實驗名稱：isis基本配置
實驗拓撲：
[R1]isis ?
INTEGER<1-65535> Process ID
vpn-instance VPN Routing/Forwarding Instance
<cr>
[R1]isis //開啟isis功能，默認開啟進程1
[R1-isis-1]network-entity ?
XX.XXXX. ... .XXXX.XX Network entity title (NET) //網絡實體名稱的格式
[R1-isis-1]network-entity 01.0000.0000.0001.00
[R1-isis-1]is-level ? //三種路由級別配置
level-1 Set the router to operate as a Level-1 (intra-area) router
level-1-2 Set the router to operate as both a Level-1 (intra-area) and
Level-2 (inter-area) router
level-2 Set the router to operate as a Level-2 (inter-area) router
[R1-isis-1]is-level level-1 //配置R1路由級別為level-1
[R1-isis-1]q
[R1]int lo0 //開啟接口isis功能
[R1-LoopBack0]isis ?
circuit-level Set ISIS level for the interface 配置接口level等級
cost Set the interface cost for ISIS 配置isiscost值默認10
enable Enable ISIS processing 開啟接口isis功能
ipv6 Configure IPv6 Commands for ISIS 開啟接口ipv6的isis功能
[R1-LoopBack0]isis enable ?
INTEGER<1-65535> Process ID to attach the interface to
<cr>
[R1-LoopBack0]isis enable 1
[R1]int s0/2/0
[R1-Serial0/2/0]isis enable 1
配置R2的isis
[R2]isis
[R2-isis-1]network-entity 01.0000.0000.0002.00
[R2-isis-1]is-level level-1
[R2]int lo0
[R2-LoopBack0]isis enable 1
[R2-LoopBack0]q
[R2]int s0/2/0
[R2-Serial0/2/0]isis enable
[R2-Serial0/2/0]q
查看命令
查看開啟isis的接口
[R1]display isis interface
Interface information for ISIS(1)
---------------------------------
Interface: LoopBack0
Id IPV4.State IPV6.State MTU Type DIS
001 Up Down 1536 L1/L2 --
Interface: Serial0/2/0
Id IPV4.State IPV6.State MTU Type DIS
002 Up Down 1500 L1/L2 --
上面可以看出，IPv4的端口是開啟的，還有鏈路類型。
有個問題：為什么我們在接口上應用的是leve1而此處顯示的是默認的leve-1-2？
答案：
怎樣變為leve-1呢？請看下面
[R1]int s0/2/0
[R1-Serial0/2/0]isis circuit-level ?
level-1 Establish level-1 adjacency only
level-1-2 Establish level-1-2 adjacency
level-2 Establish level-2 adjacency only
<cr>
[R1-Serial0/2/0]isis circuit-level level-1
[R1-Serial0/2/0]q
[R1]display isis interface
Interface information for ISIS(1)
---------------------------------
Interface: LoopBack0
Id IPV4.State IPV6.State MTU Type DIS
001 Up Down 1536 L1/L2 --
Interface: Serial0/2/0
Id IPV4.State IPV6.State MTU Type DIS
002 Up Down 1500 L1 --
查看路由表信息
[R1]display ip routing-table
Routing Tables: Public
Destinations : 7 Routes : 7
Destination/Mask Proto Pre Cost NextHop Interface
1.1.1.1/32 Direct 0 0 127.0.0.1 InLoop0
2.2.2.2/32 ISIS 15 10 192.168.1.2 S0/2/0
127.0.0.0/8 Direct 0 0 127.0.0.1 InLoop0
127.0.0.1/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.0/24 Direct 0 0 192.168.1.1 S0/2/0
192.168.1.1/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.2/32 Direct 0 0 192.168.1.2 S0/2/0
顯示IS-IS 的IPv4 路由信息。
[R1]display isis route
Route information for ISIS(1)
-----------------------------
ISIS(1) IPv4 Level-1 Forwarding Table
-------------------------------------
IPV4 Destination IntCost ExtCost ExitInterface NextHop Flags
--------------------------------------------------------------------------------
192.168.1.0/24 10 NULL S0/2/0 Direct D/L/-
1.1.1.1/32 0 NULL Loop0 Direct D/L/-
2.2.2.2/32 10 NULL S0/2/0 192.168.1.2 R/-/-
Flags: D-Direct, R-Added to RM, L-Advertised in LSPs, U-Up/Down Bit Set
IPV4 Destination ：IPV4 目的地址
IntCost ：內部路由Cost
ExtCost ：外部路由Cost
ExitInterface ：出接口
NextHop ：下一跳
Flags：
路由狀態標志
D：直連路由
R：該路由是否已放到路由表中
L：是否已經廣播
U：路由滲透狀態標
顯示IS-IS 的鏈路狀態數據庫
[R1]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* 0x0000000c 0xb451 1076 58 0/0/0
0000.0000.0001.00-01* 0x00000008 0x11d0 1076 53 0/0/0
0000.0000.0002.00-00 0x0000001f 0xad3e 1132 58 0/0/0
0000.0000.0002.00-01 0x00000012 0x1bb7 1132 53 0/0/0
*-Self LSP, +-Self LSP(Extended), ATT-Attached, P-Partition, OL-Overload
LSPID 鏈路狀態報文ID
Seq Num LSP 序列號
Checksum LSP 校驗和
Holdtime LSP 保持時間
Length LSP 長度
ATT/P/OL Attach bit（ATT）：連接位；Partition bit（P）：
分區位；Overload bit（OL）：過載位。
顯示IS-IS 當前的基本配置參數
[R1]display isis brief
ISIS (1) Protocol Brief Information :
network-entity:
01.0000.0000.0001.00
is-level :level-1
cost-style: narrow
preference : 15
Lsp-length receive : 1497
Lsp-length originate : level-1 1497
level-2 1497
Timers:
lsp-max-age: 1200
lsp-refresh: 900
Interval between SPFs: 10