Example for Configuring Basic IS-IS Functions

This section describes how to configure basic IS-IS functions, including specifying the NET, configuring the IS-IS level, and enabling IS-IS on each device.

Networking Requirements

In Figure 1:

  • Device A, Device B, Device C, and Device D run IS-IS for IP interworking.

  • Device A, Device B, and Device C belong to Area 10, and Device D belongs to Area 20.

  • Device A and Device B are Level-1 devices; Device C is a Level-1-2 device; Device D is a Level-2 device.

Figure 1 Configuring basic IS-IS functions

Device Name

Interface

IP Address

Device A

GE0/1/0

10.1.1.2/24

Device B

GE0/1/0

10.1.2.2/24

Device C

GE0/1/0

10.1.1.1/24

GE0/1/8

10.1.2.1/24

GE0/1/16

192.168.0.1/24

Device D

GE0/1/0

192.168.0.2/24

GE0/1/8

172.16.1.1/16

Configuration Roadmap

The configuration roadmap is as follows:

  1. Enable IS-IS, configure the level, and specify the NET on each router.

  2. Configure Device A and Device C to authenticate Hello packets in a specified mode and with the specified password.

  3. View the IS-IS LSDB and the routing table of each router.

Data Preparation

To complete the configuration, you need the following data:

  • Area addresses of Device A, Device B, Device C, and Device D

  • Levels of Device A, Device B, Device C, and Device D

Procedure

  1. Configure an IP address for each interface.

    This example assumes that you know the configuration method and no details are provided here, for detailed configurations, see Figure 1 and configuration files in this example.

  2. Configure basic IS-IS functions.

    # Configure Device A.

    [~DeviceA] isis 1
[*DeviceA-isis-1] is-level level-1
[*DeviceA-isis-1] network-entity 10.0000.0000.0001.00
[*DeviceA-isis-1] quit
[*DeviceA] interface gigabitethernet 0/1/0
[*DeviceA-GigabitEthernet0/1/0] isis enable 1
[*DeviceA-GigabitEthernet0/1/0] isis circuit-type p2p
[*DeviceA-GigabitEthernet0/1/0] commit
[~DeviceA-GigabitEthernet0/1/0] quit

    # Configure Device B.

    [~DeviceB] isis 1
[*DeviceB-isis-1] is-level level-1
[*DeviceB-isis-1] network-entity 10.0000.0000.0002.00
[*DeviceB-isis-1] quit
[*DeviceB] interface gigabitethernet 0/1/0
[*DeviceB-GigabitEthernet0/1/0] isis enable 1
[*DeviceB-GigabitEthernet0/1/0] isis circuit-type p2p
[*DeviceA-GigabitEthernet0/1/0] commit
[~DeviceB-GigabitEthernet0/1/0] quit

    # Configure Device C.

    [~DeviceC] isis 1
[*DeviceC-isis-1] is-level level-1-2
[*DeviceC-isis-1] network-entity 10.0000.0000.0003.00
[*DeviceC-isis-1] quit
[*DeviceC] interface gigabitethernet 0/1/0
[*DeviceC-GigabitEthernet0/1/0] isis enable 1
[*DeviceC-GigabitEthernet0/1/0] isis circuit-type p2p
[*DeviceC-GigabitEthernet0/1/0] quit
[*DeviceC] interface gigabitethernet 0/1/8
[*DeviceC-GigabitEthernet0/1/8] isis enable 1
[*DeviceC-GigabitEthernet0/1/8] isis circuit-type p2p
[*DeviceC-GigabitEthernet0/1/8] quit
[*DeviceC] interface gigabitethernet 0/1/16
[*DeviceC-GigabitEthernet0/1/16] isis enable 1
[*DeviceC-GigabitEthernet0/1/16] isis circuit-type p2p
[*DeviceC-GigabitEthernet0/1/16] commit
[~DeviceC-GigabitEthernet0/1/16] quit

    # Configure Device D.

    [~DeviceD] isis 1
[*DeviceD-isis-1] is-level level-2
[*DeviceD-isis-1] network-entity 20.0000.0000.0004.00
[*DeviceD-isis-1] quit
[*DeviceD] interface gigabitethernet 0/1/8
[*DeviceD-GigabitEthernet0/1/8] isis enable 1
[*DeviceD-GigabitEthernet0/1/8] isis circuit-type p2p
[*DeviceD-GigabitEthernet0/1/8] quit
[*DeviceD] interface gigabitethernet 0/1/0
[*DeviceD-GigabitEthernet0/1/0] isis enable 1
[*DeviceD-GigabitEthernet0/1/0] isis circuit-type p2p
[*DeviceD-GigabitEthernet0/1/0] commit
[~DeviceD-GigabitEthernet0/1/0] quit

