[H3CSE RS] H3CSE Routing Switching
Certification Review Guide
Question 1. **Which OSPF LSA type is used to advertise external routes into an OSPF
domain?**
A) Type 1
B) Type 2
C) Type 3
D) Type 5
Answer: D
Explanation: Type‑5 LSAs (AS‑External LSAs) are generated by ASBRs to distribute routes learned
from other routing domains into the OSPF area.
Question 2. **In OSPF, what state follows the “Init” state in the neighbor adjacency state
machine?**
A) Two‑Way
B) ExStart
C) Exchange
D) Loading
Answer: A
Explanation: After a router receives a Hello from a neighbor and verifies the router ID, it moves
from Init to Two‑Way, indicating bidirectional communication.
Question 3. **Which area type blocks the propagation of Type‑3 summary LSAs into the
area?**
A) Stub
B) Totally Stubby
C) NSSA
D) Backbone
, [H3CSE RS] H3CSE Routing Switching
Certification Review Guide
Answer: B
Explanation: A Totally Stubby area discards all external LSAs and also blocks inter‑area Type‑3
LSAs, reducing routing table size.
Question 4. **When configuring OSPF on a non‑broadcast multi‑access (NBMA) network, which
OSPF network type must be used?**
A) Broadcast
B) Point‑to‑Multipoint
C) Non‑Broadcast
D) Point‑to‑Point
Answer: C
Explanation: The NBMA network type tells OSPF to treat the medium as non‑broadcast,
requiring manual neighbor configuration.
Question 5. **In IS‑IS, what is the purpose of the Intermediate System to Intermediate System
Hello (IIH) PDU?**
A) To carry routing information
B) To establish adjacency between ISes
C) To request a password from a neighbor
D) To synchronize LSP databases
Answer: B
Explanation: IIH PDUs are exchanged to discover and form adjacencies between IS‑IS routers.
Question 6. **Which IS‑IS LSP flooding mechanism reduces unnecessary retransmissions by
acknowledging received LSPs?**
A) CSNP (Complete Sequence Number PDU)
, [H3CSE RS] H3CSE Routing Switching
Certification Review Guide
B) PSNP (Partial Sequence Number PDU)
C) IIH
D) Hello
Answer: B
Explanation: PSNP is used to request missing LSPs and confirm receipt, minimizing duplicate
transmissions.
Question 7. **In IS‑IS, what does the “Level‑2” domain correspond to?**
A) Intra‑area routing only
B) Backbone routing across the entire IS‑IS network
C) Routing inside a stub area
D) Routing between routers in a single LAN segment
Answer: B
Explanation: Level‑2 routers form the backbone of an IS‑IS network, analogous to OSPF’s Area 0,
and route between Level‑2 areas.
Question 8. **Which BGP attribute is evaluated first during path selection?**
A) Local Preference
B) AS‑Path length
C) Weight (Cisco‑specific)
D) MED
Answer: C
Explanation: Cisco’s proprietary Weight attribute is the highest‑priority attribute; it is considered
before any other BGP attribute.
Question 9. **What is the effect of the “next‑hop‑self” command on an iBGP session?**
, [H3CSE RS] H3CSE Routing Switching
Certification Review Guide
A) It changes the AS‑Path attribute to local AS.
B) It advertises the router’s own IP as the next hop for all routes.
C) It prevents route reflection.
D) It forces the router to become a route reflector.
Answer: B
Explanation: “next‑hop‑self” rewrites the next‑hop address to the local router’s IP, simplifying
iBGP topologies where the next hop may be unreachable.
Question 10. **Which BGP community value is used to indicate that a route should not be
advertised to any external peers?**
A) 65535:0
B) 0:65535
C) 65535:65535
D) 0:0
Answer: C
Explanation: The well‑known community 65535:65535 is “no‑export”, preventing the route
from being sent to eBGP peers.
Question 11. **In a BGP route reflector architecture, what is the purpose of a client‑to‑client
reflection rule?**
A) Clients can reflect routes to other clients.
B) Clients cannot reflect routes to other clients.
C) Only the reflector can reflect routes to clients.
D) Clients must use the same AS number.
