组网需求
- 网络中有三台路由器通过IS-IS协议实现互联互通
- Router A与Router B之间通过二层交换实现互联
- 要求当Router A与Router B之间路由器故障能够对故障结果做出反应,重新建立邻居
网络拓扑
配置思路
- 配置路由器基本功能以及IP地址
- 配置IS-IS协议以及接口使能IS-IS协议
- 配置静态BFD
- 配置IS-IS协议与BFD联动
配置命令
配置路由器基本功能以及IP地址
Router A配置
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4sys
sys Router A
int g0/0/0
ip add 100.1.1.1 30
Router B配置
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6sys
sys Router B
int g0/0/0
ip add 100.1.1.2 30
int g0/0/1
ip add 100.2.1.1 30
Router C配置
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sys Router C
int g0/0/1
ip add 100.2.1.2 30
配置IS-IS协议以及接口使能IS-IS协议
Router A配置
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7sys
isis 1
is-level level-2
network-entity 86.0010.1000.0100.1001.00
int g0/0/0
isis enable 1
isis small-hello
Router B配置
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10sys
isis 1
is-level level-2
network-entity 86.0010.1000.0100.1002.00
int g0/0/0
isis enable 1
isis small-hello
int g0/0/1
isis enable 1
isis small-hello
Router C配置
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7sys
isis 1
is-level level-2
network-entity 86.0010.1000.0200.1002.00
int g0/0/1
isis enable 1
isis small-hello
配置静态BFD
Router A配置
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8sys
bfd
q
bfd A-to-B bind peer-ip 100.1.1.2 int g0/0/0
discriminator local 1
discriminator remote 2
commit
q
Router B配置
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8sys
bfd
q
bfd B-to-A bind peer-ip 100.1.1.1 int g0/0/0
discriminator local 2
discriminator remote 1
commit
q
配置IS-IS接口使能BFD
Router A配置
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3sys
int g0/0/0
isis bfd static
Router B配置
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3sys
int g0/0/0
isis bfd static
测试结果
查看命令
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40查看IS-IS邻居
dis isis peer
<Router A>dis isis peer
Peer information for ISIS(1)
System Id Interface Circuit Id State HoldTime Type PRI
-------------------------------------------------------------------------------
1000.0100.1002 GE0/0/0 1000.0100.1001.01 Up 20s L2 64
Total Peer(s): 1
查看IS-IS路由
dis isis route
<Router A>dis isis route
Route information for ISIS(1)
-----------------------------
ISIS(1) Level-2 Forwarding Table
--------------------------------
IPV4 Destination IntCost ExtCost ExitInterface NextHop Flags
-------------------------------------------------------------------------------
100.1.1.0/30 10 NULL GE0/0/0 Direct D/-/L/-
100.2.1.0/30 20 NULL GE0/0/0 100.1.1.2 A/-/-/-
Flags: D-Direct, A-Added to URT, L-Advertised in LSPs, S-IGP Shortcut,
U-Up/Down Bit Set
查看BFD会话状态
dis bfd session all
<Router A>dis bfd session all
--------------------------------------------------------------------------------
Local Remote PeerIpAddr State Type InterfaceName
--------------------------------------------------------------------------------
1 2 100.1.1.2 Up S_IP_IF GigabitEthernet0/0/0
--------------------------------------------------------------------------------
Total UP/DOWN Session Number : 1/0
打开终端日志信息功能
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3terminal logging
terminal monitor
测试
Router B端口down掉
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3sys
int g0/0/0
shutdown
Router A日志信息和BFD状态以及IS-IS邻居状态
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49日志信息
<Router A>
Mar 2 2022 11:25:10-08:00 Router A %%01BFD/4/STACHG_TODWN(l)[0]:BFD session cha
nged to Down. (SlotNumber=0, Discriminator=16777216, Diagnostic=DetectDown, Appl
ications=None, ProcessPST=False, BindInterfaceName=GigabitEthernet0/0/0, Interfa
cePhysicalState=Up, InterfaceProtocolState=Up)
<Router A>
Mar 2 2022 11:25:10-08:00 Router A %%01ISIS/4/PEER_DOWN_BFDDOWN(l)[1]:ISIS 256
neighbor 1000.0100.1002 was Down on interface GE0/0/0 because the BFD node was d
own. The Hello packet was received at 11:18:26 last time; the maximum interval f
or sending Hello packets was 270991360; the local router sent 4127719424 Hello p
ackets and received 83886080 packets; the type of the Hello packet was Lan Level
-2.
<Router A>
Mar 2 2022 11:25:10-08:00 Router A %%01ISIS/4/ADJ_CHANGE_LEVEL(l)[2]:The neighb
or of ISIS was changed. (IsisProcessId=256, Neighbor=1000.0100.1002, InterfaceNa
me=GE0/0/0, CurrentState=up, ChangeType=L2_BFD_DOWN, Level=Level-2)
<Router A>
Mar 2 2022 11:25:10-08:00 Router A %%01ISIS/4/ADJ_CHANGE_LEVEL(l)[3]:The neighb
or of ISIS was changed. (IsisProcessId=256, Neighbor=1000.0100.1002, InterfaceNa
me=GE0/0/0, CurrentState=down, ChangeType=L2_HOLDTIMER_EXPIRED, Level=Level-2)
BFD会话状态
<Router A>dis bfd session all
--------------------------------------------------------------------------------
Local Remote PeerIpAddr State Type InterfaceName
--------------------------------------------------------------------------------
1 2 100.1.1.2 Down S_IP_IF GigabitEthernet0/0/0
--------------------------------------------------------------------------------
Total UP/DOWN Session Number : 0/1
IS-IS邻居
dis isis peer
dis isis route
<Router A>dis isis route
Route information for ISIS(1)
-----------------------------
ISIS(1) Level-2 Forwarding Table
--------------------------------
IPV4 Destination IntCost ExtCost ExitInterface NextHop Flags
-------------------------------------------------------------------------------
100.1.1.0/30 10 NULL GE0/0/0 Direct D/-/L/-
Flags: D-Direct, A-Added to URT, L-Advertised in LSPs, S-IGP Shortcut,
U-Up/Down Bit Set