H3C IS-IS Configuration Examples

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Software version: Release 7951P01

Document version: 6W100-20200625

 

No part of this manual may be reproduced or transmitted in any form or by any means without prior written consent of New H3C Technologies Co., Ltd.

Except for the trademarks of New H3C Technologies Co., Ltd., any trademarks that may be mentioned in this document are the property of their respective owners.

 

Contents

Introduction· 1

Prerequisites· 1

Example: Configuring IS-IS·· 1

Network configuration· 1

Analysis· 2

Restrictions and guidelines· 2

Procedures· 2

Configuring Router A· 2

Configuring Router B· 3

Configuring Router C· 3

Configuring Router D·· 4

Configuring Router E· 5

Verifying the configuration· 5

Configuration files· 7

Related documentation· 9

 

Introduction

This document provides IS-IS configuration examples.

Prerequisites

The configuration examples in this document were created and verified in a lab environment, and all the devices were started with the factory default configuration. When you are working on a live network, make sure you understand the potential impact of every command on your network.

This document assumes that you have basic knowledge of IS-IS.

Example: Configuring IS-IS

Network configuration

As shown in Figure 1, the company's headquarters and the branch run IS-IS. The partner runs OSPF.

Configure the routers to meet the following requirements:

·     Reduce traffic for Router A and Router B because they have relative low performance.

·     The Marketing department can reach the Finance department, the branch, and the partner.

·     The Finance department and the branch cannot reach each other, and the branch does not have a route to the Finance department.

·     When the IS-IS process on Router C restarts, the communication is not interrupted.

Figure 1 Network diagram

 

Analysis

To meet the network requirements, you must perform the following tasks:

·     To reduce traffic for Router A and Router B, configure them as Level-1 routers to allow communication only between the Marketing department and the Finance department.

·     Configure route redistribution between IS-IS and OSPF on Router D to allow communication between the Marketing department and the partner.

·     Configure Router C to use a prefix list to advertise only network 10.100.1.0/24 to Level-2 to ensure that the branch does not have a route to the Finance department.

·     Enable IS-IS Graceful Restart (GR) on Router C to ensure that the communication is not interrupted when the IS-IS process on Router C restarts.

Restrictions and guidelines

To avoid blackhole routes, do not change the network topology during the IS-IS GR process.

