H3C Technologies H3C S7500E Series Switches - Manual (Page 130)

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Configuring an OSPF NSSA Area
Network requirements
The following figure shows an AS is split into three areas, where all switches run OSPF. Switch A and
Switch B act as ABRs to forward routing information between areas.
It is required to configure Area 1 as an NSSA area, and configure Router C as the ASBR to redistribute
static routes into the AS.
Figure 4-25 Network diagram for OSPF NSSA area configuration
Configuration procedure
1) Configure IP addresses for interfaces.
2) Configure OSPF basic functions (see Configuring OSPF Basic Functions ).
3) Configure Area 1 as an NSSA area.
# Configure Switch A.
[SwitchA] ospf
[SwitchA-ospf-1] area 1
[SwitchA-ospf-1-area-0.0.0.1] nssa default-route-advertise no-summary
[SwitchA-ospf-1-area-0.0.0.0] quit
[SwitchA-ospf-1] quit
# Configure Switch C.
[SwitchC] ospf
[SwitchC-ospf-1] area 1
[SwitchC-ospf-1-area-0.0.0.1] nssa
[SwitchC-ospf-1-area-0.0.0.1] quit
[SwitchC-ospf-1] quit
It is recommended to configure the nssa command with the keyword default-route-advertise
no-summary on Switch A (an ABR) to reduce the routing table size on NSSA routers. On other NSSA
routers, use the nssa command.
# Display OSPF routing information on Switch C.