1) OSPF Authentication Happens in Which State?
A: TWO Way state
2) What are the must match parameters to become neighbors in OSPF?
A: 1) HELLO TIME and DEAD Interval
2) Unique Router-ID
3) Area ID
4) Area Type
5) Subnet Mask
6) Authentication
3) What is the difference between Adjacency and Neighbor ship in OSPF?
--> Adjacent Routers are the routers that exchanged hello messages, LSA and have synchronized LSDB.
---> Neighbor Routers are the routers that exchanged only hello messages.
Ex: DR-- BDR/DROTHER ( Adjacent Routers)
DROTHER-- DROTHER ( Neighbor Routers)
4) How many states are present in OSPF?
1) DOWN
2) INIT
3) 2-WAY
4) EXSTART
5) EXCHANGE
6) LOADING
7) FULL
8) ATTEMPT ( only in NBMA networks)
5) IN DR/BDR election which router is elected first?
--> BDR is elected first then DR
6) TWO way state is a problem in OSPF?
A: No it is normal in Broadcast Network
7) If there are routers present in the area, which router does the conversion of LSA7 to LSA 5 in OSPF ?
A: ABR with lowest router-id
8) can we stop some specific routes entering into NSSA in OSPF?
A: Yes by giving no-advertise command
9) LSA 3 and LSA 4 are generated by which router in OSPF?
A: i) LSA 3 is generated by ABR of each Area.
ii) LSA 4 is generated by ABR of each Area where ASBR is present.
10) When to use Stub and Not So Stubby Area in OSPF?
A: When you don’t want external LSA into the area.
11) What is the different type of route summarization available in OSPF?
A: Only Manual Summarization
12) What is the difference between OSPF and IS-IS and which one is preferred?
A:
1) IS-IS does not support Virtual links whereas OSPF supports the virtual link concept.
2) IS-IS is more flexible compared to OSPF.
3)IS-IS Supports only simple authentication whereas OSPF supports simple authentication ( Clear Text) as well as MD-5 Authentication.
4) Both are classless and link-state routing protocols.
5) OSPF routers form neighbor relationships only if hello and hold down timers match whereas in IS-IS hello interval and hold down timer need not match to form a neighbor relationship.
13) Is the OSPF link state or distance vector or path-vector protocol?
Ans: Link State Routing Protocol
14) How many network types available in OSPF?
Ans:
1) Point to Point network
2) BMA
3) NBMA
4) point to multipoint
5) point to multipoint non-broadcast
15) Different types of Link State Advertisements aka LSA?
Ans:
1) Router LSA
2) Network LSA
3) Summary LSA
4) Summary ASBR LSA
5) Autonomous system external LSA
6) Multicast OSPF LSA
7) Not-so-stubby area LSA
8) External attribute LSA for BGP
16) Difference between EIGRP and OSPF protocol?
17) One side MTU is 1500 and another side MTU is 1600. Does it affect the neighbor relationship in OSPF?
A: TWO Way state
2) What are the must match parameters to become neighbors in OSPF?
A: 1) HELLO TIME and DEAD Interval
2) Unique Router-ID
3) Area ID
4) Area Type
5) Subnet Mask
6) Authentication
3) What is the difference between Adjacency and Neighbor ship in OSPF?
--> Adjacent Routers are the routers that exchanged hello messages, LSA and have synchronized LSDB.
---> Neighbor Routers are the routers that exchanged only hello messages.
Ex: DR-- BDR/DROTHER ( Adjacent Routers)
DROTHER-- DROTHER ( Neighbor Routers)
4) How many states are present in OSPF?
1) DOWN
2) INIT
3) 2-WAY
4) EXSTART
5) EXCHANGE
6) LOADING
7) FULL
8) ATTEMPT ( only in NBMA networks)
5) IN DR/BDR election which router is elected first?
--> BDR is elected first then DR
6) TWO way state is a problem in OSPF?
A: No it is normal in Broadcast Network
7) If there are routers present in the area, which router does the conversion of LSA7 to LSA 5 in OSPF ?
A: ABR with lowest router-id
8) can we stop some specific routes entering into NSSA in OSPF?
A: Yes by giving no-advertise command
9) LSA 3 and LSA 4 are generated by which router in OSPF?
A: i) LSA 3 is generated by ABR of each Area.
ii) LSA 4 is generated by ABR of each Area where ASBR is present.
10) When to use Stub and Not So Stubby Area in OSPF?
A: When you don’t want external LSA into the area.
11) What is the different type of route summarization available in OSPF?
A: Only Manual Summarization
12) What is the difference between OSPF and IS-IS and which one is preferred?
A:
1) IS-IS does not support Virtual links whereas OSPF supports the virtual link concept.
2) IS-IS is more flexible compared to OSPF.
3)IS-IS Supports only simple authentication whereas OSPF supports simple authentication ( Clear Text) as well as MD-5 Authentication.
4) Both are classless and link-state routing protocols.
5) OSPF routers form neighbor relationships only if hello and hold down timers match whereas in IS-IS hello interval and hold down timer need not match to form a neighbor relationship.
13) Is the OSPF link state or distance vector or path-vector protocol?
Ans: Link State Routing Protocol
14) How many network types available in OSPF?
Ans:
1) Point to Point network
2) BMA
3) NBMA
4) point to multipoint
5) point to multipoint non-broadcast
15) Different types of Link State Advertisements aka LSA?
Ans:
1) Router LSA
2) Network LSA
3) Summary LSA
4) Summary ASBR LSA
5) Autonomous system external LSA
6) Multicast OSPF LSA
7) Not-so-stubby area LSA
8) External attribute LSA for BGP
16) Difference between EIGRP and OSPF protocol?
EIGRP OSPF
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1) Advanced Distance Vector 1) Link State Routing Protocol
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2) AD: 90 2)AD:110
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3) Supports Manual and Auto summary 3) Supports Manual summary only
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4) Supports Equal and Unequal cost load balancing 4) Supports Equal only
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5) Support only MD-5 authentication 5) Clear Text and MD-5 authentication
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6) No support of areas 6) Supports areas
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7) Multicast address 224.0.0.10 7)224.0.0.5 & 224.0.0.6
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8) Hop Count : 255 8) Hop Count: unlimited
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9) Metric : Composite Metric(bandwidth+delay) 9) Metric=cost(bandwidth)
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17) One side MTU is 1500 and another side MTU is 1600. Does it affect the neighbor relationship in OSPF?
Ans: Neighbors will be stuck in the EXSTART state always in OSPF.
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