CS 6250 Computer Networks Exam 2 |
Practice Questions and Correct
Answers | Graded A+
What are three information sources provided by OpenFlow protocol?
- Correct Answer - 1. Event-based messages that are sent by forward
devices to controller when there is a link or port change
2. flow statistics are generated by forwarding devices and collected by
controller
3. Packet messages are sent by forwarding devices to controller when
they do not know what to do with a new incoming flow
What are the core functions of the SDN controller?
- Correct Answer - Network service functions such as topology, statistics,
notifications, device management, shortest path forwarding and security
mechanisms
What are the differences between centralized and distributed
architectures of SDN controllers?
- Correct Answer - Single entity manages all devices in the network
In the distributed version, its a centralized cluster of nodes or physical
set of elements
,When would you want a distributed controller over a centralized one? -
Correct Answer - If you want to scale your network and want better fault
tolerance
Describe the purpose of each component of ONOS in a SDN control
platform - Correct Answer - Serves as the master openflow controller for
a group of switches
??? weird question
How does ONOS achieve fault tolerance? - Correct Answer - ONOS
redistributes the work of a failed instance to other remaining instances.
Each switch in the network is connected to multiple ONOS instances
with one being a master
What is P4? - Correct Answer - High level programming to configure
switches which works in conjunction with SDN control protocols
What are the primary goals of P4? - Correct Answer - Reconfigurability -
The way parsing and processing of packets takes place in the switches
should be modified by the controller
Protocol Independence - To enable the switches to be independnt of any
particular protol, the contorller defines a packet parser and set of tables
, Target Independence - packet processing programs shuold be
programmed independent of underlying target devices
What are the two main operations of P4 Forwarding Model? - Correct
Answer - Configure - These sets of operations are used to program the
parser. They specify the header fields to be processed in each
match+action stage
Populate: The entries in the match + action tables specified during
configuration may be altered using the populate operations
What are the applications of SDN? - Correct Answer - 1. Traffic
Engineering -
2. Mobility and wireless
3. Measurement and Monitoring - Opensketch
4. Security and Dependability- Ddos protection
5. Data Center Networking - LIME, Flowdiff
What BGP limitations can be addressed by using SDN? - Correct
Answer - 1. Routing only on destination IP prefix
2. Networks have little control over end-to-end paths
Practice Questions and Correct
Answers | Graded A+
What are three information sources provided by OpenFlow protocol?
- Correct Answer - 1. Event-based messages that are sent by forward
devices to controller when there is a link or port change
2. flow statistics are generated by forwarding devices and collected by
controller
3. Packet messages are sent by forwarding devices to controller when
they do not know what to do with a new incoming flow
What are the core functions of the SDN controller?
- Correct Answer - Network service functions such as topology, statistics,
notifications, device management, shortest path forwarding and security
mechanisms
What are the differences between centralized and distributed
architectures of SDN controllers?
- Correct Answer - Single entity manages all devices in the network
In the distributed version, its a centralized cluster of nodes or physical
set of elements
,When would you want a distributed controller over a centralized one? -
Correct Answer - If you want to scale your network and want better fault
tolerance
Describe the purpose of each component of ONOS in a SDN control
platform - Correct Answer - Serves as the master openflow controller for
a group of switches
??? weird question
How does ONOS achieve fault tolerance? - Correct Answer - ONOS
redistributes the work of a failed instance to other remaining instances.
Each switch in the network is connected to multiple ONOS instances
with one being a master
What is P4? - Correct Answer - High level programming to configure
switches which works in conjunction with SDN control protocols
What are the primary goals of P4? - Correct Answer - Reconfigurability -
The way parsing and processing of packets takes place in the switches
should be modified by the controller
Protocol Independence - To enable the switches to be independnt of any
particular protol, the contorller defines a packet parser and set of tables
, Target Independence - packet processing programs shuold be
programmed independent of underlying target devices
What are the two main operations of P4 Forwarding Model? - Correct
Answer - Configure - These sets of operations are used to program the
parser. They specify the header fields to be processed in each
match+action stage
Populate: The entries in the match + action tables specified during
configuration may be altered using the populate operations
What are the applications of SDN? - Correct Answer - 1. Traffic
Engineering -
2. Mobility and wireless
3. Measurement and Monitoring - Opensketch
4. Security and Dependability- Ddos protection
5. Data Center Networking - LIME, Flowdiff
What BGP limitations can be addressed by using SDN? - Correct
Answer - 1. Routing only on destination IP prefix
2. Networks have little control over end-to-end paths
