[hcie TAC] question 3

subject ：AR32 loopback 0 cannot access ISIS All routes of the zone .

One 、 Fault root cause judgment
AR32 loopback 0 cannot access ISIS The root cause of all routes in the region is ,AR28 In connection AR32 Of g 2/0/0 The interface is targeted at OSPF Of 5 class LSA Filter .

Two 、 Fault analysis ：

2.1、 stay AR32 On the implementation ping -a 10.5.1.32 x.x.x.x （ among x.x.x.x yes ISIS All routes of the zone ）, It is found that there are inaccessible ISIS Failure of all routes in the area . Need to view AR32 Whether there is ISIS Relevant routing information of regional equipment .

2.2、 stay AR32 On the implementation display ip routing-table command , see AR32 Routing table information for , The output is as follows ：

    <AR32>display ip routing-table 
     Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
     Routing Tables: Public
     Destinations : 14       Routes : 14       

Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface

  10.5.1.27/32  OSPF    10   2           D   10.5.239.28     GigabitEthernet0/0/0
  10.5.1.28/32  OSPF    10   1           D   10.5.239.28     GigabitEthernet0/0/0
  10.5.1.29/32  OSPF    10   2           D   10.5.239.28     GigabitEthernet0/0/0
  10.5.1.32/32  Direct  0    0           D   127.0.0.1       LoopBack0
  10.5.1.33/32  OSPF    10   3           D   10.5.239.28     GigabitEthernet0/0/0
  10.5.40.0/24  OSPF    10   3           D   10.5.239.28     GigabitEthernet0/0/0
 10.5.128.0/24  OSPF    10   2           D   10.5.239.28     GigabitEthernet0/0/0

From the output results AR32 There is nothing in the routing table of ISIS Related routing entries of the region , But there is AR28 loopback0 Routing information for , explain AR28 And AR32 Of OSPF The neighborhood relationship is established normally . because OSPF The agreement is through LSA To transmit routing information , So I need to check AR32 Of LSDB Does the database have ISIS Regional 5 class LSA.

2.3、 stay AR32 On the implementation display ospf lsdb command , see AR32 Of LSDB Does the database have ISIS Regional 5 class LSA, The output is as follows ：

<AR32>dis ospf lsdb

 OSPF Process 1 with Router ID 10.5.1.32
	 Link State Database 

	         Area: 0.0.0.1
Type      LinkState ID    AdvRouter          Age  Len   Sequence   Metric
Router    10.5.1.32       10.5.1.32          205  48    80000006       1
Router    10.5.1.28       10.5.1.28          214  36    80000004       1
Network   10.5.239.32     10.5.1.32          205  32    80000002       0
Sum-Net   10.5.128.0      10.5.1.28          252  28    80000001       1
Sum-Net   10.5.1.29       10.5.1.28          212  28    80000001       1
Sum-Net   10.5.1.28       10.5.1.28          252  28    80000001       0
Sum-Net   10.5.1.27       10.5.1.28          212  28    80000001       1
Sum-Net   10.5.40.0       10.5.1.28          212  28    80000001       2
Sum-Asbr  10.5.1.29       10.5.1.28          212  28    80000001       1
Sum-Asbr  10.5.1.27       10.5.1.28          212  28    80000001       1

From the output results ,AR32 Of LSDB There is no ISIS Regional 5 class LSA, The preliminary judgment may be AR28 Upper not ISIS The process is introduced into OSPF In progress , because OSPF Agreed 5 class LSA It is flooding to the whole OSPF In domain , also AR32 And AR27、AR29 Of OSPF Neighborhood relations are established normally , So you can view AR27 and AR29 Of LSDB Whether there is ISIS Regional 5 class LSA To judge AR28 Whether it will ISIS The process is introduced into OSPF In progress .

2.4、 stay AR27 and AR29 On the implementation display ospf lsdb command , see OSPF Of LSDB Whether there is... In the data ISIS Regional 5 class LSA, The output is as follows ：

<AR27>display ospf lsdb 

 OSPF Process 1 with Router ID 10.5.1.27
	 Link State Database 

	         Area: 0.0.0.0
 Type      LinkState ID    AdvRouter          Age  Len   Sequence   Metric
Router    10.5.1.27       10.5.1.27         1183  48    80000013       1
Router    10.5.1.29       10.5.1.29         1184  36    80000011       1
Router    10.5.1.28       10.5.1.28         1183  48    80000014       1
Network   10.5.128.30     10.5.1.29         1184  36    8000000C       0
Sum-Net   10.5.1.33       10.5.1.29         1432  28    80000002       1
Sum-Net   10.5.1.32       10.5.1.28         1159  28    80000001       1
Sum-Net   10.5.1.29       10.5.1.29         1438  28    80000002       0
Sum-Net   10.5.239.0      10.5.1.28         1185  28    80000003       1
Sum-Net   10.5.40.0       10.5.1.29         1438  28    80000002       1

