metrics: none

R4#show clns route

Codes: C - connected, S - static, d - DecnetIV

I - ISO-IGRP, i - IS-IS, e - ES-IS

B - BGP, b - eBGP-neighbor

C 49.0001.0000.0000.0004.00 [1/0], Local IS-IS NET

C 49.0001 [2/0], Local IS-IS Area

i 49.0002 [110/10]

via R5, Serial1/1

R4#

----------------

R5#show clns protocol

IS-IS Router:

System Id: 0000.0000.0005.00 IS-Type: level-1-2

Manual area address(es):

49.0002

Routing for area address(es):

49.0002

Interfaces supported by IS-IS:

Serial1/0 - OSI

Redistribute:

static (on by default)

Distance for L2 CLNS routes: 110

RRR level: none

Generate narrow metrics: level-1-2

Accept narrow metrics: level-1-2

Generate wide metrics: none

Accept wide metrics: none

R5#show clns route

Codes: C - connected, S - static, d - DecnetIV

I - ISO-IGRP, i - IS-IS, e - ES-IS

B - BGP, b - eBGP-neighbor

C 49.0002.0000.0000.0005.00 [1/0], Local IS-IS NET

C 49.0002 [2/0], Local IS-IS Area

i 49.0001 [110/10]

via R4, Serial1/0

R5#