CCNP - ENTERPRISE- OSPF - Network Types - Point-to-Multipoint

Point-to-Multipoint

• Full mesh not required
• Allows for NBMA networking
• No DR/BDR elections
• Timers = 30 seconds /120 seconds
• Do not need to manually configure neighbor statements
• Specific networks advertised through out.

Configuration:

Lacking a diagram, assume we have 4 routers in a hub and spoke design. R1 is the Hub and R2,R3, and R4 are spoke routers. Frame-relay is in use.

On R1:

R1(config)#router ospf 1

R1(config-router)#network 192.168.1.0 0.0.0.255 area 0

!

R1(config)#int s0/0

R1(config-if)#ip address 192.168.1.1 255.255.255.0

R1(config-if)#encapsulation frame-relay

R1(config-if)#ip ospf network point-to-multipoint

R1(config-if)#frame-relay map ip 192.168.1.2 102^

R1(config-if)#frame-relay map ip 192.168.1.3 103

R1(config-if)#frame-relay map ip 192.168.1.4 104

!

^ maps 192.168.1.2 to DLCI 102 - this is locally significant.

On R2:

R2(config)#router ospf 1

R2(config-router)#network 192.168.1.0 0.0.0.255 area 0

!

R2(config)#int s0/0

R2(config-if)#ip address 192.168.1.2 255.255.255.0

R2(config-if)#encapsulation frame-relay

R2(config-if)#ip ospf network point-to-multipoint

R2(config-if)#frame-relay map ip 192.168.1.1 25

R2(config-if)#frame-relay map ip 192.168.1.3 25

R2(config-if)#frame-relay map ip 192.168.1.4 25

!

On R3:

R3(config)#router ospf 1

R3(config-router)#network 192.168.1.0 0.0.0.255 area 0

!

R3(config)#int s0/0

R3(config-if)#ip address 192.168.1.3 255.255.255.0

R3(config-if)#encapsulation frame-relay

R3(config-if)#ip ospf network point-to-multipoint

R3(config-if)#frame-relay map ip 192.168.1.1 35

R3(config-if)#frame-relay map ip 192.168.1.2 35

R3(config-if)#frame-relay map ip 192.168.1.4 35

!

On R4:

R4(config)#router ospf 1

R4(config-router)#network 192.168.1.0 0.0.0.255 area 0

!

R4(config)#int s0/0

R4(config-if)#ip address 192.168.1.4 255.255.255.0

R4(config-if)#encapsulation frame-relay

R4(config-if)#ip ospf network point-to-multipoint

R4(config-if)#frame-relay map ip 192.168.1.1 45

R4(config-if)#frame-relay map ip 192.168.1.2 45

R4(config-if)#frame-relay map ip 192.168.1.3 45

!

Note - the lack of manually assigned neighbor statements and the fact you still need to configure your frame-relay maps.

-Also do not forget the ip ospf network point-to-multipoint cmd.