cisco abr asbr

HOW TO ABR AND ASBR CONFIGURATION

Cisco Routing Network Administrator
 ABR and ASBR Configure on cisco
Interface IP Address Configuration  
  
R1  
Interface    IP Address  Subnet Mask
S0/2/0       1.1.1.1           255.0.0.0
E0             10.1.1.1         255.0.0.0
R2  
Interface    IP Address  Subnet Mask
S0              1.1.1.2          255.0.0.0
S1              2.2.2.1          255.0.0.0
E0              20.1.1.1        255.0.0.0
R3  
Interface   IP Address   Subnet Mask
S0              2.2.2.2          255.0.0.0
E 0             30.1.1.1        255.0.0.0
Task 1   
Configure OSPF in Area 0 on R1 ( S0/2/0, E0 ),  R2 ( S0 )
Configure OSPF in Area 1 on R2 ( S1 ), R3 ( S0, E 0 ).
Configure EIGRP AS 100 on R2 ( E0 ) and redistribute into OSPF.
R1                                                                 
Router ospf 1
Network 1.1.1.1 0.0.0.0 area 0
Network 10.0.0.0 0.255.255.255 area 0
R2
Router ospf 1
Network 2.2.2.1 0.0.0.0 area 1
Network 1.1.1.2 0.0.0.0 area 0
Router eigrp 100
Network 20.0.0.0
No auto-summary
Router ospf 1
Redistribute eigrp 100 metric 10 subnets
R3                                                                 
Router ospf 1
Network 2.2.2.2 0.0.0.0 area 1
Network 30.0.0.0 0.255.255.255 area 1
Verification:  
R1#show ip route
The output displays ‘O’ and ‘O IA’ routes.
The output also shows that network 20.0.0.0 is missing in the routing table.
As EIGRP is a NON-OSPF routing protocol, we need to redistribute EIGRP into OSPF
R1#show ip route
Note:  If we want OE1 routes then the redistribute command should be configured using
metric-type
R2  
Router ospf 1
Redistribute eigrp 100 metric-type 1 metric
10 subnets
R1#show ip route
To verify which router is ABR / ASBR : –
R1 # show ip ospf border-routers
OSPF Process 1 internal Routing Table
Codes: i – Intra-area route, I – Inter-area route
i 20.1.1.1 [64] via 1.1.1.2, Serial0/2/0, ABR/ASBR, Area 0, SPF

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