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

Router A· 7

Router B· 8

Router C· 8

Router D·· 8

Router E· 9

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

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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 Ten-GigabitEthernet 0/0/15.

<RouterA> system-view

[RouterA] interface ten-gigabitethernet 0/0/15

[RouterA-Ten-GigabitEthernet0/0/15] ip address 192.168.1.1 24

[RouterA-Ten-GigabitEthernet0/0/15] 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 ten-gigabitethernet 0/0/15

[RouterA–Ten-GigabitEthernet0/0/15] isis enable 1

[RouterA–Ten-GigabitEthernet0/0/15] quit

[RouterA] interface ten-gigabitethernet 0/0/16

[RouterA–Ten-GigabitEthernet0/0/16] isis enable 1

[RouterA–Ten-GigabitEthernet0/0/16] quit

Configuring Router B

# Configure an IP address for Ten-GigabitEthernet 0/0/15.

<RouterB> system-view

[RouterB] interface ten-gigabitethernet 0/0/15

[RouterB-Ten-GigabitEthernet0/0/15] ip address 192.168.2.1 24

[RouterB-Ten-GigabitEthernet0/0/15] 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 ten-gigabitethernet 0/0/15

[RouterB–Ten-GigabitEthernet0/0/15] isis enable 1

[RouterB–Ten-GigabitEthernet0/0/15] quit

[RouterB] interface ten-gigabitethernet 0/0/16

[RouterB–Ten-GigabitEthernet0/0/16] isis enable 1

[RouterB–Ten-GigabitEthernet0/0/16] quit

Configuring Router C

# Configure an IP address for Ten-GigabitEthernet 0/0/15.

<RouterC> system-view

[RouterC] interface ten-gigabitethernet 0/0/15

[RouterC-Ten-GigabitEthernet0/0/15] ip address 192.168.1.2 24

[RouterC-Ten-GigabitEthernet0/0/15] 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 ten-gigabitethernet 0/0/15

[RouterC–Ten-GigabitEthernet0/0/15] isis enable 1

[RouterC–Ten-GigabitEthernet0/0/15] quit

[RouterC] interface ten-gigabitethernet 0/0/16

[RouterC–Ten-GigabitEthernet0/0/16] isis enable 1

[RouterC–Ten-GigabitEthernet0/0/16] quit

[RouterC] interface ten-gigabitethernet 0/0/17

[RouterC–Ten-GigabitEthernet0/0/17] isis enable 1

[RouterC–Ten-GigabitEthernet0/0/17] 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 Ten-GigabitEthernet 0/0/15.

<RouterD> system-view

[RouterD] interface ten-gigabitethernet 0/0/15

[RouterD-Ten-GigabitEthernet0/0/15] ip address 192.168.10.2 24

[RouterD-Ten-GigabitEthernet0/0/15] 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 ten-gigabitethernet 0/0/15

[RouterD–Ten-GigabitEthernet0/0/15] isis enable 1

[RouterD–Ten-GigabitEthernet0/0/15] quit

[RouterD] interface ten-gigabitethernet 0/0/16

[RouterD–Ten-GigabitEthernet0/0/16] isis enable 1

[RouterD–Ten-GigabitEthernet0/0/16] 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 Ten-GigabitEthernet 0/0/15.

<RouterE> system-view

[RouterE] interface ten-gigabitethernet 0/0/15

[RouterE-Ten-GigabitEthernet0/0/15] ip address 192.168.20.2 24

[RouterE-Ten-GigabitEthernet0/0/15] 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    XGE0/0/15        Direct          D/L/-

 192.168.1.0/24       20         NULL    XGE0/0/15        192.168.10.1    R/-/-

 10.100.1.0/24        30         NULL    XGE0/0/15        192.168.10.1    R/-/-

 192.168.2.0/24       20         NULL    XGE0/0/15        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    XGE0/0/17        Direct          D/L/-

 192.168.1.0/24       10         NULL    XGE0/0/15        Direct          D/L/-

 10.100.1.0/24        20         NULL    XGE0/0/15        192.168.1.1     R/L/-

 10.100.2.0/24        20         NULL    XGE0/0/16        192.168.2.1     R/-/-

 192.168.2.0/24       10         NULL    XGE0/0/16        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    XGE0/0/17        Direct          D/L/-

 10.200.1.0/24        10         0       XGE0/0/17        192.168.10.2    R/-/-

 192.168.20.0/24      10         0       XGE0/0/17        192.168.10.2    R/-/-

 192.168.1.0/24       10         NULL    XGE0/0/15        Direct          D/L/-

 192.168.2.0/24       10         NULL    XGE0/0/16        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 XGE3/1/23/0/2 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 ten-gigabitethernet 0/0/15

 ip address 192.168.1.1 255.255.255.0

 isis enable 1

#

interface ten-gigabitethernet 0/0/16

 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 ten-gigabitethernet 0/0/15

 ip address 192.168.2.1 255.255.255.0

 isis enable 1

#

interface ten-gigabitethernet 0/0/16

 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 ten-gigabitethernet 0/0/15

 ip address 192.168.1.2 255.255.255.0

 isis enable 1

#

interface ten-gigabitethernet 0/0/16

 ip address 192.168.2.2 255.255.255.0

 isis enable 1

#

interface ten-gigabitethernet 0/0/17

 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 ten-gigabitethernet 0/0/15

 ip address 192.168.10.2 255.255.255.0

 isis enable 1

#

interface ten-gigabitethernet 0/0/16

 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 ten-gigabitethernet 0/0/15

 ip address 192.168.20.2 255.255.255.0

#

interface ten-gigabitethernet 0/0/17

 ip address 10.200.1.1 255.255.255.0

#

Related documentation

·     H3C CR16000-M1A Routers Layer—3 IP Routing Configuration Guide

·     H3C CR16000-M1A Routers Layer—3 IP Routing Command Reference