Procedures

Configuring Router A

# Configure an IP address for GigabitEthernet 3/1/1.

<RouterA> system-view

[RouterA] interface gigabitethernet 3/1/1

[RouterA-GigabitEthernet3/1/1] ip address 192.168.1.1 24

[RouterA-GigabitEthernet3/1/1] quit

# Configure IP addresses for other interfaces, as shown in Figure 1. (Details not shown.)

# Configure IS-IS.

[RouterA] isis 1

[RouterA-isis-1] is-level level-1

[RouterA-isis-1] network-entity 10.1921.6800.1001.00

[RouterA-isis-1] quit

[RouterA] interface gigabitethernet 3/1/1

[RouterA–GigabitEthernet3/1/1] isis enable 1

[RouterA–GigabitEthernet3/1/1] quit

[RouterA] interface gigabitethernet 3/1/2

[RouterA–GigabitEthernet3/1/2] isis enable 1

[RouterA–GigabitEthernet3/1/2] quit

Configuring Router B

# Configure an IP address for GigabitEthernet 3/1/1.

<RouterB> system-view

[RouterB] interface gigabitethernet 3/1/1

[RouterB-GigabitEthernet3/1/1] ip address 192.168.2.1 24

[RouterB-GigabitEthernet3/1/1] quit

# Configure IP addresses for other interfaces, as shown in Figure 1. (Details not shown.)

# Configure IS-IS.

[RouterB] isis 1

[RouterB-isis-1] is-level level-1

[RouterB-isis-1] network-entity 10.1921.6800.2001.00

[RouterB-isis-1] quit

[RouterB] interface gigabitethernet 3/1/1

[RouterB–GigabitEthernet3/1/1] isis enable 1

[RouterB–GigabitEthernet3/1/1] quit

[RouterB] interface gigabitethernet 3/1/2

[RouterB–GigabitEthernet3/1/2] isis enable 1

[RouterB–GigabitEthernet3/1/2] quit

Configuring Router C

# Configure an IP address for GigabitEthernet 3/1/1.

<RouterC> system-view

[RouterC] interface gigabitethernet 3/1/1

[RouterC-GigabitEthernet3/1/1] ip address 192.168.1.2 24

[RouterC-GigabitEthernet3/1/1] quit

# Configure IP addresses for other interfaces, as shown in Figure 1. (Details not shown.)

# Configure IS-IS.

[RouterC] isis 1

[RouterC-isis-1] network-entity 10.1921.6801.0001.00

[RouterC-isis-1] quit

[RouterC] interface gigabitethernet 3/1/1

[RouterC–GigabitEthernet3/1/1] isis enable 1

[RouterC–GigabitEthernet3/1/1] quit

[RouterC] interface gigabitethernet 3/1/2

[RouterC–GigabitEthernet3/1/2] isis enable 1

[RouterC–GigabitEthernet3/1/2] quit

[RouterC] interface gigabitethernet 3/1/3

[RouterC–GigabitEthernet3/1/3] isis enable 1

[RouterC–GigabitEthernet3/1/3] quit

# Configure route leaking from Level-1 to Level-2, and use prefix list 1 to advertise only network 10.100.1.0/24 to Level-2.

[RouterC] ip prefix-list 1 permit 10.100.1.0 24

[RouterC] isis 1

[RouterC-isis-1] address-family ipv4

[RouterC-isis-1-ipv4] import-route isis level-1 into level-2 filter-policy prefix-list 1

[RouterC-isis-1-ipv4] quit

# Enable IS-IS GR.

[RouterC-isis-1] graceful-restart

[RouterC-isis-1] quit

Configuring Router D

# Configure an IP address for GigabitEthernet 3/1/1.

<RouterD> system-view

[RouterD] interface gigabitethernet 3/1/1

[RouterD-GigabitEthernet3/1/1] ip address 192.168.10.2 24

[RouterD-GigabitEthernet3/1/1] quit

# Configure IP addresses for other interfaces, as shown in Figure 1. (Details not shown.)

# Configure IS-IS.

[RouterD] isis 1

[RouterD-isis-1] is-level level-2

[RouterD-isis-1] network-entity 20.1921.6802.0001.00

[RouterD-isis-1] quit

[RouterD] interface gigabitethernet 3/1/1

[RouterD–GigabitEthernet3/1/1] isis enable 1

[RouterD–GigabitEthernet3/1/1] quit

[RouterD] interface gigabitethernet 3/1/2

[RouterD–GigabitEthernet3/1/2] isis enable 1

[RouterD–GigabitEthernet3/1/2] quit

# Configure OSPF.

[RouterD] ospf

[RouterD-ospf-1] area 0

[RouterD-ospf-1-area-0.0.0.0] network 192.168.20.0 0.0.0.255

[RouterD-ospf-1-area-0.0.0.0] quit

[RouterD-ospf-1] quit

# Redistribute OSPF and direct routes into IS-IS

[RouterD] isis 1

[RouterD-isis-1] address-family ipv4

[RouterD-isis-1-ipv4] import-route ospf

[RouterD-isis-1-ipv4] import-route direct

[RouterD-isis-1-ipv4] quit

[RouterD-isis-1] quit

# Redistribute IS-IS and direct routes into OSPF.

[RouterD] ospf 1

[RouterD-ospf-1] import-route isis 1

[RouterD-ospf-1] import-route direct

Configuring Router E

# Configure an IP address for GigabitEthernet 3/1/1.

<RouterE> system-view

[RouterE] interface gigabitethernet 3/1/1

[RouterE-GigabitEthernet3/1/1] ip address 192.168.20.2 24

[RouterE-GigabitEthernet3/1/1] quit

# Configure IP addresses for other interfaces, as shown in Figure 1. (Details not shown.)

# Configure OSPF.

[RouterE] ospf

[RouterE-ospf-1] area 0

[RouterE-ospf-1-area-0.0.0.0] network 192.168.20.0 0.0.0.255

[RouterE-ospf-1-area-0.0.0.0] network 10.200.1.0 0.0.0.255

[RouterE-ospf-1-area-0.0.0.0] quit

[RouterE-ospf-1] quit

Verifying the configuration

# Verify that the branch can reach the Marketing department, but cannot reach the Finance department.

[RouterD] display isis route

                         Route information for IS-IS(1)

