CS6250 Computer Networks Exam 1 |
Questions and Verified Answers |
Rated A+ | Latest 2025/2026 Guide
1: Select the words that can be used to describe the distance vector
algorithm:
Multiple choice:
A. Distributed
B. Centralized
C. Iterative
D. Asynchronous
E. Synchronous
F. Non-terminating
- Correct Answer - A, C, D
2: Determine which of the following can cause the count-to-infinity
problem.
Select one:
A. Poison reversing
B. Routing Loops
C. Hot potato routing
D. Dropped packets
- Correct Answer - B
1: What type of algorithm is Dijkstra's algorithm?
Select one:
,A. Decentralized
B. Centralized (Global)
- Correct Answer - B
Rationale:
Link-state algorithm uses Dijkstra's algorithm under the hood. The
algorithm is centralized (global) because the nodes all know the link
costs and topology of the network.
2: The Bellman Ford equation is used by the ___ algorithm.
Select one:
A. Link-state
B. Distance Vector
- Correct Answer - B
Rationale:
Distance vector algorithm uses Bellman Ford algorithm under the hood.
The algorithm is decentralized because all the nodes don't know the link
costs of all the nodes and the full topology.
3: The Routing Information Protocol (RIP) is an example of ___.
Multiple choice:
A. a link-state algorithm
B. a distance vector algorithm
C. poison reverse
D. an interdomain routing algorithm
E. an intradomain routing algorithm
- Correct Answer - B, E
Rationale:
,Routing Information Protocol (RIP) one of two IGPs (Interior Gateway
Protocols -- intradomain routing protocols) which are used to determine
the shortest path within an AS (intradomain routing). RIP uses Distance
Vector algorithm (which uses Bellman Ford algorithm under the hood).
Likewise, Open Shortest Path First (OSPF) protocol is the other IGP.
OSPF uses Link-state algorithm (which uses Dijkstra's algorithm) under
the hood.
PQ3-5-1: There may be multiple egress points from an AS (i.e.
Administrative domain i.e. Autonomous System) to an external
destination.
True or false?
- Correct Answer - True
Rationale:
There can be both one or many egress (exit) points and one or many
ingress (entry) points in a single AS.
PQ3-5-2: Hot potato routing always selects the egress point that is
geographically closest to the ingress point.
True or false?
- Correct Answer - False
Rationale:
Hot potato routing is a technique/practice of choosing a path within the
network (single AS) by choosing the "closest" egress point based on the
lowest intradomain path cost (Interior Gateway Protocol/IGP cost)
, Thus, although one point might be "closer" geographically -- if it has a
higher accumulative path cost than another path, the path with the lower
cost is picked.
LQ3-1: "Routing" and "Forwarding" are interchangeable terms.
True or false?
- Correct Answer - False
Rationale:
Routing = routing on Layer 3 (Network Layer) using IP protocol using
routers to determine the "best" path in an AS.
Forwarding = a packet reaching an input link of a router/switch, input
link interface checks the Forwarding Table (FIB i.e. Forwarding
Information Base) to see which output link to, then switch fabric sends it
to the correct output link
LQ3-2: Consider a source and destination host. Before packets leave
the source host, the host needs to define the path over which the
packets will travel to reach the destination host.
True or false?
- Correct Answer - False
Rationale:
The path is determined by the Network Layer.
Each AS decides which IGP (Interior Gateway Protocol) routing
algorithm to use (RIP vs OSPF). This generates Routing Tables (to
determine the smallest cost path to the destination host and the next-
hop router) and Forwarding Tables (to know which output link to send a
Questions and Verified Answers |
Rated A+ | Latest 2025/2026 Guide
1: Select the words that can be used to describe the distance vector
algorithm:
Multiple choice:
A. Distributed
B. Centralized
C. Iterative
D. Asynchronous
E. Synchronous
F. Non-terminating
- Correct Answer - A, C, D
2: Determine which of the following can cause the count-to-infinity
problem.
Select one:
A. Poison reversing
B. Routing Loops
C. Hot potato routing
D. Dropped packets
- Correct Answer - B
1: What type of algorithm is Dijkstra's algorithm?
Select one:
,A. Decentralized
B. Centralized (Global)
- Correct Answer - B
Rationale:
Link-state algorithm uses Dijkstra's algorithm under the hood. The
algorithm is centralized (global) because the nodes all know the link
costs and topology of the network.
2: The Bellman Ford equation is used by the ___ algorithm.
Select one:
A. Link-state
B. Distance Vector
- Correct Answer - B
Rationale:
Distance vector algorithm uses Bellman Ford algorithm under the hood.
The algorithm is decentralized because all the nodes don't know the link
costs of all the nodes and the full topology.
3: The Routing Information Protocol (RIP) is an example of ___.
Multiple choice:
A. a link-state algorithm
B. a distance vector algorithm
C. poison reverse
D. an interdomain routing algorithm
E. an intradomain routing algorithm
- Correct Answer - B, E
Rationale:
,Routing Information Protocol (RIP) one of two IGPs (Interior Gateway
Protocols -- intradomain routing protocols) which are used to determine
the shortest path within an AS (intradomain routing). RIP uses Distance
Vector algorithm (which uses Bellman Ford algorithm under the hood).
Likewise, Open Shortest Path First (OSPF) protocol is the other IGP.
OSPF uses Link-state algorithm (which uses Dijkstra's algorithm) under
the hood.
PQ3-5-1: There may be multiple egress points from an AS (i.e.
Administrative domain i.e. Autonomous System) to an external
destination.
True or false?
- Correct Answer - True
Rationale:
There can be both one or many egress (exit) points and one or many
ingress (entry) points in a single AS.
PQ3-5-2: Hot potato routing always selects the egress point that is
geographically closest to the ingress point.
True or false?
- Correct Answer - False
Rationale:
Hot potato routing is a technique/practice of choosing a path within the
network (single AS) by choosing the "closest" egress point based on the
lowest intradomain path cost (Interior Gateway Protocol/IGP cost)
, Thus, although one point might be "closer" geographically -- if it has a
higher accumulative path cost than another path, the path with the lower
cost is picked.
LQ3-1: "Routing" and "Forwarding" are interchangeable terms.
True or false?
- Correct Answer - False
Rationale:
Routing = routing on Layer 3 (Network Layer) using IP protocol using
routers to determine the "best" path in an AS.
Forwarding = a packet reaching an input link of a router/switch, input
link interface checks the Forwarding Table (FIB i.e. Forwarding
Information Base) to see which output link to, then switch fabric sends it
to the correct output link
LQ3-2: Consider a source and destination host. Before packets leave
the source host, the host needs to define the path over which the
packets will travel to reach the destination host.
True or false?
- Correct Answer - False
Rationale:
The path is determined by the Network Layer.
Each AS decides which IGP (Interior Gateway Protocol) routing
algorithm to use (RIP vs OSPF). This generates Routing Tables (to
determine the smallest cost path to the destination host and the next-
hop router) and Forwarding Tables (to know which output link to send a
