IP : Integrated Intermediate System-to-Intermediate System (IS-IS)

IS-IS 网络类型和帧中继接口

2015 年 8 月 28 日 - 机器翻译
其他版本: PDFpdf | 英语 (2015 年 4 月 22 日) | 反馈


目录


简介

在中间系统对中间系统(IS-IS)协议,有两种网络类型:点到点和广播。不同于开放最短路径优先(OSPF)协议, IS-IS没有其他网络类型类似非广播和点对多点。对于每种网络类型,不同种IS-IS hello (IIH)数据包被交换设立邻接。在点对点网络,点对点IIH交换;并且在广播网络(例如LAN), 1级或2级LAN IIH交换。运行IS-IS的帧中继网络可以配置属于到这些网络类型之一,根据是可用的在路由器之间通过网云连接的种类(充分地网状连接,部分地网状连接或者星型网)。本文在这种情况下提供网络类型配置不匹配的示例,并且显示如何诊断和解决问题。

先决条件

要求

本文档的读者应掌握以下这些主题的相关知识:

  • 配置帧中继

  • 配置集成IS-IS

使用的组件

本文档不限于特定的软件和硬件版本。

在本文显示的输出根据这些软件和硬件版本:

  • Cisco 2500 系列路由器

  • Cisco IOS 软件版本12.2(27)

本文档中的信息都是基于特定实验室环境中的设备编写的。本文档中使用的所有设备最初均采用原始(默认)配置。如果您使用的是真实网络,请确保您已经了解所有命令的潜在影响。

规则

有关文档规则的详细信息,请参阅 Cisco 技术提示规则

正确配置示例

IS-IS相似地对待多点serial interfaces和sub-interface对待广播接口,但是对待点对点子接口,好象附加对点对点网络。例如,在此部分的网络示例拓扑里,三充分地网状连接的路由器之间的广域网多点连接对待正如LAN连接。和在LAN, 1级或2级LAN IIH交换在他们之间,并且指定中间系统(DIS)选择。

在此拓扑示例方面,所有三路由器连接对在点到多点接口或sub-interface的帧中继网云。主接口默认情况下(类似在路由器的在路由器G)的Serial1 E和Serial0多点。路由器H和F有点对点连接通过点对点子接口,并且他们使用点对点IIH。

/image/gif/paws/13794/isis-frint.gif

这些是在此拓扑示例方面使用的路由器配置:

路由器 E
clns routing
!
interface Serial1
 ip address 10.10.10.1 255.255.255.0
 ip router isis
 encapsulation frame-relay
 clns router isis
 frame-relay map clns 123 broadcast
 frame-relay map clns 121 broadcast
 frame-relay map ip 10.10.10.3 121 broadcast
 frame-relay map ip 10.10.10.4 123 broadcast
 frame-relay lmi-type ansi
!
router isis
 net 49.0001.1111.1111.1111.00
 is-type level-1

路由器G
clns routing
!
interface Serial0
 ip address 10.10.10.3 255.255.255.0
 ip router isis
 encapsulation frame-relay
 clns router isis
 frame-relay map clns 112 broadcast
 frame-relay map clns 113 broadcast
 frame-relay map ip 10.10.10.1 112 broadcast
 frame-relay map ip 10.10.10.4 113 broadcast
 frame-relay lmi-type ansi
!
router isis
 net 49.0001.3333.3333.3333.00
 is-type level-1

路由器H
clns routing
!
interface Serial0
 no ip address
 no ip directed-broadcast
 no ip mroute-cache
 encapsulation frame-relay
 frame-relay lmi-type ansi
!
interface Serial0.1 multipoint
 ip address 10.10.10.4 255.255.255.0
 no ip directed-broadcast
 ip router isis
 clns router isis
 frame-relay map clns 132 broadcast
 frame-relay map clns 131 broadcast
 frame-relay map ip 10.10.10.1 132 broadcast
 frame-relay map ip 10.10.10.3 131 broadcast
!
interface Serial0.2 point-to-point
 ip address 10.20.20.4 255.255.255.0
 no ip directed-broadcast
 ip router isis
 clns router isis
 frame-relay interface-dlci 130
!
router isis
 net 49.0001.4444.4444.4444.00
 is-type level-1

