H3C S6890 Switch Series
IS-IS Route Summarization
Configuration Examples

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Document version: 6W100-20190628

 

Contents

Introduction· 1

Prerequisites· 1

Example: Configuring IS-IS route summarization· 1

Network configuration· 1

Analysis· 2

Software versions used· 2

Restrictions and guidelines· 3

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

Related documentation· 6

 

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.

Software versions used

This configuration example was created and verified on S6890-CMW710-R2712.

Restrictions and guidelines

By default, interfaces on the device are disabled (in ADM or Administratively Down state). To have an interface operate, you must use the undo shutdown command to enable that interface.

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.)

Related documentation

·          H3C S6890 Switch Series Layer 3—IP Routing Command Reference (R27xx)

·          H3C S6890 Switch Series Layer 3—IP Routing Configuration Guide (R27xx)