OSPF Fundamentals in Enterprise Routing

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What type of routing protocol is OSPF?

Distance-vector protocol
Path-vector protocol
Hybrid protocol
Link-state protocol (correct)

What is the purpose of a Link State Advertisement (LSA) in OSPF?

To select the best routing protocol for the network
To calculate the shortest path to other routers
To distribute routing information throughout the network
To describe the state of a router's links to its immediate neighbours (correct)

How do routers in an OSPF network build their routing tables?

By randomly selecting a route to each destination
By exchanging routing information with their neighbours
By periodically querying a central routing database
By using an algorithm like Edsger Dijkstra's SPF (correct)

What is the advantage of OSPF over some other routing protocols?

It can use less bandwidth and converge more quickly (A) Signup and view all the answers

What happens when a link on a single OSPF router changes state?

A single link-state message is distributed throughout the network (A) Signup and view all the answers

What is the purpose of the Link State Database (LSDB) in OSPF?

To store all the link-state messages received by a router (D) Signup and view all the answers

What is the main disadvantage of link-state protocols?

They can be computationally intensive compared to distance-vector protocols. (D) Signup and view all the answers

What is the primary scaling overhead in link-state protocols?

Coping with the frequency of LSA updates as the size of a link-state area increases. (C) Signup and view all the answers

What is the role of area 0 in the OSPF network?

It acts as a central node and transmits link information of other areas. (D) Signup and view all the answers

What type of LSAs are supported by the standard area?

1, 2, 3, 4, and 5 LSAs. (A) Signup and view all the answers

How do distance-vector protocols compare to link-state protocols in terms of computation?

They require less computation. (B) Signup and view all the answers

What is the total number of OSPF areas mentioned in the text?

5 (A) Signup and view all the answers

What is the purpose of LSA Type 1 packets?

To describe its own interfaces and carry information about its neighbors to adjacent routers (D) Signup and view all the answers

What is the role of the Designated Router (DR) in generating LSA packets?

Generating LSA Type 2 packets (B) Signup and view all the answers

What type of LSA packets are generated by the ASBR to advertise external redistributed routes into the OSPF's AS?

LSA Type 5 (D) Signup and view all the answers

What is the total number of LSA types supported by OSPF?

11 (A) Signup and view all the answers

Where do LSA Type 1 packets remain?

Within the same area of origin (B) Signup and view all the answers

Which type of LSA packets are used by ABRs to advertise the ASBR route through their areas?

LSA Type 4 (C) Signup and view all the answers

What type of LSA packets are used by the ASBR to inform its neighbors within its networks?

LSA Type 1 (D) Signup and view all the answers

What is the purpose of LSA Type 2 packets?

To describe all routers connected to a segment directly (B) Signup and view all the answers

What is assumed about the reader's knowledge in this article?

The reader has a good understanding of basic OSPF theory and is comfortable with OSPF concepts (C) Signup and view all the answers

What is the purpose of LSA Type 6 packets?

To support multicast routing through OSPF (B) Signup and view all the answers

What type of entry would an external route/prefix be seen as in other OSPF routers routing tables?

O E1 or E2 (D) Signup and view all the answers

What is the status of Multicast OSPF (MOSPF) in terms of support by Cisco?

It is not supported by Cisco and is expected to be retired soon (B) Signup and view all the answers

What is the purpose of LSA Type 7 packets?

To mask LSA Type 5 packets and allow them to move through special areas (A) Signup and view all the answers

What is the main function of the ABR in relation to LSA Type 7 packets?

To translate LSA Type 7 packets back to LSA Type 5 packets (B) Signup and view all the answers

What is the purpose of LSA Type 8 packets in OSPFv2?

To transit BGP attributes through an OSPF network (D) Signup and view all the answers

What is the practical application of Opaque LSAs (LSA Type 9, 10 & 11)?

To extend the capabilities of OSPF in MPLS traffic engineering (A) Signup and view all the answers

What is the function of LSA Type 5 packets?

To convey BGP destinations through an OSPF network (D) Signup and view all the answers

What is the main difference between LSA Type 8 packets in OSPFv2 and OSPFv3?

OSPFv2 uses LSA Type 8 for external attributes, while OSPFv3 uses it for link local attributes (B) Signup and view all the answers