路由器 F
clns routing
!
interface Serial2
 no ip address
 no ip directed-broadcast
 encapsulation frame-relay
 frame-relay lmi-type ansi
!
interface Serial2.1 point-to-point
 ip address 10.20.20.2 255.255.255.0
 no ip directed-broadcast
 ip router isis
 clns router isis
 frame-relay interface-dlci 103
!
router isis
 net 49.0001.2222.2222.2222.00
 is-type level-1

发出show clns neighborsshow isis databaseshow isis database详细信息on命令其中任一mesh的路由器,观察IS-IS配置的作用在多点WAN连接的。这是从show clns neighbors命令的输出在所有路由器:

Router_E# show clns neighbors

System Id      Interface   SNPA                State  Holdtime  Type Protocol
Router_G       Se1         DLCI 121            Up     29        L1   IS-IS
Router_H       Se1         DLCI 123            Up     7         L1   IS-IS

Router_G# show clns neighbors

System Id      Interface   SNPA                State  Holdtime  Type Protocol
Router_E       Se0         DLCI 112            Up     27        L1   IS-IS
Router_H       Se0         DLCI 113            Up     7         L1   IS-IS

Router_H# show clns neighbors

System Id      Interface   SNPA                State  Holdtime  Type Protocol
Router_E       Se0.1       DLCI 132            Up     23        L1   IS-IS
Router_F       Se0.2       DLCI 130            Up     25        L1   IS-IS
Router_G       Se0.1       DLCI 131            Up     28        L1   IS-IS

Router_F# show clns neighbors

System Id      Interface   SNPA                State  Holdtime  Type Protocol
Router_H       Se2.1       DLCI 103            Up     24        L1   IS-IS

show isis database的输出根据psuedonode的链路状态包(LSP) ID显示路由器H是DIS, :

Router_E# show isis database

IS-IS Level-1 Link State Database
LSPID                 LSP Seq Num  LSP Checksum  LSP Holdtime  ATT/P/OL
Router_E.00-00      * 0x00000EA6   0xA415        54            10/0/0
Router_F.00-00        0x00000DD7   0xD76E        46            0/0/0
Router_G.00-00        0x00000DE7   0x780B        40            0/0/0
Router_H.00-00        0x00000DF0   0x4346        37            0/0/0
Router_H.01-00        0x00000DD5   0xFD1F        46            0/0/0

Router_G# show isis database

IS-IS Level-1 Link State Database
LSPID                 LSP Seq Num  LSP Checksum  LSP Holdtime  ATT/P/OL
Router_E.00-00        0x00000E8F   0xD2FD        46            10/0/0
Router_F.00-00        0x00000DC0   0x0657        45            0/0/0
Router_G.00-00      * 0x00000DD0   0xA6F3        41            0/0/0
Router_H.00-00        0x00000DDA   0x6F30        42            0/0/0
Router_H.01-00        0x00000DBE   0x2C08        50            0/0/0

Router_H# show isis database

IS-IS Level-1 Link State Database
LSPID                 LSP Seq Num  LSP Checksum  LSP Holdtime  ATT/P/OL
Router_E.00-00        0x000001EC   0x1D12        44            10/0/0
Router_F.00-00        0x00000124   0x63A2        54            0/0/0
Router_G.00-00        0x00000130   0x0C3B        33            0/0/0
Router_H.00-00      * 0x0000012F   0xEA6C        42            0/0/0
Router_H.01-00      * 0x00000123   0xBA21        43            0/0/0