  3. Configure the authentication mode and password used by Device A and Device C to authenticate Hello packets.

    # Configure Device A.

    [~DeviceA] interface gigabitethernet 0/1/0
[~DeviceA-GigabitEthernet0/1/0] isis authentication-mode simple cipher N`C55QK<`=/Q=^Q`MAF4<1!!
[*DeviceA-GigabitEthernet0/1/0] commit
[~DeviceA-GigabitEthernet0/1/0] quit

    # Configure Device C.

    [~DeviceC] interface gigabitethernet 0/1/0
[~DeviceC-GigabitEthernet0/1/0] isis authentication-mode simple cipher N`C55QK<`=/Q=^Q`MAF4<1!!
[*DeviceC-GigabitEthernet0/1/0] commit
[~DeviceC-GigabitEthernet0/1/0] quit

  4. Verify the configuration.

    # Display the IS-IS LSDB of each router.

    [~DeviceA] display isis lsdb
Database information for ISIS(1)
--------------------------------
Level-1 Link State Database
LSPID                 Seq Num      Checksum      Holdtime      Length  ATT/P/OL
-------------------------------------------------------------------------------
0000.0000.0001.00-00* 0x00000006   0xbf7d        649           68      0/0/0
0000.0000.0002.00-00  0x00000003   0xef4d        545           68      0/0/0
0000.0000.0003.00-00  0x00000008   0x3340        582           111     0/1/0
Total LSP(s): 3
*(In TLV)-Leaking Route, *(By LSPID)-Self LSP, +-Self LSP(Extended),
ATT-Attached, P-Partition, OL-Overload 
[~DeviceB] display isis lsdb
Database information for ISIS(1)
--------------------------------
Level-1 Link State Database
LSPID                 Seq Num      Checksum      Holdtime      Length  ATT/P/OL
-------------------------------------------------------------------------------
0000.0000.0001.00-00  0x00000006   0xbf7d        642           68      0/0/0
0000.0000.0002.00-00* 0x00000003   0xef4d        538           68      0/0/0
0000.0000.0003.00-00  0x00000008   0x3340        574           111     0/1/0
Total LSP(s): 3 
*(In TLV)-Leaking Route, *(By LSPID)-Self LSP, +-Self LSP(Extended),
ATT-Attached, P-Partition, OL-Overload
[~DeviceC] display isis lsdb
Database information for ISIS(1)
--------------------------------
Level-1 Link State Database
LSPID                 Seq Num      Checksum      Holdtime      Length  ATT/P/OL
-------------------------------------------------------------------------------
0000.0000.0001.00-00  0x00000006   0xbf7d        638           68      0/0/0
0000.0000.0002.00-00  0x00000003   0xef4d        533           68      0/0/0
0000.0000.0003.00-00* 0x00000008   0x3340        569           111     0/1/0
Total LSP(s): 3
*(In TLV)-Leaking Route, *(By LSPID)-Self LSP, +-Self LSP(Extended),
ATT-Attached, P-Partition, OL-Overload
Level-2 Link State Database
LSPID                 Seq Num      Checksum      Holdtime      Length  ATT/P/OL
-------------------------------------------------------------------------------
0000.0000.0003.00-00* 0x00000008   0x55bb        650           100     0/0/0
0000.0000.0004.00-00  0x00000005   0x651         629           84      0/0/0
Total LSP(s): 2
*(In TLV)-Leaking Route, *(By LSPID)-Self LSP, +-Self LSP(Extended),
ATT-Attached, P-Partition, OL-Overload
[~DeviceD] display isis lsdb
Database information for ISIS(1)
--------------------------------
Level-2 Link State Database
LSPID                 Seq Num      Checksum      Holdtime      Length  ATT/P/OL
-------------------------------------------------------------------------------
0000.0000.0003.00-00  0x00000008   0x55bb        644           100     0/0/0
0000.0000.0004.00-00* 0x00000005   0x651         624           84      0/0/0
Total LSP(s): 2
*(In TLV)-Leaking Route, *(By LSPID)-Self LSP, +-Self LSP(Extended),
ATT-Attached, P-Partition, OL-Overload

    # Display the IS-IS routing table of each router. In the routing table of a Level-1 device, there must be a default route with a Level-1-2 device as the next hop. The routing table of a Level-2 device must have all Level-1 and Level-2 routes.

