A totally stubby area (TSA) is a stub area in which summary link-state advertisement (type 3 LSAs) are not sent. The ABR of a totally stubby area disables origination of summary LSAs into this area, but still accepts summary LSAs from OSPF neighbors and floods them to other neighbors.
What is totally not-so-stubby area in OSPF?
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 existing stub area feature that allows the injection of external routes in a limited fashion into the stub area.
What is stub area flag in OSPF?
Stub area flag is used to communicate between adjacent nodes if one of them is in a stub area. To form an adjacency, both need to agree on that point. Stub configuration is not a requirement, but helps in large network designs.
What types of routers are allowed in totally stubby areas?
Totally stubby areas can only contain type 1 and 2 LSAs, and a single type 3 LSA. The type 3 LSA describes a default route, substituted for all external and inter-area routes. Not-so-stubby areas implement stub or totally stubby functionality yet contain an ASBR.
How do I set totally stubby area in OSPF?
To configure OSPF stub areas:
On all routing devices in the area, configure an OSPF stub area.
On the ABR, inject a default route into the area.
(Optional) On the ABR, restrict summary LSAs from entering the area.
If you are done configuring the devices, commit the configuration.
What is the purpose of OSPF?
The OSPF (Open Shortest Path First) protocol is one of a family of IP Routing protocols, and is an Interior Gateway Protocol (IGP) for the Internet, used to distribute IP routing information throughout a single Autonomous System (AS) in an IP network.
What type of LSAs are blocked in the totally stubby area?
TOTALLY STUBBY AREAS This area not only blocks the Type 5 (External) LSAs, but it also blocks Type 3 (Summary) LSAs too.
What is a totally stubby area?
A stub area that only allows routes internal to the area and restricts Type 3 LSAs from entering the stub area is often called a totally stubby area. External routes and destinations to other areas are no longer summarized or allowed into a totally stubby area.