您能也检查LSP的详细信息由DIS生成的psuedonode的。在此输出中,伪节点LSP Router_H.01-00代表完全网格广域网,显示所有路由器附加对mesh (如伪节点LSP在LAN执行) :

Router_E# show isis database detail Router_H.01-00

IS-IS Level-1 LSP Router_H.01-00
LSPID                 LSP Seq Num  LSP Checksum  LSP Holdtime  ATT/P/OL
Router_H.01-00        0x00000DD6   0xFB20        42            0/0/0
  Metric: 0  IS Router_H.00
  Metric: 0  IS Router_E.00
  Metric: 0  IS Router_G.00

Router_G# show isis database detail Router_H.01-00

IS-IS Level-1 LSP Router_H.01-00
LSPID                 LSP Seq Num  LSP Checksum  LSP Holdtime  ATT/P/OL
Router_H.01-00        0x00000DBE   0x2C08        35            0/0/0
  Metric: 0  IS Router_H.00
  Metric: 0  IS Router_E.00
  Metric: 0  IS Router_G.00

Router_H# show isis database detail Router_H.01-00

IS-IS Level-1 LSP Router_H.01-00
LSPID                 LSP Seq Num  LSP Checksum  LSP Holdtime  ATT/P/OL
Router_H.01-00      * 0x00000126   0xB424        55            0/0/0
  Metric: 0  IS Router_H.00
  Metric: 0  IS Router_G.00
  Metric: 0  IS Router_E.00

配置不匹配问题

此部分检查一问题由于配置不匹配。路由器F Serial2.1 sub-interface从点对点更改到多点,引入在路由器F和H.之间的一问题。和在下输出中显示,路由器配置F更改,当路由器H仍然连接到路由器F通过点对点子接口时。

路由器H
clns routing
!
interface Serial0
 no ip address
 no ip directed-broadcast
 no ip mroute-cache
 encapsulation frame-relay
 frame-relay lmi-type ansi
!
interface Serial0.1 multipoint
 ip address 10.10.10.4 255.255.255.0
 no ip directed-broadcast
 ip router isis
 clns router isis
 frame-relay map clns 132 broadcast
 frame-relay map clns 131 broadcast
 frame-relay map ip 10.10.10.1 132 broadcast
 frame-relay map ip 10.10.10.3 131 broadcast
!
interface Serial0.2 point-to-point
 ip address 10.20.20.4 255.255.255.0
 no ip directed-broadcast
 ip router isis
 clns router isis
 frame-relay interface-dlci 130
!
router isis
 passive-interface Ethernet0
 net 49.0001.4444.4444.4444.00
 is-type level-1

路由器 F
clns routing
!
interface Serial2
 no ip address
 no ip directed-broadcast
 encapsulation frame-relay
 frame-relay lmi-type ansi
!
interface Serial2.1 multipoint
 ip address 10.20.20.2 255.255.255.0
 no ip directed-broadcast
 ip router isis
 clns router isis
 frame-relay interface-dlci 103
!
router isis
 net 49.0001.2222.2222.2222.00
 is-type level-1

现在,路由器H不再看到路由器F作为IS-IS邻居。

Router_H# show clns neighbors

System Id      Interface   SNPA                State  Holdtime  Type Protocol
Router_E       Se0.1       DLCI 132            Up     23        L1   IS-IS
Router_G       Se0.1       DLCI 131            Up     22        L1   IS-IS

路由器F看到路由器H作为邻居;但是而不是L1的邻接类型is IS和协议是终端系统到中间系统(ES-IS)而不是IS-IS。这意味着路由器F有一邻接问题。

Router_F# show clns neighbors

System Id      Interface   SNPA                State  Holdtime  Type Protocol
Router_H       Se2.1       DLCI 103            Up     272       IS   ES-IS

