Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
What is a northbound API in a controller-based network architecture?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
An interface used by the controller to program forwarding tables on switches
Programming network devices is typically a southbound function.
B
Best answer
An interface used by applications to communicate with the controller
Correct. Northbound means application-to-controller communication.
C
Distractor review
A dedicated out-of-band management port on the controller
A physical management port is unrelated to the northbound/southbound architectural distinction.
D
Distractor review
A wireless uplink between access points and the controller
Wireless uplinks do not define API direction in controller-based networking.
Common exam trap
Common exam trap: answer the scenario, not the keyword
Confusing northbound and southbound APIs is a common pitfall. Northbound APIs enable applications to communicate with the controller, while southbound APIs allow the controller to program network devices like switches and routers. Selecting an option that describes device programming or physical ports misses the architectural directionality of these APIs.
Technical deep dive
How to think about this question
In controller-based network architectures, such as those used in Software Defined Networking (SDN), APIs are categorized by their direction relative to the controller. Northbound APIs expose the controller's capabilities to external applications, enabling programmability, automation, and integration with network management tools. These APIs typically use RESTful interfaces or other protocols to allow applications to request network state information, push policies, or trigger workflows. Conversely, southbound APIs are used by the controller to communicate with network devices like switches and routers, programming forwarding tables, configuring VLANs, or managing routing protocols. Examples of southbound protocols include OpenFlow, NETCONF, and SNMP. Understanding this separation is crucial for implementing automation and programmability in Cisco networks, as it clarifies how controllers interact with both applications and devices to achieve centralized control and dynamic network behavior.
KKey Concepts to Remember
- Northbound API
- Controller-based network architecture
- Southbound API
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
Northbound API
What is the correct answer to this question?
The correct answer is: An interface used by applications to communicate with the controller — Northbound APIs allow external applications, dashboards, and automation tools to interact with the controller. Southbound APIs are used by the controller to communicate with the network devices it manages.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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