提要：
Readers of this document should have knowledge of these topics:
· Configuring Frame Relay
· Configuring Integrated IS−IS
正文：
ISIS 只有两种网络类型：点到点和广播
对于每种网络类型，IS−IS Hello (IIH)包用来交换建立邻接关系。
帧中继网络上运行IS−IS根据连接的类型（全互连，部分互连，中心-轴）可以配置成以上两种中的一种。本文档将展示如何在帧中继网络上配置、诊断、修复。在FR网络下，接口运行的模式如下：
多点接口子接口、主接口 ： 广播型网络
点到点子接口 ：点到点网络
TOPO如下：
基本配置如下：
l
R1
l
R2
l
R3
l
R4
l
FR配置部分略
R1基本配置
| interface Loopback0
ip address 1.1.1.1 255.255.255.0
!
interface Serial1/0
ip address 123.1.1.1 255.255.255.0
ip router isis
encapsulation frame-relay
frame-relay map ip 123.1.1.3 103 broadcast
frame-relay map clns 103 broadcast
frame-relay map clns 102 broadcast
frame-relay map ip 123.1.1.2 102 broadcast
no frame-relay inverse-arp
!
router isis
net 10.0010.0100.1001.00
passive-interface Loopback0
|
R2基本配置
| !
interface Loopback0
ip address 2.2.2.2 255.255.255.0
!
interface Serial1/0
ip address 123.1.1.2 255.255.255.0
ip router isis
encapsulation frame-relay
serial restart-delay 0
frame-relay map ip 123.1.1.3 203 broadcast
frame-relay map clns 203 broadcast
frame-relay map clns 201 broadcast
frame-relay map ip 123.1.1.1 201 broadcast
no frame-relay inverse-arp
!
router isis
net 10.0020.0200.2002.00
passive-interface Loopback0
|
R3基本配置
| interface Loopback0
ip address 3.3.3.3 255.255.255.0
!
interface Serial1/0
no ip address
encapsulation frame-relay
no frame-relay inverse-arp
!
interface Serial1/0.34 point-to-point
ip address 34.1.1.3 255.255.255.0
ip router isis
frame-relay interface-dlci 304
! 与R4相连的子接口
（点到点子接口）
interface Serial1/0.123 multipoint
ip address 123.1.1.3 255.255.255.0
ip router isis
frame-relay map clns 302 broadcast
frame-relay map clns 301 broadcast
frame-relay map ip 123.1.1.1 301 broadcast
frame-relay map ip 123.1.1.2 302 broadcast
no frame-relay inverse-arp
!
与R1、R2相连的子接口
（多点子接口）
router isis
net 10.0030.0300.3003.00
passive-interface Loopback0
|
R4基本配置
| interface Loopback0
ip address 4.4.4.4 255.255.255.0
!
interface Serial1/0
no ip address
encapsulation frame-relay
no frame-relay inverse-arp
!
interface Serial1/0.34 point-to-point
ip address 34.1.1.4 255.255.255.0
ip router isis
frame-relay interface-dlci 403
!
router isis
net 10.0040.0400.4004.00
passive-interface Loopback0
|
测试⑴：
在R3用三种形式查看邻居关系
r3#sho isis nei
System Id
Type Interface IP Address
State Holdtime Circuit Id
r1
L1
Se1/0.123 123.1.1.1
UP
22
r3.01
r1
L2
Se1/0.123 123.1.1.1
UP
26
r3.01
r2
L1
Se1/0.123 123.1.1.2
UP
29
r3.01
r2
L2
Se1/0.123 123.1.1.2
UP
25
r3.01
r4
L1L2 Se1/0.34
34.1.1.4
UP
24
00
r3#sho clns nei
System Id
Interface
SNPA
State
Holdtime
Type Protocol
r1
Se1/0.123
DLCI 301
Up
29
L1L2 IS-IS
r2
Se1/0.123
DLCI 302
Up
28
L1L2 IS-IS
r4
Se1/0.34
DLCI 304
Up
28
L1L2 IS-IS
r3#sho clns is
System Id
Interface
State
Type Priority
Circuit Id
Format
r1
Se1/0.123
Up
L1L2 64/64
r3.01
Phase V
r2
Se1/0.123
Up
L1L2 64/64
r3.01
Phase V
r4
Se1/0.34
Up
L1L2 0 /0
00
Phase V
从第三种查看邻居关系的output可见，R1、R2、R3是在广播的网络中，并且R3成为DIS，R3、R4是在点到点的网络中。
查看伪节点LSP，r3.01-00代表fully−meshed的广域网，output表明了所有连接到mesh的路由器（就像伪节点在LAN上面的作用）
r3#sho isis database r3.01-00 de
IS-IS Level-1 LSP r3.01-00
LSPID
LSP Seq Num
LSP Checksum
LSP Holdtime
ATT/P/OL
r3.01-00
* 0x00000003
0x672D
747
0/0/0
Metric: 0
IS r3.00
Metric: 0
IS r1.00
Metric: 0
IS r2.00
IS-IS Level-2 LSP r3.01-00
LSPID
LSP Seq Num
LSP Checksum
LSP Holdtime
ATT/P/OL
r3.01-00
* 0x00000003
0x1904
603
0/0/0
Metric: 0
IS r3.00
Metric: 0
IS r1.00
Metric: 0
IS r2.00
查看R3上更新CSNP
r3#debug isis snp-packets