问题原因

问题围绕事实路由器F发送在其多点子接口的LAN IIH,并且路由器H发送在其点对点子接口的序列IIH。当您激活在路由器H时的debug isis adj packets,您能看到发送在Serial0.2的序列IIH。然而,您看不到所有IIH来通过Serial0.2,虽然路由器F发送在Serial2.1的LAN IIH。

Router_H# debug isis adj-packets

IS-IS Adjacency related packets debugging is on
*Mar  2 01:11:10.065: ISIS-Adj: Rec L1 IIH from DLCI 131 (Serial0.1),
cir type L1, cir id4444.01, length 1500
*Mar  2 01:11:11.421: ISIS-Adj: Sending L1 LAN IIH on Serial0.1, length 1500
*Mar  2 01:11:11.961: ISIS-Adj: Rec L1 IIH from DLCI 132 (Serial0.1),
cir type L1, cir id4444.01, length 1500
*Mar  2 01:11:14.657: ISIS-Adj: Sending L1 LAN IIH on Serial0.1, length 1500
*Mar  2 01:11:15.205: ISIS-Adj: Sending serial IIH on Serial0.2, length 1499
*Mar  2 01:11:17.237: ISIS-Adj: Sending L1 LAN IIH on Serial0.1, length 1500
*Mar  2 01:11:18.765: ISIS-Adj: Rec L1 IIH from DLCI 131 (Serial0.1),
cir type L1, cir id4444.01, length 1500
*Mar  2 01:11:20.181: ISIS-Adj: Sending L1 LAN IIH on Serial0.1, length 1500
*Mar  2 01:11:21.861: ISIS-Adj: Rec L1 IIH from DLCI 132 (Serial0.1),
cir type L1, cir id4444.01, length 1500
*Mar  2 01:11:22.717: ISIS-Adj: Sending L1 LAN IIH on Serial0.1, length 1500
*Mar  2 01:11:24.073: ISIS-Adj: Sending serial IIH on Serial0.2, length 1499
*Mar  2 01:11:25.845: ISIS-Adj: Sending L1 LAN IIH on Serial0.1, length 1500
*Mar  2 01:11:27.289: ISIS-Adj: Rec L1 IIH from DLCI 131 (Serial0.1),
cir type L1, cir id4444.01, length 1500
*Mar  2 01:11:28.637: ISIS-Adj: Sending L1 LAN IIH on Serial0.1, length 1500
*Mar  2 01:11:31.853: ISIS-Adj: Sending L1 LAN IIH on Serial0.1, length 1500
*Mar  2 01:11:31.865: ISIS-Adj: Rec L1 IIH from DLCI 132 (Serial0.1),
cir type L1, cir id4444.01, length 1500
*Mar  2 01:11:33.181: ISIS-Adj: Sending serial IIH on Serial0.2, length 1499
*Mar  2 01:11:35.165: ISIS-Adj: Sending L1 LAN IIH on Serial0.1, length 1500

当您激活在路由器F时的同样调试,您能看到路由器F接收从路由器H的序列IIH在其Serial2.1接口,但是忽略Hello。路由器F尝试发送的LAN IIH丢弃与封装故障。