	 AS External Database
Type      LinkState ID    AdvRouter          Age  Len   Sequence   Metric
External  10.5.1.31       10.5.1.28         1185  36    80000004       1
External  10.5.1.30       10.5.1.28         1185  36    80000004       1
External  10.5.1.34       10.5.1.28         1185  36    80000004       1
External  10.5.14.0       10.5.1.28         1185  36    80000004       1
External  10.5.34.0       10.5.1.28         1185  36    80000004       1
External  10.5.130.0      10.5.1.28         1185  36    80000004       1
External  10.5.129.0      10.5.1.28         1185  36    80000004       1
-------------------------------------------------------------------------------
<AR29>display ospf lsdb 

 OSPF Process 1 with Router ID 10.5.1.29
	 Link State Database 

	         Area: 0.0.0.0
Type      LinkState ID    AdvRouter          Age  Len   Sequence   Metric
Router    10.5.1.27       10.5.1.27         1249  48    80000013       1
Router    10.5.1.29       10.5.1.29         1248  36    80000011       1
Router    10.5.1.28       10.5.1.28         1248  48    80000014       1
Network   10.5.128.30     10.5.1.29         1248  36    8000000C       0
Sum-Net   10.5.1.33       10.5.1.29         1496  28    80000002       1
Sum-Net   10.5.1.32       10.5.1.28         1224  28    80000001       1
Sum-Net   10.5.1.29       10.5.1.29         1502  28    80000002       0
Sum-Net   10.5.239.0      10.5.1.28         1250  28    80000003       1
 Sum-Net   10.5.40.0       10.5.1.29         1502  28    80000002       1

	         Area: 0.0.0.2
Type      LinkState ID    AdvRouter          Age  Len   Sequence   Metric
Router    10.5.1.33       10.5.1.33         1486  48    80000007       1
Router    10.5.1.29       10.5.1.29         1497  48    80000006       1
Network   10.5.40.34      10.5.1.33         1486  32    80000003       0
Sum-Net   10.5.128.0      10.5.1.29         1502  28    80000002       1
Sum-Net   10.5.1.32       10.5.1.29         1223  28    80000001       2
Sum-Net   10.5.1.28       10.5.1.29         1246  28    80000001       1
Sum-Net   10.5.1.27       10.5.1.29          137  28    80000003       1
Sum-Net   10.5.239.0      10.5.1.29         1246  28    80000001       2
 NSSA      0.0.0.0         10.5.1.29         1464  36    80000002       1

	 AS External Database
Type      LinkState ID    AdvRouter          Age  Len   Sequence   Metric
External  10.5.1.31       10.5.1.28         1250  36    80000004       1
External  10.5.1.30       10.5.1.28         1250  36    80000004       1
External  10.5.1.34       10.5.1.28         1250  36    80000004       1
External  10.5.14.0       10.5.1.28         1250  36    80000004       1
External  10.5.34.0       10.5.1.28         1250  36    80000004       1
External  10.5.130.0      10.5.1.28         1250  36    80000004       1
External  10.5.129.0      10.5.1.28         1250  36    80000004       1

From the output results ,AR27 And AR29 Of LSDB There is... In the database ISIS Regional 5 class LSA, explain AR28 Admiral ISIS The process is introduced into OSPF In progress , because AR28 Upper not OSPF The process is introduced into ISIS This fault phenomenon will also be caused in the process , So I need to check ISIS Whether there is OSPF Routing information of the area .

2.5、 stay AR32 and AR34 On the implementation display routing-table command , See if it exists OSPF Area routing , The output is as follows

<AR31>display ip routing-table
     Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
     Routing Tables: Public
     Destinations : 23       Routes : 23       

 Destination/Mask    Proto   Pre  Cost      Flags NextHop        Interface

  10.5.1.27/32  ISIS-L2 15   74          D   10.5.130.28     GigabitEthernet0/0/2
  10.5.1.28/32  ISIS-L2 15   74          D   10.5.130.28     GigabitEthernet0/0/2
  10.5.1.29/32  ISIS-L2 15   74          D   10.5.130.28     GigabitEthernet0/0/2
  10.5.1.30/32  ISIS-L1 15   20          D   10.5.14.34      GigabitEthernet0/0/1
  10.5.1.31/32  Direct  0    0           D   127.0.0.1       LoopBack0
  10.5.1.32/32  ISIS-L2 15   74          D   10.5.130.28     GigabitEthernet0/0/2
  10.5.1.33/32  ISIS-L2 15   74          D   10.5.130.28     GigabitEthernet0/0/2
  10.5.1.34/32  ISIS-L1 15   10          D   10.5.14.34      GigabitEthernet0/0/1
  10.5.14.0/24  Direct  0    0           D   10.5.14.31      GigabitEthernet0/0/1
  10.5.14.31/32  Direct 0    0           D   127.0.0.1       GigabitEthernet0/0/1
  10.5.14.255/32  Direct0    0           D   127.0.0.1      GigabitEthernet0/0/1
  10.5.34.0/24  ISIS-L1 15   20          D   10.5.14.34      GigabitEthernet0/0/1
  10.5.40.0/24  ISIS-L2 15   74          D   10.5.130.28     GigabitEthernet0/0/2
  10.5.128.0/24  ISIS-L2 15   74          D   10.5.130.28    GigabitEthernet0/0/2

