DevNet Associate (DEVASC) v1.0Cisco Platforms and DevelopmentMedium
A network engineer is tasked with programmatically configuring Quality of Service (QoS) policies on a fleet of Cisco IOS XE routers. The engineer needs to define traffic classes, allocate bandwidth, and prioritize specific application flows. Which programmability feature on Cisco IOS XE would be most suitable for this task, offering a declarative approach to configuration management?
- ASNMP SET operations
- BCLI scripting with Expect
- CREST API calls to the embedded web server
- DNETCONF with YANG data models
Show answer & explanationAnswer & explanation
Correct answer: D. NETCONF with YANG data models
NETCONF with YANG data models provides a standardized, programmatic, and declarative way to configure network devices, including complex QoS policies on Cisco IOS XE. This approach ensures consistent and verifiable configurations.
Why the other options are wrong
- A. SNMP SET operations are generally used for monitoring and basic configuration, not for defining complex, declarative QoS policies.
- B. CLI scripting with Expect is imperative and prone to errors due to text parsing, making it less suitable for complex, declarative configurations.
- C. While some IOS XE devices have REST APIs, NETCONF with YANG is the standard and most robust declarative approach for configuration management.
NETCONF with YANG
NETCONF is a network management protocol that provides mechanisms to install, manipulate, and delete device configurations. YANG is a data modeling language used to define the structure and constraints of configuration and state data.
- Uses XML encoding for data exchange.
- Provides transactional configuration capabilities.
- YANG models define hierarchical data structures.
Memory trick: YANG models give NETCONF the blueprint for the network.