Answer: B
Certification Review Guide
Question 1. **Which OSPF LSA type is used to advertise external routes into an OSPF
domain?**
A) Type 1
B) Type 2
C) Type 3
D) Type 5
Answer: D
Explanation: Type‑5 LSAs (AS‑External LSAs) are generated by ASBRs to distribute routes learned
from other routing domains into the OSPF area.
Question 2. **In OSPF, what state follows the “Init” state in the neighbor adjacency state
machine?**
A) Two‑Way
B) ExStart
C) Exchange
D) Loading
Answer: A
Explanation: After a router receives a Hello from a neighbor and verifies the router ID, it moves
from Init to Two‑Way, indicating bidirectional communication.
Question 3. **Which area type blocks the propagation of Type‑3 summary LSAs into the
area?**
A) Stub
B) Totally Stubby
C) NSSA
D) Backbone
, [H3CSE RS] H3CSE Routing Switching
Certification Review Guide
Answer: B
Explanation: A Totally Stubby area discards all external LSAs and also blocks inter‑area Type‑3
LSAs, reducing routing table size.
Question 4. **When configuring OSPF on a non‑broadcast multi‑access (NBMA) network, which
OSPF network type must be used?**
A) Broadcast
B) Point‑to‑Multipoint
C) Non‑Broadcast
D) Point‑to‑Point
Answer: C
Explanation: The NBMA network type tells OSPF to treat the medium as non‑broadcast,
requiring manual neighbor configuration.
Question 5. **In IS‑IS, what is the purpose of the Intermediate System to Intermediate System
Hello (IIH) PDU?**
A) To carry routing information
B) To establish adjacency between ISes
C) To request a password from a neighbor
D) To synchronize LSP databases
Answer: B
Explanation: IIH PDUs are exchanged to discover and form adjacencies between IS‑IS routers.
Question 6. **Which IS‑IS LSP flooding mechanism reduces unnecessary retransmissions by
acknowledging received LSPs?**
A) CSNP (Complete Sequence Number PDU)
, [H3CSE RS] H3CSE Routing Switching
Certification Review Guide
B) PSNP (Partial Sequence Number PDU)
C) IIH
D) Hello
Answer: B
Explanation: PSNP is used to request missing LSPs and confirm receipt, minimizing duplicate
transmissions.
Question 7. **In IS‑IS, what does the “Level‑2” domain correspond to?**
A) Intra‑area routing only
B) Backbone routing across the entire IS‑IS network
C) Routing inside a stub area
D) Routing between routers in a single LAN segment
Answer: B
Explanation: Level‑2 routers form the backbone of an IS‑IS network, analogous to OSPF’s Area 0,
and route between Level‑2 areas.
Question 8. **Which BGP attribute is evaluated first during path selection?**
A) Local Preference
B) AS‑Path length
C) Weight (Cisco‑specific)
D) MED
Answer: C
Explanation: Cisco’s proprietary Weight attribute is the highest‑priority attribute; it is considered
before any other BGP attribute.
Question 9. **What is the effect of the “next‑hop‑self” command on an iBGP session?**
, [H3CSE RS] H3CSE Routing Switching
Certification Review Guide
A) It changes the AS‑Path attribute to local AS.
B) It advertises the router’s own IP as the next hop for all routes.
C) It prevents route reflection.
D) It forces the router to become a route reflector.
Answer: B
Explanation: “next‑hop‑self” rewrites the next‑hop address to the local router’s IP, simplifying
iBGP topologies where the next hop may be unreachable.
Question 10. **Which BGP community value is used to indicate that a route should not be
advertised to any external peers?**
A) 65535:0
B) 0:65535
C) 65535:65535
D) 0:0
Answer: C
Explanation: The well‑known community 65535:65535 is “no‑export”, preventing the route
from being sent to eBGP peers.
Question 11. **In a BGP route reflector architecture, what is the purpose of a client‑to‑client
reflection rule?**
A) Clients can reflect routes to other clients.
B) Clients cannot reflect routes to other clients.
C) Only the reflector can reflect routes to clients.
D) Clients must use the same AS number.
Answer: B
