Quick Answer: What Action Does An ABR Take When It Receives A Type 1 LSA?

Which two LSA types are generated exclusively by ABRs?

Let me summarize the LSA types for you:Type 1 – Router LSA: The Router LSA is generated by each router for each area it is located.

Type 2 – Network LSA: Network LSAs are generated by the DR.

Type 3 – Summary LSA: The summary LSA is created by the ABR and flooded into other areas.More items….

Who generates Type 4 LSA?

ABR R1There is only one type 4 LSA present in the R4 OSPF database. The type 4 LSA was generated by ABR R1 and describing the ASBR with the router ID 3.3. 3.3.

How do I find my OSPF LSA?

To display general information about Open Shortest Path First (OSPF) routing instances, use the show ip ospf command. Use the show ip ospf command to display information about one or more OSPF instances.

What contains LSA?

The LSAs (Link-State Advertisements) are used by routers running OSPF to exchange topology information. An LSA contains routing and topology information that describe a part of an OSPF network. Routers exchange LSAs and learn the complete topology of the network until all routers have the exact same topology database.

What is DR and BDR in OSPF?

OSPF uses a DR (Designated Router) and BDR (Backup Designated Router) on each multi-access network. … You change the priority if you like by using the ip ospf priority command: The default priority is 1. A priority of 0 means you will never be elected as DR or BDR.

What are the different LSA types of OSPF?

LSA Type 1: Router LSA.LSA Type 2: Network LSA.LSA Type 3: Summary LSA.LSA Type 4: Summary ASBR LSA.LSA Type 5: Autonomous system external LSA.LSA Type 6: Multicast OSPF LSA.LSA Type 7: Not-so-stubby area LSA.LSA Type 8: External attribute LSA for BGP.

What is a Type 3 LSA?

Type 3 LSAs are generated by ABR. … They represent networks from an area and are sent to the rest of the areas in OSPF domain. Type 1 LSAs don’t cross area boundary, so Area Border Router (ABR) uses type 3 LSA to inform other areas about networks learned in its area.

What is a Type 5 LSA?

OSPF creates a type 5 LSA for a subnet that is injected into OSPF from an external source. … To inject the route, the autonomous System Border Router (ASBR), which is by definition a router that connects to a non-OSPF routing domain, uses the redistribute command.

What is Type 7 LSA OSPF?

Type 7 LSA The NSSA ASBR redistributes routes from different routing protocol(s) into OSPF, and vice versa. This router sets the E-bit in Router LSA flag. The ASBR originates a separate Type 7 LSA for each external route. Type 7 LSAs are only flooded within the originating NSSA.

What information is advertised in a type 4 LSA?

An OSPF type 4 summary LSA is generated by an ABR only when an ASBR exists within an area. A type 4 LSA identifies the ASBR and provides a route to it so the routing table will have an entry for traffic that is destined for the external autonomous network.

LSA Type 8: Link LSA. Link Local scope: LSA is only flooded on the local link and is further used for the LINK-LSA. LSA Type 9: Intra-Area LSA. Area Scope: LSA is only flooded throughout a single OSPF area.

What is a Type 2 LSA?

Type 2 – Network LSA – the designated router (DR) on a broadcast segment (e.g. Ethernet) lists which routers are joined together by the segment. Type 2 LSAs are flooded across their own area only. The link-state ID of the type 2 LSA is the IP interface address of the DR.

How many OSPF LSA types?

6 Types6 Types of OSPF LSA.

Why do we need areas in OSPF?

In OSPF, a single autonomous system (AS) can be divided into smaller groups called areas. This reduces the number of link-state advertisements (LSAs) and other OSPF overhead traffic sent on the network, and it reduces the size of the topology database that each router must maintain.

Virtual Link Configuration At least one end of a virtual link must be terminated on a backbone (area 0) router. Virtual links are created under the OSPF process configuration by referencing the peer router’s RID, not an IP address. A new adjacency is created over the virtual link interface, called OSPFv3_VL1.

What is stubby area in OSPF?

A stub area is an area in which you do not allow advertisements of external routes, which thus reduces the size of the database even more. Instead, a default summary route (0.0. … Stub areas are shielded from external routes but receive information about networks that belong to other areas of the same OSPF domain.

What are LSA types?

LSA Types – Quick OverviewLSA Type 1: OSPF Router LSA.LSA Type 2: OSPF Network LSA.LSA Type 3: OSPF Summary LSA.LSA Type 4: OSPF ASBR Summary LSA.LSA Type 5: OSPF ASBR External LSA.LSA Type 6: OSPF Group Membership LSA.LSA Type 7: OSPF Not So Stubby Area (NSSA) External LSA.More items…

Why is type 4 LSA required?

So, a type-4 asbr-summary LSA is needed to help make the ASBR reachable and, by extension make the associated type-5 prefix valid. The type-4 acts like a glue record, and uses the ABRs well known RID as a care-of address for the ASBR and it’s advertised prefixes.

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

The difference between the two metrics is how OSPF calculates the cost of the route. … This means that Type 1 external metrics include the external cost to the destination as well as the cost (metric) to reach the AS boundary router. Type 2 external metrics are greater than the cost of any path internal to the AS.

Which type of OSPF router will generate Type 3 LSAs?

Area Border RoutersWhich type of OSPF router will generate type 3 LSAs? Type 3 OSPF LSAs are generated by Area Border Routers (ABRs) to advertise networks between OSPF areas.

Is is Intermediate System to Intermediate System?

The Intermediate System-to-Intermediate System (IS-IS) routing protocol is an Interior Gateway Protocol (IGP) standardized by the Internet Engineering Task Force (IETF) and commonly used in large Service Provider networks.