<AR34>display  ip routing-table
     Route Flags: R - relay, D - download to fib
-----------------------------------------------------------------------------
     Routing Tables: Public
     Destinations : 16       Routes : 17       

Destination/Mask    Proto   Pre  Cost      Flags NextHop        Interface

    0.0.0.0/0   ISIS-L1 15   10          D   10.5.14.31      GigabitEthernet0/0/1
                ISIS-L1 15   10          D   10.5.34.30      GigabitEthernet0/0/0
  10.5.1.30/32  ISIS-L1 15   10          D   10.5.34.30      GigabitEthernet0/0/0
  10.5.1.31/32  ISIS-L1 15   10          D   10.5.14.31      GigabitEthernet0/0/1
  10.5.1.34/32  Direct  0    0           D   127.0.0.1       LoopBack0
  10.5.14.0/24  Direct  0    0           D   10.5.14.34      GigabitEthernet0/0/1
  10.5.14.34/32  Direct 0    0           D   127.0.0.1       GigabitEthernet0/0/1
  10.5.14.255/32  Direct0    0           D   127.0.0.1      GigabitEthernet0/0/1
  10.5.34.0/24  Direct  0    0           D   10.5.34.34      GigabitEthernet0/0/0
  10.5.34.34/32  Direct 0    0           D   127.0.0.1       GigabitEthernet0/0/0
  10.5.34.255/32  Direct0    0           D   127.0.0.1      GigabitEthernet0/0/0
  10.5.129.0/24  ISIS-L1 15   20          D   10.5.34.30     GigabitEthernet0/0/0
  10.5.130.0/24  ISIS-L1 15   20          D   10.5.14.31     GigabitEthernet0/0/1

From the output results ,AR31 In the routing table of OSPF All routes of the zone ,AR34 There are two default routes on , The next jump points to AR30 and AR31, explain AR28 Admiral OSPF The process is introduced into ISIS In progress , Need to check AR31、AR32、AR34 Whether there is a filtering strategy that causes failure on .

2.6、 stay AR31、AR32、AR34 On the implementation display ip ip-prefix,display acl all,display traffic-filter applied-record
、display traffic-policy applied-record 、display route-policy command , No filtering strategy that can lead to modification failure has been found .

in summary ：AR27 and AR29 Of LSDB There exists in the database ISIS Regional 5 class LSA,ISIS Regional AR31 In the routing table of OSPF Routing information of the area , explain AR28 I did OSPF and ISIS Two way introduction of , Check AR31、AR32、AR34 There is no filtering strategy that can cause failure . So the judgment is AR28 In connection AR32 Of g2/0/0 The interface is targeted at OSPF Of 5 class LSA Filter .

3、 ... and 、 Trouble shooting

3.1、 stay AR28 Delete... On g 2/0/0 Filter commands on the interface , The specific operation is as follows ：

system-view                      # Enter the system view 
int g2/0/0                       # Enter the interface view 
undo ospf filter-lsa-out         # Delete the filter command 
 After the execution of the above order AR32 Execute the following command on , To check whether the fault has been solved ：
display ospf lsdb                 # see ospf  Of LSDB Whether there is ISI Regional 5 class LSA
display ip routing-table          # Check whether there is ISIS Area routing 
ping -a 10.5.1.32 x.x.x.x {x.x.x.x yes ISIS All routes of the zone }  # Test and ISIS Routing connectivity of the region .

3.2、 Other high probability errors —— stay AR28 There is a target on ISIS Filtering strategy of regional traffic , Execute the following command to solve the problem ：

display traffic-filter applied-record     # Check whether there is traffic filtering 
display traffic-policy applied-record     # Check whether there is a traffic policy 
system-view                               # Enter the system view 
int { Configure the interface of traffic filtering strategy }               # Enter the interface view 
undo traffic-filter inbound/outbound      # Delete traffic filtering 
undo traffic-policy inbound/outbound      # Delete traffic policy 
 After the execution of the above order AR32 Execute the following command on , To check whether the fault has been solved ：
display ospf lsdb                 # see ospf  Of LSDB Whether there is ISI Regional 5 class LSA
display ip routing-table          # Check whether there is ISIS Area routing 
ping -a 10.5.1.32 x.x.x.x {x.x.x.x yes ISIS All routes of the zone }  # Test and ISIS Routing connectivity of the region .

If after executing the above command , The problem is still unresolved , Please send a front-line engineer to the site to remove obstacles , Or provide complete equipment configuration information , And call Huawei 400 Hotline , Ask Huawei experts for assistance .