CCN Final Exam Study Questions &
Answers
What are the major differences between virtual circuit and datagram networks? -
ANSWERSVirtual Circuits have a predetermined destination
Datagrams have to calculate the destination at each hop
What are the major differences between routing and forwarding? - ANSWERSForwarding does
not require route calculation the port is predetermined
Routing requires route calculation and the routers need to exchange their information
What are the objectives of routing protocols? - ANSWERSA routing protocol sets up a routing
table in routers switch controllers
How does IP find the best next hop? - ANSWERSA node makes a local choice depending on
global topology
How does IP avoid congested routes? (5) - ANSWERS1. Network provisioning
2. Traffic aware routing
3. Admission control
4. Traffic shaping
5. Traffic throttling
How does IP maintain load balancing? - ANSWERSTraffic management
How does IP avoid loops? - ANSWERSMinimize the number and frequency of messages
, How does Link State routing work? - ANSWERS1 Finds out who its neighbors are and get their
network addresses
2 Calculates the cost (time) for getting a packet to a neighbor
3 Constructs a LinK State Packet (LSP) telling all it has just learned
4 Sends LSP to all other routers (not just neighbors)
5 Runs Dijkstras algorithm locally
How does Distance Vector routing work? - ANSWERSEach router sends a vector of distance to its
neighbors
Global information to local neighbors
How does IP handle mobility? - ANSWERSHost mobility + Wireless + Router Mobility
What is the role of a leaky bucket in IP networks? What problem(s) it solves? - ANSWERSLeaky
bucket helps with rate an jitter control
Regulates bursty traffic
Short bursts are tolerated and longbursts may overflow into the bucket
What is the role of a token bucket in IP networks? What problem(s) it solves? - ANSWERSSolves
rate control
Tokens are added at a constant rate
An arriving packet facing an empty bucket cannot beforwarded
What do we mean by network provisioning ? - ANSWERSThrow resources at the problem
May solve the problem but not for very long
Answers
What are the major differences between virtual circuit and datagram networks? -
ANSWERSVirtual Circuits have a predetermined destination
Datagrams have to calculate the destination at each hop
What are the major differences between routing and forwarding? - ANSWERSForwarding does
not require route calculation the port is predetermined
Routing requires route calculation and the routers need to exchange their information
What are the objectives of routing protocols? - ANSWERSA routing protocol sets up a routing
table in routers switch controllers
How does IP find the best next hop? - ANSWERSA node makes a local choice depending on
global topology
How does IP avoid congested routes? (5) - ANSWERS1. Network provisioning
2. Traffic aware routing
3. Admission control
4. Traffic shaping
5. Traffic throttling
How does IP maintain load balancing? - ANSWERSTraffic management
How does IP avoid loops? - ANSWERSMinimize the number and frequency of messages
, How does Link State routing work? - ANSWERS1 Finds out who its neighbors are and get their
network addresses
2 Calculates the cost (time) for getting a packet to a neighbor
3 Constructs a LinK State Packet (LSP) telling all it has just learned
4 Sends LSP to all other routers (not just neighbors)
5 Runs Dijkstras algorithm locally
How does Distance Vector routing work? - ANSWERSEach router sends a vector of distance to its
neighbors
Global information to local neighbors
How does IP handle mobility? - ANSWERSHost mobility + Wireless + Router Mobility
What is the role of a leaky bucket in IP networks? What problem(s) it solves? - ANSWERSLeaky
bucket helps with rate an jitter control
Regulates bursty traffic
Short bursts are tolerated and longbursts may overflow into the bucket
What is the role of a token bucket in IP networks? What problem(s) it solves? - ANSWERSSolves
rate control
Tokens are added at a constant rate
An arriving packet facing an empty bucket cannot beforwarded
What do we mean by network provisioning ? - ANSWERSThrow resources at the problem
May solve the problem but not for very long
