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组网需求
当网络出现故障时,IS-IS Auto FRR可以将流量快速切换到备份链路上,而不用等待路由收敛,从而达到流量不中断的目的。
如图1所示,
四台NE之间运行IS-IS协议。
四台NE都是Level-1-2NE。
当DeviceC或链路T出现故障时,DeviceA转发的流量快速切换到备份链路上。
设备名称 | 接口 | IP地址 |
DeviceA | GE0/1/0 | 10.0.1.1/24 |
GE0/2/0 | 10.1.1.1/24 | |
DeviceB | GE0/1/0 | 10.1.1.2/24 |
GE0/2/0 | 10.2.1.1/24 | |
DeviceC | GE0/1/0 | 10.0.1.2/24 |
GE0/2/0 | 10.3.1.1/24 | |
DeviceD | GE0/1/0 | 10.3.1.2/24 |
GE0/2/0 | 10.2.1.2/24 | |
GE0/3/0 | 10.4.1.1/24 |
配置思路
采用如下思路配置IS-IS Auto FRR:
在各NE上使能IS-IS基本功能。
在DeviceA的GigabitEthernet0/2/0接口上配置较大开销(需满足IS-IS Auto FRR流量保护不等式),使流量优选链路T。
- 由于需保护的是DeviceA转发的流量,因此在DeviceA上使能IS-IS Auto FRR。
数据准备
为完成此配置例,需准备如下的数据:
各NE接口的IP地址;
各NE的NET;
各NE的级别;
各NE接口的开销。
操作步骤
- 配置各接口的IP地址(略)
- 配置IS-IS基本功能
# 配置DeviceA。
[~DeviceA] isis 1
[*DeviceA-isis-1] is-level level-1-2
[*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] quit
[*DeviceA] interface gigabitethernet 0/2/0
[*DeviceA-GigabitEthernet0/2/0] isis enable 1
[*DeviceA-GigabitEthernet0/2/0] commit
[~DeviceA-GigabitEthernet0/2/0] quit
# 配置DeviceB。
[~DeviceB] isis 1
[*DeviceB-isis-1] is-level level-1-2
[*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] quit
[*DeviceB] interface gigabitethernet 0/2/0
[*DeviceB-GigabitEthernet0/2/0] isis enable 1
[*DeviceB-GigabitEthernet0/2/0] commit
[~DeviceB-GigabitEthernet0/2/0] quit
# 配置DeviceC。
[~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] quit
[*DeviceC] interface gigabitethernet 0/2/0
[*DeviceC-GigabitEthernet0/2/0] isis enable 1
[*DeviceC-GigabitEthernet0/2/0] commit
[~DeviceC-GigabitEthernet0/2/0] quit
# 配置DeviceD。
[~DeviceD] isis 1
[*DeviceD-isis-1] is-level level-1-2
[*DeviceD-isis-1] network-entity 10.0000.0000.0004.00
[*DeviceD-isis-1] quit
[*DeviceD] interface gigabitethernet 0/1/0
[*DeviceD-GigabitEthernet0/1/0] isis enable 1
[*DeviceD-GigabitEthernet0/1/0] quit
[*DeviceD] interface gigabitethernet 0/2/0
[*DeviceD-GigabitEthernet0/2/0] isis enable 1
[*DeviceD-GigabitEthernet0/2/0] commit
[~DeviceD-GigabitEthernet0/2/0] quit
- 配置DeviceA的GigabitEthernet0/2/0接口开销为30,并查看路由信息。
# 配置DeviceA的GigabitEthernet0/2/0接口开销为30。
[~DeviceA] interface gigabitethernet 0/2/0
[~DeviceA-GigabitEthernet0/2/0] isis cost 30
[*DeviceA-GigabitEthernet0/2/0] commit
[~DeviceA-GigabitEthernet0/2/0] quit
# 查看DeviceA到DeviceD的链路信息。由于链路T的开销最小,因此,IS-IS优选链路T来传送DeviceA转发的流量。
[~DeviceA] display isis route verbose 10.4.1.1
Route information for ISIS(1)
-----------------------------
ISIS(1) Level-1 Forwarding Table
--------------------------------
IPV4 Dest : 10.4.1.0/24 Int. Cost : 30 Ext. Cost : NULL