Router_F# debug isis adj-packets

IS-IS Adjacency related packets debugging is on
*Mar  2 01:19:15.113: ISIS-Adj: Rec serial IIH from DLCI 103 (Serial2.1),
cir type L1, cir id 00, length 1499
*Mar  2 01:19:15.117: ISIS-Adj: Point-to-point IIH received
on multi-point interface: ignored IIH
*Mar  2 01:19:17.177: ISIS-Adj: Encapsulation failed for L1 LAN IIH on Serial2.1
*Mar  2 01:19:20.305: ISIS-Adj: Encapsulation failed for L1 LAN IIH on Serial2.1
*Mar  2 01:19:22.813: ISIS-Adj: Rec serial IIH from DLCI 103 (Serial2.1),
cir type L1, cir id 00, length 1499
*Mar  2 01:19:22.817: ISIS-Adj: Point-to-point IIH received
on multi-point interface: ignored IIH
*Mar  2 01:19:23.229: ISIS-Adj: Encapsulation failed for L1 LAN IIH on Serial2.1
*Mar  2 01:19:26.157: ISIS-Adj: Encapsulation failed for L1 LAN IIH on Serial2.1
*Mar  2 01:19:28.825: ISIS-Adj: Encapsulation failed for L1 LAN IIH on Serial2.1
*Mar  2 01:19:30.833: ISIS-Adj: Rec serial IIH from DLCI 103 (Serial2.1),
cir type L1, cir id 00, length 1499
*Mar  2 01:19:30.837: ISIS-Adj: Point-to-point IIH received
on multi-point interface: ignored IIH
*Mar  2 01:19:31.849: ISIS-Adj: Encapsulation failed for L1 LAN IIH on Serial2.1
*Mar  2 01:19:34.929: ISIS-Adj: Encapsulation failed for L1 LAN IIH on Serial2.1
*Mar  2 01:19:38.029: ISIS-Adj: Encapsulation failed for L1 LAN IIH on Serial2.1

这是什么的分析发生在路由器F和H之间,当链路类型不匹配时:

  • LAN邻接使用握手,导致三可能的状态之一:DOWN, INIT或者向上。

  • 有1级的IIH封装故障出站从在Serial2.1 sub-interface的路由器F,因为没有—在多点子接口下—一frame-relay map clns命令转发IS-IS PDU。

  • 路由器H不接收从路由器F的任何LAN IIH,因为路由器F有封装故障,当发送他们时。

  • 路由器F看到来自路由器H的序列IIH,但是忽略Hello,因为接收在多点子接口的点到点Hello。路由器F检测有事未命中或错误在从路由器H的IIH,因此路由器F创建LAN邻接,但是考虑它通过ES-IS了解,而不是从与IS-IS的一L1类型邻接。

解决方案

解决方案将保证链路的两边点到点或多点。在这种情况下,请更改路由器F Serial2.1 sub-interface回到点对点,匹配在路由器H. Serial0.2接口配置的那。在更改,摆动接口后。

下debug输出显示发生了什么,在您做变动后,并且在路由器F的Serial2接口拍动。现在路由器F能发送,并且接收在其Serial2.1的序列IIH请建立接口。

Router_F# debug isis adj-packets

*Mar  2 04:32:37.276: %LINK-5-CHANGED: Interface Serial2,
changed state to administratively down
*Mar  2 04:32:38.316: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial2,
changed state to down
*Mar  2 04:32:45.868: %LINK-3-UPDOWN: Interface Serial2, changed state to up
*Mar  2 04:32:46.868: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial2,
changed state to up
*Mar  2 04:33:05.896: ISIS-Adj: Sending serial IIH on Serial2.1, length 1499
*Mar  2 04:33:13.312: ISIS-Adj: Rec serial IIH from DLCI 103 (Serial2.1),
cir type L1, cir id 00, length 1499
*Mar  2 04:33:13.316: ISIS-Adj: rcvd state DOWN, old state DOWN, new state INIT
*Mar  2 04:33:13.316: ISIS-Adj: Action = GOING UP, new type = L1
*Mar  2 04:33:13.320: ISIS-Adj: New serial adjacency
*Mar  2 04:33:13.324: ISIS-Adj: Sending serial IIH on Serial2.1, length 1499
*Mar  2 04:33:14.196: ISIS-Adj: Rec serial IIH from DLCI 103 (Serial2.1),
cir type L1, cir id 00, length 1499
*Mar  2 04:33:14.204: ISIS-Adj: rcvd state INIT, old state INIT, new state UP
*Mar  2 04:33:14.204: ISIS-Adj: Action = GOING UP, new type = L1
*Mar  2 04:33:14.208: ISIS-Adj: L1 adj count 1
*Mar  2 04:33:14.212: ISIS-Adj: Sending serial IIH on Serial2.1, length 1499
*Mar  2 04:33:15.100: ISIS-Adj: Rec serial IIH from DLCI 103 (Serial2.1),
cir type L1, cir id 00, length 1499
*Mar  2 04:33:15.100: ISIS-Adj: rcvd state UP, old state UP, new state UP
*Mar  2 04:33:15.104: ISIS-Adj: Action = ACCEPT
*Mar  2 04:33:22.924: ISIS-Adj: Rec serial IIH from DLCI 103 (Serial2.1),
cir type L1, cir id 00, length 1499
*Mar  2 04:33:22.928: ISIS-Adj: rcvd state UP, old state UP, new state UP
*Mar  2 04:33:22.932: ISIS-Adj: Action = ACCEPT

