Contents

Introduction· 1

Prerequisites· 1

Example: Configuring IS-IS route summarization· 1

Network configuration· 1

Analysis· 2

Applicable hardware and software versions· 2

Procedures· 3

Configuring IP addresses for interfaces· 3

Configuring basic IS-IS· 3

Configuring IS-IS route summarization· 4

Verifying the configuration· 4

Configuration files· 5

 

Introduction

This document provides IS-IS route summarization 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 route summarization.

Example: Configuring IS-IS route summarization

Network configuration

As shown in Figure 1, the five departments of a company use IS-IS to connect to the backbone network. The five departments are assigned the networks 192.168.1.0/24, 192.168.2.0/24, 192.168.3.0/24, 192.168.4.0/24, and 192.168.5.0/24. Configure IS-IS route summarization to reduce routing entries and save system resources for Device B.

Figure 1 Network diagram

 

Table 1 Interface and IP address assignment

Device	Interface	IP address	Device	Interface	IP address
Device A	Vlan-int10	172.16.1.1/24	Device B	Vlan-int10	172.168.1.2/24
	Vlan-int101	10.1.1.1/24	GW 1	Vlan-int101	10.1.1.2/24
	Vlan-int102	10.1.2.1/24	GW 2	Vlan-int102	10.1.2.2/24
	Vlan-int103	10.1.3.1/24	GW3	Vlan-int103	10.1.3.2/24

 

Analysis

Configure route summarization on Device A because route summarization applies only to locally generated LSPs.

To avoid blackhole routes, set the summary route to 192.168.0.0/22.

Applicable hardware and software versions

The following matrix shows the hardware and software versions to which this configuration example is applicable:

 

Hardware	Software version
S6520X-HI switch series S6520X-EI switch series	Supported in Release 1110P01
S6520X-SI switch series S6520-SI switch series S5000-EI switch series MS4600 switch series	Supported in Release 1110P01

 

Procedures

Configuring IP addresses for interfaces

# Configure an IP address for the interface VLAN-interface 10 on Device A.

<DeviceA> system-view

[DeviceA] interface vlan-interface 10

[DeviceA-Vlan-interface10] ip address 172.16.1.1 24

[DeviceA-Vlan-interface10] quit

# Configure IP addresses for other interfaces as shown in Figure 1 in the same way VLAN-interface 10 is configured. (Details not shown.)

Configuring basic IS-IS

Configuring Device A

# Enable IS-IS on Device A and configure Device A as a Level-1-2 router.

[DeviceA] isis 1

[DeviceA-isis-1] network-entity 10.0000.0000.0001.00

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

[DeviceA-isis-1] quit

# Enable IS-IS on the interface VLAN-interface 10.

[DeviceA] interface vlan-interface 10

[DeviceA–Vlan-interface10] isis enable 1

[DeviceA–Vlan-interface10] quit

# Configure other interfaces in the same way VLAN-interface 10 is configured. (Details not shown.)

Configuring Device B

# Enable IS-IS on Device B and configure Device B as a Level-2 router.

[DeviceB] isis 1

[DeviceB-isis-1] network-entity 10.0000.0000.0002.00

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

[DeviceB-isis-1] quit

# Enable IS-IS on the interface VLAN-interface 10.

[DeviceB] interface vlan-interface 10

[DeviceB–Vlan-interface10] isis enable 1

[DeviceB–Vlan-interface10] quit

Configuring the gateways

# Enable IS-IS on GW 1 and configure GW 1 as a Level-1 router.

[GW1] isis 1

[GW1-isis-1] network-entity 10.0001.0001.0001.00

[GW1-isis-1] is-level level-1

[GW1-isis-1] quit

# Enable IS-IS on the interface VLAN-interface 11.

[GW1] interface vlan-interface 11

[GW1–Vlan-interface11] isis enable 1

[GW1–Vlan-interface11] quit

# Configure other gateways in the same way GW 1 is configured. (Details not shown.)

Displaying IS-IS routing information on Device B

# Display IS-IS routing information on Device B to view the network address of each department.

[DeviceB] display isis route

 

Route information for IS-IS(1)

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

 

                         Level-2 IPv4 Forwarding Table

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

 

 IPv4 Destination     IntCost    ExtCost ExitInterface   NextHop         Flags

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

 192.168.1.0/24       30         NULL    Vlan10          172.16.1.1      R/-/-

 10.1.1.0/24          20         NULL    Vlan10          172.16.1.1      R/-/-

 192.168.2.0/24       30         NULL    Vlan10          172.16.1.1      R/-/-

 10.1.2.0/24          20         NULL    Vlan10          172.16.1.1      R/-/-

 192.168.3.0/24       30         NULL    Vlan10          172.16.1.1      R/-/-

 10.1.3.0/24          20         NULL    Vlan10          172.16.1.1      R/-/-

 172.16.1.0/24        10         NULL    Vlan10          Direct          D/L/-

 

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

Configuring IS-IS route summarization

# Configure IS-IS route summarization on Device A.

[DeviceA] isis 1

[DeviceA] address-family ipv4

[DeviceA-isis-1-ipv4]summary 192.168.0.0 22

Verifying the configuration

# Display IS-IS routing information on Device B.

[DeviceB] display isis route

 

                         Route information for IS-IS(1)

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

 

                         Level-2 IPv4 Forwarding Table

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

 

 IPv4 Destination     IntCost    ExtCost ExitInterface   NextHop         Flags

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

 10.1.1.0/24          20         NULL    Vlan10          172.16.1.1      R/-/-

 10.1.2.0/24          20         NULL    Vlan10          172.16.1.1      R/-/-

 10.1.3.0/24          20         NULL    Vlan10          172.16.1.1      R/-/-

 172.16.1.0/24        10         NULL    Vlan10          Direct          D/L/-

 192.168.0.0/22       30         NULL    Vlan10          172.16.1.1      R/-/-

 

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

The output shows that the networks have been summarized into a single network 192.168.0.0/22.

Configuration files

·     Device A:

#

isis 1

 network-entity 10.0000.0000.0001.00

 #

 address-family ipv4 unicast

  summary 192.168.0.0 255.255.252.0

#

vlan 10

#

vlan 101 to 103

#

interface vlan-interface10

 ip address 172.16.1.1 255.255.255.0

 isis enable 1

#

interface vlan-interface101

 ip address 10.1.1.1 255.255.255.0

 isis enable 1

#

interface vlan-interface102

 ip address 10.1.2.1 255.255.255.0

 isis enable 1

#

interface vlan-interface103

 ip address 10.1.3.1 255.255.255.0

 isis enable 1

#

·     Device B:

#

isis 1

 is-level level-2

 network-entity 10.0000.0000.0002.00

#

vlan 10

#

interface vlan-interface10

 ip address 172.16.1.2 255.255.255.0

 isis enable 1

#

·     GW 1:

#

isis 1

 is-level level-1

 network-entity 10.0001.0001.0001.00

#

vlan 11

#

vlan 101

#

interface vlan-interface101

 ip address 10.1.1.2 255.255.255.0

 isis enable 1

#

interface vlan-interface11

 ip address 192.168.1.1 255.255.255.0

 isis enable 1

#

·     The configuration files for other gateways are similar to the configuration file for GW 1. (Details not shown.)