Routing

Question 1

What is the multicast address used by OSPFv3?

Answer 1

FF02::5

Question 2

Which version of OSPF supports Bidirectional Forwarding Detection (BFD)?

Answer 2

OSPFv2

Question 3

What is a Type 1 LSA known as?

Answer 3

Router LSA

Question 4

What is a Type 2 LSA known as?

Answer 4

Network LSA

Question 5

What is a Type 3 LSA known as in OSPFv2 and OSFPv3?

Answer 5

OSPFv2: Network Summary LSA
OSPFv3: Inter-Area Prefix LSA

Type 3 LSA are advertised by Area Border Routers (ABR). The advertisements are subnets that are originated in other areas.

Question 6

What is a Type 4 LSA known as in OSPFv2 and OSFPv3?

Answer 6

OSPFv2: ASBR Summary LSA
OSPFv3: Inter-Area Router LSA

Type 4 – Summary ASBR LSA: Other routers need to know where to find the ASBR. This is why the ABR will generate a summary ASBR LSA which will include the router ID of the ASBR in the link-state ID field.

Question 7

What is a Type 5 LSA known as in OSPFv2 and OSFPv3?

Answer 7

OSPFv2: AS External LSA
OSPFv3: AS External LSA

Question 8

What is a Type 7 LSA known as in OSPFv2 and OSFPv3?

Answer 8

OSPFv2: NSSA External LSA
OSPFv3: NSSA External LSA

Question 9

Which OSPFv3 LSA advertises only on the local link and only IPv6 addresses on that local link?

Answer 9

Type 8: Link LSA

Question 10

Which OSPFv3 LSA advertises IPv6 Prefixes into the local area?

Answer 10

Type 9: Intra-Area Prefix LSA

Question 11

Which OSPFv3 LSA is sent by a restarting router to allow for a graceful restart of OSPF?

Answer 11

Type 10: Grace LSA

Question 12

What is the OSPF LSA Group Pacing feature and why is it used?

Answer 12

This feature groups LSAs with similar link-state refresh times to allow OSPF to pack multiple LSAs into an OSPF update message. This feature reduces CPU and buffer usage.

Question 13

Which OSPF LSA type is not sent into a stub area?

Answer 13

Type 5: AS External LSA are not sent into stub areas.

Question 14

How is an OSPF NSSA different from a stub area? Which type of LSAs are accepted into NSSA areas?

Answer 14

NSSA include an ASBR, and accept AS External LSAs.

Type 7 AS External LSA’s are converted to Type 5 NSSA External LSAs by the ASBR when sent into an NSSA.

Question 15

Which OSPF LSA Type is only generated by a Designated Router (DR)?

Answer 15

Type 2: Network LSAs

Question 16

Which OSPF network types will elect a DR/BDR?

Answer 16

Broadcast and NBMA network types will elect a DR/BDR

Question 17

What multicast address is used by all OSPFv2 Routers and DR/BDRs?

Answer 17

All OSPF Routers: 224.0.0.5

All DR/BDR Routers: 224.0.0.6

Question 18

What is the default OSPF hello interval?

Answer 18

10 Seconds

Question 19

What is the default OSPF dead interval?

Answer 19

40 Seconds, 4 times the hello interval

Question 20

What port number is used by BGP?

Answer 20

TCP port 179

Question 21

What is the BGP path selection process?

Answer 21

We Love Oranges AS Oranges Means Pure Refreshment.

Weight (Highest, Cisco Proprietary) 
Local Preference (Highest)
Originate (Local, Network Command, injected routes)
AS Path (Shortest)
Origin Code (IGP > EGP > Incomplete)
MED (Lowest)
Paths ((External > Internal, Prefer EBGP over IBGP)
RID (Lowest Router ID)

Question 22

What is the default BGP keepalive interval?

Answer 22

60 Seconds

Question 23

What is the default BGP Hold Timer?

Answer 23

180 Seconds (3 Times keepalive)

Question 24

What is the default BFD minimum receive interval?

Answer 24

50ms

Question 25

What is the default BFD minimum transmit interval?

Answer 25

50ms

Question 26

What is the range of IPv4 Multicast addresses?

Answer 26

224.0.0.0 - 239.255.255.255

Question 27

What is the IPv6 multicast address?

Answer 27

0xFF