OSPFv2 Network and LSA Chart
| Area Type | Standard | Config | Auto Inject Default? | Type 1 | Type 2 | Type 3 | Type 4 | Type 5 | Type 7 |
|---|---|---|---|---|---|---|---|---|---|
| Backbone | RFC 2328 | area 0 |
No | ||||||
● default-information originate [always], creates an O E2 route, Type 5.● Can be linked thru other areas via Virtual Links. |
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| Regular Area | RFC 2328 | area 1 |
No | ||||||
| ● 1 area per WAN linked remote site, to prevent Type 1 and Type 2 flooding across WAN links. |
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| NSSA | RFC 3101 | area 2 nssa |
No | ||||||
| ● Uses the N-Bit (NSSA) and P-Bit (propagate). ● ABR can inject a Default route via area 3 nssa default-information-originate. Default is a Type 7. |
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| Stub | RFC 2328 | area 2 stub |
Yes | ||||||
● ABR automatically generates an O IA Type 3 default route. |
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| Totally Stubby NSSA | Cisco | area 2 nssa no-summary |
Yes | ||||||
● ABR gets no-summary, which generates an O IA Type 3 default route.● Allows internally originated external routes via Type 7. ● Other Type 3 blocked. |
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| Totally Stubby | Cisco | area 2 stub no-summary |
Yes | ||||||
● ABR gets no-summary, which generates an O IA Type 3 default route.● Other Type 3 blocked. |
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v3.1 (9-June-2026)