从路由器H的角度,配置是回到正常:

Router_H# show clns neighbors

System Id      Interface   SNPA                State  Holdtime  Type Protocol
Router_E       Se0.1       DLCI 132            Up     28        L1   IS-IS
Router_F       Se0.2       DLCI 130            Up     21        L1   IS-IS
Router_G       Se0.1       DLCI 131            Up     28        L1   IS-IS

debug isis adj packets命令输出也是回到正常:

Router_H# debug isis adj-packets

*Mar  2 04:40:19.376: ISIS-Adj: Sending L1 LAN IIH on Serial0.1, length 1500
*Mar  2 04:40:21.944: ISIS-Adj: Rec L1 IIH from DLCI 132 (Serial0.1),
cir type L1, cir id 4444.4444.01, length 1500
*Mar  2 04:40:22.020: ISIS-Adj: Sending L1 LAN IIH on Serial0.1, length 1500
*Mar  2 04:40:22.428: ISIS-Adj: Rec L1 IIH from DLCI 131 (Serial0.1),
cir type L1, cir id 4444.4444.01, length 1500
*Mar  2 04:40:24.740: ISIS-Adj: Sending L1 LAN IIH on Serial0.1, length 1500
*Mar  2 04:40:24.780: ISIS-Adj: Rec serial IIH from DLCI 130 (Serial0.2),
cir type L1, cir id 0ngth 1499
*Mar  2 04:40:24.784: ISIS-Adj: rcvd state UP, old state UP, new state UP
*Mar  2 04:40:24.784: ISIS-Adj: Action = ACCEPT
*Mar  2 04:40:26.068: ISIS-Adj: Sending serial IIH on Serial0.2, length 1499
*Mar  2 04:40:27.516: ISIS-Adj: Sending L1 LAN IIH on Serial0.1, length 1500
*Mar  2 04:40:30.432: ISIS-Adj: Sending L1 LAN IIH on Serial0.1, length 1500
*Mar  2 04:40:31.152: ISIS-Adj: Rec L1 IIH from DLCI 132 (Serial0.1),
cir type L1, cir id 4444.4444.01, length 1500
*Mar  2 04:40:31.540: ISIS-Adj: Rec L1 IIH from DLCI 131 (Serial0.1),
cir type L1, cir id 4444.4444.01, length 1500
*Mar  2 04:40:33.292: ISIS-Adj: Rec serial IIH from DLCI 130 (Serial0.2),
cir type L1, cir id 0ngth 1499
*Mar  2 04:40:33.296: ISIS-Adj: rcvd state UP, old state UP, new state UP
*Mar  2 04:40:33.296: ISIS-Adj: Action = ACCEPT
*Mar  2 04:40:33.664: ISIS-Adj: Sending L1 LAN IIH on Serial0.1, length 1500
*Mar  2 04:40:34.420: ISIS-Adj: Sending serial IIH on Serial0.2, length 1499
*Mar  2 04:40:36.328: ISIS-Adj: Sending L1 LAN IIH on Serial0.1, length 1500

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Document ID: 13794