How do you perform an inter-area summarization in OSPF?
To summarize routes sent to the backbone area:
- Configure the interfaces.
- Configure the type of OSPF area.
- Assign the interfaces to the OSPF areas.
- Summarize the routes that are flooded into the backbone.
- On ABR R3, restrict the external static route from leaving area 0.0.
What is OSPF route summarization?
Route summarization helps reduce OSPF traffic and route computation. OSPF, unlike EIGRP, doesn’t support automatic summarization. Also, unlike EIGRP, where you can summarize routes on every router in an EIGRP network, OSFP can summarize routes only on ABRs and ASBRs.
What is inter-area OSPF?
Inter-Area: When a route crosses an OSPF Area Border Router (ABR), the route is known as an OSPF Inter-Area route. A Type-1 cost is the addition of the external cost and the internal cost used to reach that route. A Type-1 route is always preferred over a Type-2 route for the same destination.
What does Inter area mean?
interarea (not comparable) Between areas.
What is DR and BDR in OSPF?
In an OSPF broadcast network, OSPF elects one router to serve as the designated router (DR) and another router on the segment to act as the backup designated router (BDR). This minimizes the amount of repetitive information that is forwarded on the network. OSPF forwards all messages to the designated router.
Which is route summarization protocol does OSPF use?
OSPF is link state routing protocol that works on the concept of areas. All areas must have same LSDB (link state database); hence OSPF summarization can only done on the border routers i.e. on ABR (Area border router) and ASBR (Autonomous system boundary router).In this document we discussed about route summarization between the areas.
Can you do external summarization in OSPF?
However when working with OSPF you can only summarize at an ABR or ASBR. There are two types of summarization in OSPF; Inter-Area Summarization and External Summarization. Inter-Area route summarization can only be done on the Area Boarder Router (ABR) and summarize routes from a particular area into the backbone area.
Can a route summarization be done on an ASBR?
Inter-Area route summarization can only be done on the Area Boarder Router (ABR) and summarize routes from a particular area into the backbone area. External Route summarization can only be done on an ASBR and summarizes routes to an external destination.
What kind of LSA type does OSPF use?
If you are studying OSPF you will learn that OSPF uses LSA type 3 for inter-area routers and LSA type 5 for external prefixes that are redistributed into OSPF. OSPF can do summarization but it’s impossible to summarize within an area.