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

                         Level-2 IPv4 Forwarding Table

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

 IPv4 Destination     IntCost    ExtCost ExitInterface   NextHop         Flags

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

 192.168.10.0/24      10         NULL    GE3/1/1         Direct          D/L/-

 192.168.1.0/24       20         NULL    GE3/1/1         192.168.10.1    R/-/-

 10.100.1.0/24        30         NULL    GE3/1/1         192.168.10.1    R/-/-

 192.168.2.0/24       20         NULL    GE3/1/1         192.168.10.1    R/-/-

      Flags: D-Direct, R-Added to Rib, L-Advertised in LSPs, U-Up/Down Bit Set

# Verify that the company can communicate with the partner.

·     Display the IS-IS routing table on Router C.

[RouterC] display isis route

 

                         Route information for IS-IS(1)

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

 

                         Level-1 IPv4 Forwarding Table

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

 

 IPv4 Destination     IntCost    ExtCost ExitInterface   NextHop         Flags

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

 192.168.10.0/24      10         NULL    GE3/1/3         Direct          D/L/-

 192.168.1.0/24       10         NULL    GE3/1/1         Direct          D/L/-

 10.100.1.0/24        20         NULL    GE3/1/1         192.168.1.1     R/L/-

 10.100.2.0/24        20         NULL    GE3/1/2         192.168.2.1     R/-/-

 192.168.2.0/24       10         NULL    GE3/1/2         Direct          D/L/-

 

      Flags: D-Direct, R-Added to Rib, L-Advertised in LSPs, U-Up/Down Bit Set

 

                         Level-2 IPv4 Forwarding Table

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

 

 IPv4 Destination     IntCost    ExtCost ExitInterface   NextHop         Flags

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

 192.168.10.0/24      10         NULL    GE3/1/3         Direct          D/L/-

 10.200.1.0/24        10         0       GE3/1/3         192.168.10.2    R/-/-

 192.168.20.0/24      10         0       GE3/1/3         192.168.10.2    R/-/-

 192.168.1.0/24       10         NULL    GE3/1/1         Direct          D/L/-

 192.168.2.0/24       10         NULL    GE3/1/2         Direct          D/L/-

 

      Flags: D-Direct, R-Added to Rib, L-Advertised in LSPs, U-Up/Down Bit Set

·     Ping 10.200.1.1 from the interface VLAN-interface 100 on Router A.

[RouterA] ping –a 10.100.1.1 10.200.1.1

Ping 10.200.1.1 (10.200.1.1): 56 data bytes, press CTRL_C to break

56 bytes from 10.200.1.1: icmp_seq=0 ttl=252 time=1.862 ms

56 bytes from 10.200.1.1: icmp_seq=1 ttl=252 time=2.969 ms

56 bytes from 10.200.1.1: icmp_seq=2 ttl=252 time=1.402 ms

56 bytes from 10.200.1.1: icmp_seq=3 ttl=252 time=1.324 ms

56 bytes from 10.200.1.1: icmp_seq=4 ttl=252 time=1.510 ms

 

--- Ping statistics for 10.200.1.1 ---

5 packet(s) transmitted, 5 packet(s) received, 0.0% packet loss

round-trip min/avg/max/std-dev = 1.324/1.813/2.969/0.606 ms

# Verify that the communication is not interrupted when the IS-IS process restarts.

·     Ping Router B from Router A.

