Blueprint (CCIE R&S), Certification
No Comments OSPF
| LSA Type | Advertising Router | Routing Table | DB | Summary | Filter | Comments |
|---|---|---|---|---|---|---|
| 1 - Router (Intra Area) | All | O | sh ip ospf data router | Lists neighbouring routers and the cost to each (flooded within an area) | ||
| 2 - Pseudonode (Intra Area) | DR | O | sh ip ospf data network | Generated by DR it lisst all routers on an adjacent segment (flooded within an area) | ||
| 3 - Network Summary (Inter Area) | ABR | IA | sh ip ospf data summary | Generated by an ABR and advertised among areas | ||
| 4 - ASBR Summary (Inter Area) | ABR | N/A | sh ip ospf data asbr-summary | Injected by an ABR into the backbone to advertise the presence of an ASBR within an area. (not really used anywhere) |
||
| 5 - External Link (External) | ASBR | Default = E2 Can be E1 | sh ip ospf data external | Generated by an ASBR and flooded throughout the AS to advertise a route external to OSPF | ||
| 6 - MOSPF | N/A | N/A | N/A | Not supported with Cisco | ||
| 7 - NSSA External Link(External) | ASBR in NSSA | Default = N2 Can be N1 | sh ip ospf data nssa-external | Generated by an ASBR in a not-so-stubby area; converted into a type 5 LSA by the ABR when leaving the area |
- OSPF External Type1 (E1) routes
- Include the external cost as well as the internal cost to the ASBR.
- Used to exit the AS as close as possible to the destination.
- Mostly used if multiple exit points out an AS exist.
- OSPF External Type2 (E2) routes:
- Include only the external cost of the route.
- Used to exit the AS via closest ASBR.
- Often used with only one OSPF exit point.