What is OSPF external type1?

OSPF supports two types of external metrics: Type 1 and Type 2. The difference between the two metrics is how OSPF calculates the cost of the route. Type 1 external metrics are equivalent to the link-state metric, where the cost is equal to the sum of the internal costs plus the external cost.

What is O E1 or E2 letters in OSPF which is default external type 1 or external type 2?

External Type-2 or External Type-1—Routes which were redistributed into OSPF, such as Connected, Static, or other Routing Protocol, are known as External Type-2 or External Type-1. These routes are flagged as O E2 or O E1 in the show ip route command output. External Type-2 is the default.

What is Type 1 and type 2 in OSPF?

A type 1 route has a metric that is the sum of the internal OSPF cost and the external redistributed cost. A type 2 route has a metric equal only to the redistributed cost, as shown in Figure 14-2.

What are N1 and n2 routes in OSPF?

OE1 or OE2 both are represented by LSA type 5 in the OSPF database. Now in a special OSPF area, NSSA or Totally NSSA the LSA type 5 cannot be propagated. Hence a new LSA type 7 is propagated in these areas by the respective ABR for that area.

What is the difference between OSPF external type 1 and type 2?

A type 1 route has a more accurate path info since it adds the costs on links inside the OSPF network to the cost of the external link. A type 2 route only has the cost of the external link no matter how many links it passes through in the internal network.

What is a NSSA area?

NSSA (Not so stubby area) is an OSPF area type that allows the injection of external routes into the stub area by using a special LSA type called LSA type 7.

What is the difference OSPF E1 & E2?

Basically the difference between E1 and E2 external routes is: E1 includes – the internal cost to ASBR added to the external cost, E2 does not include – internal cost. it is same as external cost.

Where is external Type 1 metric useful?

External Type 1 will add up the cost of each link to the ASBR originating, this is useful if you want to use the most optimal path to the exit point.

What is the difference between OSPF v1 and OSPFv2?

OSPFv2 stands for Open Shortest Path First version 2 and OSPFv3 stands for Open Shortest Path First version 3. OSPFv2 is the IPv4’s OSPF version, whereas OSPFv3 is the IPv6’s OSPF version. In OSPFv2, many OSPF instances per interface are not supported, whereas in OSPFv3, many OSPF instances per interface are supported.

What are OSPF E1 and E2 routes?

E2 routes have a default fixed cost of 20 associated with them, but this value can be changed with the metric keyword. The metric will not change as the route is propagated throughout the OSPF area. E1 routes will have internal area costs added to the seed metric.

What is the difference between ABR and Asbr?

ABR is used to connect the backbone area and non-backbone area. It could be a physical connection or a logical connection between non-backbone area and the backbone area. ASBR is a device to exchange routing information with other AS. It may be a router in the region or ABR.

What is the NSSA in OSPF?

NSSA is an OSPF Stub Area, which can carry routes learned by other protocols such as BGP or RIP. Allows the import of external routes in a limited fashion using Type-7 LSAs. NSSA border routers translate selected Type 7 LSAs into Type 5 LSAs, which can then be flooded to all Type-5 capable areas.