Admin Tag : - Src Count : 2 Flags : A/-/L/-
Priority : -
NextHop : Interface : ExitIndex :
10.0.1.2 GE0/1/0 0x00000010
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 Dest : 10.4.1.0/24 Int. Cost : 30 Ext. Cost : NULL
Admin Tag : - Src Count : 2 Flags : -/-/-/-/-
Priority : -
NextHop : Interface : ExitIndex :
-
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
- 使能IS-IS Auto FRR
# 在DeviceA上使能IS-IS Auto FRR。
[~DeviceA] isis
[~DeviceA-isis-1] frr
[*DeviceA-isis-1-frr] loop-free-alternate
[*DeviceA-isis-1-frr] commit
[~DeviceA-isis-1-frr] quit
[~DeviceA-isis-1] quit
- 检查配置结果
# 查看DeviceA到DeviceD的路由信息。由于使能了IS-IS Auto FRR,IS-IS生成了一条备份路由。
[~DeviceA] display isis route verbose 10.4.1.1
Route information for ISIS(1)
-----------------------------
ISIS(1) Level-1 Forwarding Table
--------------------------------
IPV4 Dest : 10.4.1.0/24 Int. Cost : 30 Ext. Cost : NULL
Admin Tag : - Src Count : 2 Flags : A/-/L/-
Priority : -
NextHop : Interface : ExitIndex :
10.0.1.2 GE0/1/0 0x00000010
(B)10.1.1.2 GE0/1/0 0x0000000f(N)
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 Dest : 10.4.1.0/24 Int. Cost : 30 Ext. Cost : NULL
Admin Tag : - Src Count : 2 Flags : -/-/-/-/-
Priority : -
NextHop : Interface : ExitIndex :
-
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
配置文件
DeviceA的配置文件
#
sysname DeviceA
#
isis 1
network-entity 10.0000.0000.0001.00
frr
loop-free-alternate level-1
loop-free-alternate level-2
#
interface gigabitethernet 0/1/0
undo shutdown
ip address 10.0.1.1 255.255.255.0
isis enable 1
#
interface gigabitethernet 0/2/0
undo shutdown
ip address 10.1.1.1 255.255.255.0
isis enable 1
isis cost 30
#
return
DeviceB的配置文件
#
sysname DeviceB
#
isis 1
network-entity 10.0000.0000.0002.00
#
interface gigabitethernet 0/1/0
undo shutdown
ip address 10.1.1.2 255.255.255.0
isis enable 1
#
interface gigabitethernet 0/2/0
undo shutdown
ip address 10.2.1.1 255.255.255.0
isis enable 1
#
return
DeviceC的配置文件
#
sysname DeviceC
#
isis 1
network-entity 10.0000.0000.0003.00
#
interface gigabitethernet 0/1/0
undo shutdown
ip address 10.0.1.2 255.255.255.0
isis enable 1
#
interface gigabitethernet 0/2/0
undo shutdown
ip address 10.3.1.1 255.255.255.0
isis enable 1
#
return
DeviceD的配置文件
#
sysname DeviceD
#
isis 1
network-entity 10.0000.0000.0004.00
#
interface gigabitethernet 0/1/0
undo shutdown
ip address 10.3.1.2 255.255.255.0
isis enable 1
#
interface gigabitethernet 0/2/0
undo shutdown
ip address 10.2.1.2 255.255.255.0
isis enable 1
#
interface gigabitethernet 0/3/0
undo shutdown
ip address 10.4.1.1 255.255.255.0
isis enable 1
#
return