IS-IS CSNP/PSNP packets debugging is on
r3#
*Mar
1 01:23:10.119: ISIS-Snp: Sending L1 CSNP on Serial1/0.123
*Mar
1 01:23:10.795: ISIS-Snp: Sending L2 CSNP on Serial1/0.123
r3#
*Mar
1 01:23:18.667: ISIS-Snp: Sending L1 CSNP on Serial1/0.123
*Mar
1 01:23:18.791: ISIS-Snp: Sending L2 CSNP on Serial1/0.123
查看R3路由表
r3#sho ip route | be Ga
Gateway of last resort is not set
34.0.0.0/24 is subnetted, 1 subnets
C
34.1.1.0 is directly connected, Serial1/0.34
1.0.0.0/24 is subnetted, 1 subnets
i L1
1.1.1.0 [115/10] via 123.1.1.1, Serial1/0.123
2.0.0.0/24 is subnetted, 1 subnets
i L1
2.2.2.0 [115/10] via 123.1.1.2, Serial1/0.123
3.0.0.0/24 is subnetted, 1 subnets
C
3.3.3.0 is directly connected, Loopback0
4.0.0.0/24 is subnetted, 1 subnets
i L1
4.4.4.0 [115/10] via 34.1.1.4, Serial1/0.34
123.0.0.0/24 is subnetted, 1 subnets
C
123.1.1.0 is directly connected, Serial1/0.123
现在更改R4的接口为多点子接口
interface Serial1/0.32 multipoint
ip address 34.1.1.4 255.255.255.0
ip router isis
frame-relay map clns 403 broadcast
frame-relay map ip 34.1.1.3 403 broadcast
发现邻居形成不起来了
r4#sho clns nei
System Id
Interface
SNPA
State
Holdtime
Type Protocol
r3
Se1/0.32
DLCI 403
Up
267
IS
ES-IS
关于不能形成邻居做以下分析：
l
LAN邻接关系利用三方握手机制，三种可能的邻接状态：Up、Initializing, Down
l
R3子接口封装IIHs，因为R3接口下没有frame map
clns 命令，就不能转发IS−IS PDUs.
l
R4没有收到任何来自R3上面的LAN IIHs，因为当R3发送时，封装失败。
l
R4收到了来自R3的serial IIHs，但是R4从多点子接口收到serial IIHs，所以忽略。R4发现来自R3的IIH有些东西丢失或者错误，就不与R3形成LAN 邻接关系。
r4#debug isis adj-packets
*Mar
1 00:02:24.735: ISIS-Adj: Sending L1 LAN IIH on Serial1/0.32, length 1500
r4#
*Mar
1 00:02:27.287: ISIS-Adj: Sending L1 LAN IIH on Serial1/0.32, length 1500
r4#
*Mar
1 00:02:28.483: ISIS-Adj: Rec serial IIH from DLCI 403 (Serial1/0.32), cir type L1L2, cir id 00, length 1499
*Mar
1 00:02:28.487: ISIS-Adj: Point-to-point IIH received on multi-point interface: ignored IIH
忽略IIH，导致邻接关系起不来。
r4#
*Mar
1 00:02:30.523: ISIS-Adj: Sending L1 LAN IIH on Serial1/0.32, length 1500
解决方法，把两边都改成点到点子接口，或者都是点到多点子接口。
r3(config)#no int s1/0.34
Not all config may be removed and may reappear after reactivating the sub-interface
r3(config)#int s1/0.32 mutli
r3(config-subif)#ip add 34.1.1.3 255.255.255.0
r3(config-subif)#ip router isis
r3(config-subif)# frame-relay map clns 304 broadcast
r3(config-subif)#frame-relay map ip 34.1.1.4 304 bro
r3(config-subif)#no frame-relay inverse-arp
查看邻居关系，和debug isis adj
r4#sho clns nei
System Id
Interface
SNPA
State
Holdtime
Type Protocol
r3
Se1/0.32
DLCI 403
Up
27
L1L2 IS-IS
r4#
*Mar
1 00:10:49.095: ISIS-Adj: Sending L2 LAN IIH on Serial1/0.32, length 1500
r4#
*Mar
1 00:10:50.295: ISIS-Adj: Sending L1 LAN IIH on Serial1/0.32, length 1500
r4#
*Mar
1 00:10:52.295: ISIS-Adj: Sending L2 LAN IIH on Serial1/0.32, length 1500
*Mar
1 00:10:52.583: ISIS-Adj: Rec L2 IIH from DLCI 403 (Serial1/0.32), cir type L1L2, cir id 0040.0400.4004.01, length 1500
查看路由表，是全的
r4#sho ip route | be Ga
Gateway of last resort is not set
34.0.0.0/24 is subnetted, 1 subnets
C
34.1.1.0 is directly connected, Serial1/0.32
1.0.0.0/24 is subnetted, 1 subnets
i L1
1.1.1.0 [115/20] via 34.1.1.3, Serial1/0.32
2.0.0.0/24 is subnetted, 1 subnets
i L1
2.2.2.0 [115/20] via 34.1.1.3, Serial1/0.32
3.0.0.0/24 is subnetted, 1 subnets
i L1
3.3.3.0 [115/10] via 34.1.1.3, Serial1/0.32
4.0.0.0/24 is subnetted, 1 subnets
C
4.4.4.0 is directly connected, Loopback0
123.0.0.0/24 is subnetted, 1 subnets
i L1
123.1.1.0 [115/20] via 34.1.1.3, Serial1/0.32
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