1.组网需求
Switch A、Switch B、Switch C和Switch D属于同一自治系统，要求它们之间通过IS-IS协议达到IP网络互连的目的。
Switch A和Switch B为Level-1交换机，Switch D为Level-2交换机，Switch C作为Level-1-2交换机将两个区域相连。Switch A、Switch B和Switch C的区域号为10，Switch D的区域号为20。
2.配置步骤
SW A
[SwitchA] isis 1
[SwitchA-isis-1] is-level level-1
[SwitchA-isis-1] network-entity 10.0000.0000.0001.00
[SwitchA-isis-1] quit
[SwitchA] interface vlan-interface 100
[SwitchA-Vlan-interface100] isis enable 1
SW B
[SwitchB] isis 1
[SwitchB-isis-1] is-level level-1
[SwitchB-isis-1] network-entity 10.0000.0000.0002.00
[SwitchB-isis-1] quit
[SwitchB] interface vlan-interface 200
[SwitchB-Vlan-interface200] isis enable 1
SW D
[SwitchD] isis 1
[SwitchD-isis-1] is-level level-2
[SwitchD-isis-1] network-entity 20.0000.0000.0004.00
[SwitchD-isis-1] quit
[SwitchD] interface vlan-interface 100
[SwitchD-Vlan-interface100] isis enable 1
[SwitchD-Vlan-interface100] quit
[SwitchD] interface vlan-interface 300
[SwitchD-Vlan-interface300] isis enable 1
SW C
[SwitchC] isis 1 [SwitchC-isis-1] network-entity 10.0000.0000.0003.00 [SwitchC-isis-1] quit [SwitchC] interface vlan-interface 100 [SwitchC-Vlan-interface100] isis enable 1 [SwitchC-Vlan-interface100] quit [SwitchC] interface vlan-interface 200 [SwitchC-Vlan-interface200] isis enable 1 [SwitchC-Vlan-interface200] quit [SwitchC] interface vlan-interface 300 [SwitchC-Vlan-interface300] isis enable 1
3.配置验证
1）显示各交换机的IS-IS LSDB信息，查看LSP是否完整。
[SwitchA] display isis lsdb
Database information for IS-IS(1)
---------------------------------
Level-1 Link State Database
---------------------------
LSPID Seq Num Checksum Holdtime Length ATT/P/OL
--------------------------------------------------------------------------
0000.0000.0001.00-00* 0x00000004 0xdf5e 1096 68 0/0/0
0000.0000.0002.00-00 0x00000004 0xee4d 1102 68 0/0/0
0000.0000.0002.01-00 0x00000001 0xdaaf 1102 55 0/0/0
0000.0000.0003.00-00 0x00000009 0xcaa3 1161 111 1/0/0
0000.0000.0003.01-00 0x00000001 0xadda 1112 55 0/0/0
*-Self LSP, +-Self LSP(Extended), ATT-Attached, P-Partition, OL-Overload
[SwitchC] display isis lsdb
Database information for IS-IS(1)
---------------------------------
Level-1 Link State Database
---------------------------
LSPID Seq Num Checksum Holdtime Length ATT/P/OL
--------------------------------------------------------------------------
0000.0000.0001.00-00 0x00000006 0xdb60 847 68 0/0/0
0000.0000.0002.00-00 0x00000008 0xe651 1053 68 0/0/0
0000.0000.0002.01-00 0x00000005 0xd2b3 1052 55 0/0/0
0000.0000.0003.00-00* 0x00000014 0x194a 1051 111 1/0/0
0000.0000.0003.01-00* 0x00000002 0xabdb 854 55 0/0/0
*-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* 0x00000012 0xc93c 842 100 0/0/0
0000.0000.0004.00-00 0x00000026 0x331 1173 84 0/0/0
0000.0000.0004.01-00 0x00000001 0xee95 668 55 0/0/0
*-Self LSP, +-Self LSP(Extended), ATT-Attached, P-Partition, OL-Overload
2）显示各交换机的IS-IS路由信息。Level-1交换机的路由表中应该有一条缺省路由，且下一跳为Level-1-2交换机，Level-2交换机的路由表中应该有所有Level-1和Level-2的路由。
[SwitchA] display isis route
Route information for IS-IS(1)
------------------------------
Level-1 IPv4 Forwarding Table
-----------------------------
IPv4 Destination IntCost ExtCost ExitInterface NextHop Flags
-------------------------------------------------------------------------------
10.1.1.0/24 10 NULL Vlan100 Direct D/L/-
10.1.2.0/24 20 NULL Vlan100 10.1.1.1 R/-/-
192.168.0.0/24 20 NULL Vlan100 10.1.1.1 R/-/-
0.0.0.0/0 10 NULL Vlan100 10.1.1.1 R/-/-
Flags: D-Direct, R-Added to Rib, L-Advertised in LSPs, U-Up/Down Bit Set
[SwitchC] display isis route Route information for IS-IS(1) ------------------------------ Level-1 IPv4 Forwarding Table ----------------------------- IPv4 Destination IntCost ExtCost ExitInterface NextHop Flags ------------------------------------------------------------------------------- 192.168.0.0/24 10 NULL Vlan300 Direct D/L/- 10.1.1.0/24 10 NULL Vlan100 Direct D/L/- 10.1.2.0/24 10 NULL Vlan200 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 ------------------------------------------------------------------------------- 192.168.0.0/24 10 NULL D/L/- 10.1.1.0/24 10 NULL D/L/- 10.1.2.0/24 10 NULL D/L/- 172.16.0.0/16 20 NULL Vlan300 192.168.0.2 R/-/- Flags: D-Direct, R-Added to Rib, L-Advertised in LSPs, U-Up/Down Bit Set
[SwitchD] display isis route Route information for IS-IS(1) ------------------------------ Level-2 IPv4 Forwarding Table ----------------------------- IPv4 Destination IntCost ExtCost ExitInterface NextHop Flags ------------------------------------------------------------------------------- 192.168.0.0/24 10 NULL Vlan300 Direct D/L/- 10.1.1.0/24 20 NULL Vlan300 192.168.0.1 R/-/- 10.1.2.0/24 20 NULL Vlan300 192.168.0.1 R/-/- 172.16.0.0/16 10 NULL Vlan100 Direct D/L/-