    [~DeviceA] display isis route
Route information for ISIS(1)
-----------------------------
ISIS(1) Level-1 Forwarding Table
--------------------------------
IPV4 Destination   IntCost   ExtCost ExitInterface   NextHop         Flags
-------------------------------------------------------------------------
10.1.1.0/24        10        NULL    GE0/1/0         Direct          D/-/L/-/-
10.1.2.0/24        20        NULL    GE0/1/0         10.1.1.1        A/-/-/-/-
192.168.0.0/24     20        NULL    GE0/1/0         10.1.1.1        A/-/-/-/-
0.0.0.0/0          10        NULL    GE0/1/0         10.1.1.1        A/-/-/-/-
 Flags: D-Direct, A-Added to URT, L-Advertised in LSPs, S-IGP Shortcut,
                                 U-Up/Down Bit Set
    Protect Type: L-Link Protect, N-Node Protect
[~DeviceC] display isis route
                         Route information for ISIS(1)
                         -----------------------------
                        ISIS(1) Level-1 Forwarding Table
                        --------------------------------
IPV4 Destination   IntCost   ExtCost ExitInterface   NextHop         Flags
-------------------------------------------------------------------------
 10.1.1.0/24        10        NULL    GE0/1/0         Direct          D/-/L/-/-
 10.1.2.0/24        10        NULL    GE0/1/8         Direct          D/-/L/-/-
 192.168.0.0/24     10        NULL    GE0/1/16         Direct          D/-/L/-/-
    Flags: D-Direct, A-Added to URT, L-Advertised in LSPs, S-IGP Shortcut,
                                U-Up/Down Bit Set
    Protect Type: L-Link Protect, N-Node Protect
                        ISIS(1) Level-2 Forwarding Table
                        --------------------------------
 IPV4 Destination   IntCost   ExtCost ExitInterface   NextHop         Flags
-------------------------------------------------------------------------
 10.1.1.0/24        10        NULL    -               Direct          D/-/L/-/-
 10.1.2.0/24        10        NULL    -               Direct          D/-/L/-/-
 192.168.0.0/24     10        NULL    -               Direct          D/-/L/-/-
 172.16.0.0/16      20        NULL    GE0/1/16         192.168.0.2     A/-/-/-/-
    Flags: D-Direct, A-Added to URT, L-Advertised in LSPs, S-IGP Shortcut,
                                 U-Up/Down Bit Set
    Protect Type: L-Link Protect, N-Node Protect
[~DeviceD] display isis route
                         Route information for ISIS(1)
                         -----------------------------
                        ISIS(1) Level-2 Forwarding Table
                        --------------------------------
 IPV4 Destination   IntCost   ExtCost ExitInterface   NextHop          Flags
--------------------------------------------------------------------------
 192.168.0.0/24     10        NULL    GE0/1/16         Direct           D/-/L/-/-
 10.1.1.0/24        20        NULL    GE0/1/16         192.168.0.1      A/-/-/-/-
 10.1.2.0/24        20        NULL    GE0/1/16         192.168.0.1      A/-/-/-/-
 172.16.0.0/16      10        NULL    GE0/1/8         Direct           D/-/L/-/-
    Flags: D-Direct, A-Added to URT, L-Advertised in LSPs, S-IGP Shortcut,
                                 U-Up/Down Bit Set
    Protect Type: L-Link Protect, N-Node Protect

Configuration Files

  • Device A configuration file

    #
sysname DeviceA
#
isis 1
 is-level level-1
 network-entity 10.0000.0000.0001.00
#
interface GigabitEthernet0/1/0
 undo shutdown
ip address 10.1.1.2 255.255.255.0
 isis enable 1
 isis circuit-type p2p
 isis authentication-mode simple cipher N`C55QK<`=/Q=^Q`MAF4<1!!
#
return

  • Device B configuration file

    #
sysname DeviceB
#
isis 1
 is-level level-1
network-entity 10.0000.0000.0002.00
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 10.1.2.2 255.255.255.0
 isis enable 1
 isis circuit-type p2p
#
return

  • Device C configuration file

    #
sysname DeviceC
#
isis 1
 is-level level-1-2
 network-entity 10.0000.0000.0003.00
#
interface GigabitEthernet0/1/0
undo shutdown
ip address 10.1.1.1 255.255.255.0
 isis enable 1
 isis circuit-type p2p
 isis authentication-mode simple cipher N`C55QK<`=/Q=^Q`MAF4<1!!
#
interface GigabitEthernet0/1/8
 undo shutdown
 ip address 10.1.2.1 255.255.255.0
 isis enable 1
 isis circuit-type p2p
#
interface GigabitEthernet0/1/16
 undo shutdown
 ip address 192.168.0.1 255.255.255.0
 isis enable 1
 isis circuit-type p2p
#
return

  • Device D configuration file

    #
sysname DeviceD
#
isis 1
 is-level level-2
 network-entity 20.0000.0000.0004.00
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 192.168.0.2 255.255.255.0
isis enable 1
 isis circuit-type p2p
#
interface GigabitEthernet0/1/8
 undo shutdown
 ip address 172.16.1.1 255.255.0.0
 isis enable 1
 isis circuit-type p2p
#
return
Parent Topic: IS-IS Configuration Examples
Copyright © Huawei Technologies Co., Ltd.
Copyright © Huawei Technologies Co., Ltd.
Next topic >