ACSP OSPF Routing Configuration 3 — Questions and Answers
Question 1: On an Aruba AOS-CX switch, which OSPF LSA type is generated by an ASBR to advertise external routes into the OSPF domain?
- Type 3 Summary LSA
- Type 4 ASBR Summary LSA
- Type 5 AS External LSA (Correct answer)
- Type 7 NSSA External LSA
Correct answer: Type 5 AS External LSA
Type 5 AS External LSAs are originated by ASBRs to flood external routing information throughout the OSPF domain (except stub areas).
Question 2: An Aruba switch in an NSSA area originates a Type 7 LSA for a redistributed external route. What converts it to a Type 5 LSA at the area border?
- The DR for the NSSA area
- The ABR connecting the NSSA to the backbone (Correct answer)
- The ASBR that originally redistributed the route
- The router with the highest router-id in the NSSA
Correct answer: The ABR connecting the NSSA to the backbone
The ABR at the NSSA boundary translates Type 7 LSAs to Type 5 LSAs so the external route information can propagate throughout the OSPF domain.
Question 3: What is the default OSPF hello interval on Aruba switch Ethernet interfaces?
- 5 seconds
- 10 seconds (Correct answer)
- 30 seconds
- 40 seconds
Correct answer: 10 seconds
Ethernet (broadcast) interfaces use a 10-second hello interval by default, with a dead interval of 40 seconds.
Question 4: An Aruba switch receives an OSPF DBD packet during neighbor exchange. What does the MS bit in the DBD indicate?
- The sending router is the master in the master/slave relationship (Correct answer)
- The router has more database pages to send
- The router is the designated router
- The DBD contains only summary LSA headers
Correct answer: The sending router is the master in the master/slave relationship
The MS (Master/Slave) bit in the DBD packet indicates which router is the master, controlling the DBD sequence number exchange during OSPF database synchronization.
Question 5: Which OSPF neighbor state indicates that the two Aruba switches have fully synchronized their link-state databases?
- EXCHANGE
- LOADING
- FULL (Correct answer)
- 2-WAY
Correct answer: FULL
The FULL state means both routers have identical LSDBs and the adjacency is complete; this is the desired end state for OSPF neighbors.
Question 6: When redistributing static routes into OSPF on an Aruba AOS-CX switch, which command is used and what default metric type is applied?
- redistribute static, Type 1 (E1) by default
- redistribute static, Type 2 (E2) by default (Correct answer)
- import static, Type 1 (E1) by default
- inject static, Type 2 (E2) by default
Correct answer: redistribute static, Type 2 (E2) by default
The 'redistribute static' command under router ospf injects static routes as OSPF external routes with Type 2 (E2) metric by default.
Question 7: On an Aruba switch, what is the purpose of OSPF route summarization configured on an ABR?
- To reduce the number of Type 3 LSAs sent from the ABR into other areas (Correct answer)
- To prevent Type 5 external LSAs from entering stub areas
- To combine multiple Type 1 LSAs within an area into one
- To reduce the OSPF hello packet size
Correct answer: To reduce the number of Type 3 LSAs sent from the ABR into other areas
ABR summarization aggregates multiple specific Type 3 inter-area LSAs into a single summary LSA, reducing LSDB size and SPF computation in other areas.
ACSP OSPF Routing Configuration 3
On an Aruba AOS-CX switch, which OSPF LSA type is generated by an ASBR to advertise external routes into the OSPF domain?