[RouterA] ping -c 10000 10.100.2.1

Ping 10.100.2.1 (10.100.2.1): 56 data bytes, press CTRL_C to break

56 bytes from 10.100.2.1: icmp_seq=0 ttl=254 time=1.185 ms

56 bytes from 10.100.2.1: icmp_seq=1 ttl=254 time=1.087 ms

…

·     Restart the IS-IS process on Router C.

<RouterC> reset isis all graceful-restart

Reset IS-IS process? [Y/N] :y

# Ping Router B from Router A.

[RouterA] ping -c 10000 10.100.2.1

Ping 10.100.2.1 (10.100.2.1): 56 data bytes, press CTRL_C to break

56 bytes from 10.100.2.1: icmp_seq=0 ttl=254 time=1.185 ms

56 bytes from 10.100.2.1: icmp_seq=1 ttl=254 time=1.087 ms

56 bytes from 10.100.2.1: icmp_seq=2 ttl=254 time=1.672 ms

56 bytes from 10.100.2.1: icmp_seq=3 ttl=254 time=1.751 ms

56 bytes from 10.100.2.1: icmp_seq=4 ttl=254 time=1.816 ms

56 bytes from 10.100.2.1: icmp_seq=5 ttl=254 time=1.814 ms

# Check the IS-IS GR state on Router C.

[RouterC] display isis graceful-restart status

                        Restart information for IS-IS(1)

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

Restart status: COMPLETE

Restart phase: Finish

Restart t1: 3, count 10; Restart t2: 60; Restart t3: 300

SA Bit: supported

                          Level-1 restart information

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

Total number of interfaces: 3

Number of waiting LSPs: 0

                          Level-2 restart information

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

Total number of interfaces: 3

Number of waiting LSPs: 0

Configuration files

·     Router A:

#

isis 1

 is-level level-1

 network-entity 10.1921.6800.1001.00

#

interface GigabitEthernet3/1/1

 ip address 192.168.1.1 255.255.255.0

 isis enable 1

#

interface GigabitEthernet3/1/2

 ip address 10.100.1.1 255.255.255.0

 isis enable 1

#

·     Router B:

#

isis 1

 is-level level-1

 network-entity 10.1921.6800.2001.00

#

interface GigabitEthernet3/1/1

 ip address 192.168.2.1 255.255.255.0

 isis enable 1

#

interface GigabitEthernet3/1/2

 ip address 10.100.2.1 255.255.255.0

 isis enable 1

#

·     Router C:

#

isis 1

 graceful-restart

 network-entity 10.1921.6801.0001.00

 #

 address-family ipv4 unicast

  import-route isis level-1 into level-2 filter-policy prefix-list 1

#

interface GigabitEthernet3/1/1

 ip address 192.168.1.2 255.255.255.0

 isis enable 1

#

interface GigabitEthernet3/1/2

 ip address 192.168.2.2 255.255.255.0

 isis enable 1

#

interface GigabitEthernet3/1/3

 ip address 192.168.10.1 255.255.255.0

 isis enable 1

#

 ip prefix-list 1 index 10 permit 10.100.1.0 24

#

·     Router D:

#

isis 1

 is-level level-2

 network-entity 20.1921.6802.0001.00

#

 address-family ipv4 unicast

  import-route direct

  import-route ospf 1

#

ospf 1

 import-route direct

 import-route isis 1

 area 0.0.0.0

  network 192.168.20.0 0.0.0.255

#

interface GigabitEthernet3/1/1

 ip address 192.168.10.2 255.255.255.0

 isis enable 1

#

interface GigabitEthernet3/1/2

 ip address 192.168.20.1 255.255.255.0

#

·     Router E:

#

ospf 1

 area 0.0.0.0

  network 10.200.1.0 0.0.0.255

  network 192.168.20.0 0.0.0.255

#

interface GigabitEthernet3/1/1

 ip address 192.168.20.2 255.255.255.0

#

interface GigabitEthernet3/1/2

 ip address 10.200.1.1 255.255.255.0

#

Related documentation

·     H3C CR16000-F Routers Layer 3—IP Routing Configuration Guide-Release 7951P01

·     H3C CR16000-F Routers Layer 3—IP Routing Command Reference-Release 7951P01