Filtering Type 3 LSA (2) on the abr in the ospf Environment)

LSA for filtering Type 3 in the OSPF environment-test

Test-check the content of the ospf database before applying LSA filtering.

 
 

  
  
R1#show ip ospf database  
  
  
 
  
  
OSPF Router with ID (1.1.1.1) (Process ID 1)  
  
  
 
  
  
Router Link States (Area 0)  
  
  
 
  
  
Link ID         ADV Router      Age         Seq#       Checksum Link count  
  
  
1.1.1.1         1.1.1.1         21          0x80000004 0x0010BC 1  
  
  
2.2.2.2         2.2.2.2         21          0x80000002 0x00D5EF 1  
  
  
 
  
  
Net Link States (Area 0)  
  
  
 
  
  
Link ID         ADV Router      Age         Seq#       Checksum  
  
  
10.1.1.2        2.2.2.2         21          0x80000001 0x002CEB  
  
  
 
  
  
Summary Net Link States (Area 0)  
  
  
 
  
  
Link ID         ADV Router      Age         Seq#       Checksum  
  
  
192.168.1.0     1.1.1.1         161         0x80000001 0x00B815  
  
  
192.168.2.0     1.1.1.1         161         0x80000001 0x00AD1F  
  
  
192.168.3.0     1.1.1.1         161         0x80000001 0x00A229  
  
  
192.168.4.0     2.2.2.2         352         0x80000001 0x00794D  
  
  
192.168.5.0     2.2.2.2         352         0x80000001 0x006E57  
  
  
192.168.6.0     2.2.2.2         352         0x80000001 0x006361  
  
  
 
  
  
Router Link States (Area 1)  
  
  
 
  
  
Link ID         ADV Router      Age         Seq#       Checksum Link count  
  
  
1.1.1.1         1.1.1.1         161         0x80000004 0x00CFF1 3  
  
  
 
  
  
Summary Net Link States (Area 1)  
  
  
 
  
  
Link ID         ADV Router      Age         Seq#       Checksum  
  
  
10.1.1.0        1.1.1.1         17          0x80000003 0x00509A  
  
  
192.168.4.0     1.1.1.1         12          0x80000001 0x001A70  
  
  
192.168.5.0     1.1.1.1         12          0x80000001 0x000F7A  
  
  
192.168.6.0     1.1.1.1         12          0x80000001 0x000484 
 
 

It is found that there are 6 lsws of Type 3 in Area 0, which are advertised by R1 and R2. There are four LSAs for Type 3 of Area 1, which are all advertised by R1.

Test-view the R1 route table

 
 

  
  
R1#show ip route ospf  
  
  
O IA 192.168.4.0/24 [110/65] via 10.1.1.2, 00:03:20, Serial0  
  
  
O IA 192.168.5.0/24 [110/65] via 10.1.1.2, 00:03:20, Serial0  
  
  
O IA 192.168.6.0/24 [110/65] via 10.1.1.2, 00:03:20, Serial0 
 
 

Three Inter-region routes are found

Test-apply LSA filter on R1

Currently, LSA is applied to R1 to filter in area 1. LSA with the prefix of 192.168.4.0/24 is allowed to restrict other prefixes.

 
 

  
  
R1(config)#ip prefix-list lsa3in permit 192.168.4.0/24  
  
  
R1(config-router)#area 1 filter-list prefix lsa3in in 
 
 

View the R1 Database

 
 

  
  
R1#show ip ospf database  
  
  
 
  
  
OSPF Router with ID (1.1.1.1) (Process ID 1)  
  
  
 
  
  
Router Link States (Area 0)  
  
  
 
  
  
Link ID         ADV Router      Age         Seq#       Checksum Link count  
  
  
1.1.1.1         1.1.1.1         568         0x80000004 0x0010BC 1  
  
  
2.2.2.2         2.2.2.2         568         0x80000002 0x00D5EF 1  
  
  
 
  
  
Net Link States (Area 0)  
  
  
 
  
  
Link ID         ADV Router      Age         Seq#       Checksum  
  
  
10.1.1.2        2.2.2.2         569         0x80000001 0x002CEB  
  
  
 
  
  
Summary Net Link States (Area 0)  
  
  
 
  
  
Link ID         ADV Router      Age         Seq#       Checksum  
  
  
192.168.1.0     1.1.1.1         709         0x80000001 0x00B815  
  
  
192.168.2.0     1.1.1.1         709         0x80000001 0x00AD1F  
  
  
192.168.3.0     1.1.1.1         709         0x80000001 0x00A229  
  
  
192.168.4.0     2.2.2.2         900         0x80000001 0x00794D  
  
  
192.168.5.0     2.2.2.2         900         0x80000001 0x006E57  
  
  
192.168.6.0     2.2.2.2         900         0x80000001 0x006361  
  
  
 
  
  
Router Link States (Area 2)  
  
  
 
  
  
Link ID         ADV Router      Age         Seq#       Checksum Link count  
  
  
1.1.1.1         1.1.1.1         709         0x80000004 0x00CFF1 3  
  
  
 
  
  
Summary Net Link States (Area 2)  
  
  
 
  
  
Link ID         ADV Router      Age         Seq#       Checksum  
  
  
192.168.4.0     1.1.1.1         554         0x80000001 0x001A70 
 
 

It is found that all the six types of 3 in Region 0 are located, while the LSA of Type 3 in Region 2 only has one 192.168.4.0, which is allowed in the prefix list.

View R1 route table

 
 

  
  
R1#show ip route ospf  
  
  
O IA 192.168.4.0/24 [110/65] via 10.1.1.2, 00:05:04, Serial0  
  
  
O IA 192.168.5.0/24 [110/65] via 10.1.1.2, 00:05:04, Serial0  
  
  
O IA 192.168.6.0/24 [110/65] via 10.1.1.2, 00:05:04, Serial0 
 
 

Filtering LSA 1 of Type 3 on the ABR in OSPF environment)

Filtering LSA 3 of Type 3 on the abr in the ospf environment)

1. Analysis of multicast knowledge in IGMP V2 package
2. Horizontal split-by-the-command-by-product
3. Instance resolution: the floating summary routing configuration of the VPN gateway.
4. Router POS access technology and Solutions
5. Analysis of multicast knowledge-Layer 2 device forwarding Multicast