3Com 4210 # Configure area 1 as an Nssa area, Nssa area configuration 2 area 1 is an Nssa area

114CHAPTER 15: ROUTING CONFIGURATION GUIDE

#Configure area 1 as an NSSA area.

[SwitchA-ospf-1-area-0.0.0.1] nssa

[SwitchC-ospf-1-area-0.0.0.1] nssa

n ■ The steps above configure an NSSA area.

■Use the display ospf lsdb command on Switch C to display the LSDB. You can see that no Type-4 LSAs or Type-5 LSAs exist in the LSDB. But Type-7 LSAs are installed.

NSSA area configuration 2 (area 1 is an NSSA area)

n After this configuration, packets from the NSSA area to other ASs are forwarded by the ASBR of the NSSA area.

Based on the configuration in “Non-backbone area and backbone area configuration (area 1 is a non-backbone area)” on page 107, perform the following steps:

# Configure a default route.

[SwitchC] ip route-static 0.0.0.0 0.0.0.0 10.4.1.2

#Configure Area 1 as an NSSA area. Switch C will forward all the packets to other ASs.

[SwitchA-ospf-1-area-0.0.0.1] nssa

[SwitchC-ospf-1-area-0.0.0.1] nssa default-route-advertise

n ■ The steps above configure an NSSA area.

■Use the display ospf lsdb command on Switch C to display the LSDB. You can see that no Type-4 LSAs or Type-5 LSAs exist in the LSDB. But Type-7 LSAs and a Type-7 default LSA are added.

NSSA area configuration 3 (area 1 is an NSSA area)

n After this configuration, packets destined for an IP address (in another AS) advertised by the ASBR of the NSSA area will be forwarded by the ASBR, while packets destined for an IP address (in another AS) not advertised by the ASBR will be forward by the ABR of the area to the ASBR of another area for further forwarding.

Based on the configuration in “Non-backbone area and backbone area configuration (area 1 is a non-backbone area)” on page 107, perform the following steps:

# Configure area 1 as an NSSA area.

[SwitchA-ospf-1-area-0.0.0.1] nssa default-route-advertise

[SwitchC-ospf-1-area-0.0.0.1] nssa

n ■ The steps above configure an NSSA area.