An NSSA is defined as an OSPF area where the ABR disallows Type 5 external LSAs while allowing the existence of an Autonomous System Border Router (ASBR). This allowance makes such an area “not as stubby” as a stub area or a totally stub area both of …

Mar 14, 2024 · The OSPF Not-So-Stubby Area (NSSA) feature is described by RFC 1587 and is first introduced in Cisco IOS Software release 11.2. It is a non-proprietary extension of the current stub area feature that allows the injection of external routes in a limited fashion into the stub area.

Nov 10, 2018 · OSPF stubs reduce memory consumption and CPU processing time on the routers inside the area because the routers in that area can have fewer LSAs in their LSDBs. If you configure a stub area it will block all type 5 external LSAs (E1 and E2 routes).

Nov 19, 2024 · You can use an NSSA to introduce external routes into a stub area without converting it into a standard OSPF area. Since a stub area filters LSA type 5 and external routes use LSA type 5, NSSA routers convert Type 5 LSAs into Type 7 …

2 days ago · NSSA stands for Not-So-Stubby Area, a type of OSPF area that combines features of stub and non-stub areas. It allows external routes to enter the area but limits their propagation to reduce routing information overhead.

OSPF totally NSSA area is a specific area type that does not allow LSA types 3, 4, and 5. It does permit redistribution of external routes using Type 7 LSAs like NSSA areas. In other words, routers in an entire NSSA (not-so-stubby area) area accept only LSA Type 7 …

Jun 14, 2020 · NSSA stands for not-so-stubby area and is used in OSPF protocol. NSSA is to allow OSPF Stub areas to carry External routes which is the routes learned from other protocols like RIP, EIGRP or BGP and then redistribution into an NSSA area creates a special type of link-state advertisement (LSA) known as type 7, which can only exist in an NSSA area.

May 29, 2024 · This guide delves into the basics of OSPF NSSA, elucidating why it is favored in certain network design scenarios and how it seamlessly integrates with standard OSPF to optimize performance. What is OSPF NSSA?

May 29, 2024 · NSSA is used in scenarios where external routes need to be redistributed into the OSPF domain but preventing these routes from flooding the entire network. NSSA introduces a new type of LSA, Type 7, which is converted into a Type 5 LSA by the ABR before being propagated to other areas.

OSPF NSSA areas can be useful if you need to separate or decrease the routing data sent throughout your network while maintaining ASBR support. This tutorial describes Open Shortest Path First (OSPF) Not-so-stubby Area (NSSA) areas, how they work, and how to configure them.