Introduction to Network Automation - REST API, RESTCONF, NETCONF, gNMI, and SNMP

What Is RESTCONF?

RESTCONF is a network automation protocol based on REST principles.

It was specifically designed for managing network devices.

RESTCONF uses:

• HTTP/HTTPS
• JSON or XML

• YANG data models

   

How Does RESTCONF Work?

RESTCONF allows you to:

• retrieve configuration data
• modify configurations
• read operational device status

Unlike traditional REST APIs, RESTCONF uses standardized YANG data models.

This enables multiple vendors and devices to be managed in a more consistent way.

Example - Retrieving information about SONiC switch interfaces

curl -k \
-u admin:YourPaSsWoRd \
-H "Accept: application/yang-data+json" \
https://switch-ip/restconf/data/openconfig-interfaces:interfaces

Example - VLAN 100 configuration on the SONiC Switch

curl -k -X POST "https://switch-ip/restconf/data/openconfig-interfaces:interfaces" \
     -H "Content-Type: application/yang-data+json" \
     -u "admin:YourPaSsWoRd" \
     -d '{
       "openconfig-interfaces:interface": [
         {
           "name": "Vlan100",
           "config": {
             "name": "Vlan100"
           }
         }
       ]
     }'

Advantages of RESTCONF

• more standardized than traditional REST APIs
• easier multi-vendor automation
• integration with YANG models

• modern network management approach

   

Limitations of RESTCONF

• less widely supported than REST API
• some vendors implement only partial functionality

• requires understanding of YANG models

   

When Should You Use RESTCONF?

RESTCONF is a good choice when:

• building modern automation platforms
• using devices with YANG support
• standardization is important

What Is NETCONF?

NETCONF (Network Configuration Protocol) is a protocol specifically designed for network device configuration management.

NETCONF operates over SSH and uses XML for data exchange.

It is commonly used by telecom operators and large enterprise or data center environments.

How Does NETCONF Work?

NETCONF provides:

• secure configuration management
• configuration validation before deployment
• rollback functionality

• transactional configuration operations

   

Example Workflow

1. The automation system sends a new configuration
2. The device validates the configuration
3. Changes are applied only after confirmation

This significantly reduces the risk of configuration errors.

Example - NETCONF XML Request

<get-config>
  <source>
    <running/>
  </source>
</get-config>

Advantages of NETCONF

• strong security
• excellent configuration control
• transactional operations
• standardized architecture

• YANG model support

   

Limitations of NETCONF

• more complex than REST APIs
• XML is less human-readable

• requires greater technical knowledge

   

When Should You Use NETCONF?

NETCONF is well suited when:

• managing large infrastructures
• configuration reliability is critical
• change validation is required
• building carrier-grade environments

What Is gNMI?

gNMI (gRPC Network Management Interface) is a modern network automation and telemetry protocol.

It was designed for:

• data centers
• cloud environments

• large-scale infrastructures

   

gNMI uses:

• gRPC
• Protocol Buffers (Protobuf)

• YANG models

   

How Does gNMI Work?

gNMI enables:

• device configuration
• telemetry data collection
• real-time data streaming

The biggest difference compared to older protocols is continuous telemetry streaming.

Devices can automatically send network status updates without constant polling from monitoring systems.

Use case - Retrieving interface telemetry data on Broadcom SONiC

Example - Get interface stats

gnmic -a switch-ip:8080 \
-u admin \
-p YourPaSsWoRd \
--skip-verify \
get \
--path /interfaces/interface[name=Ethernet0]/state/counters \
-e json_ietf

Example - Real-time telemetry streaming

gnmic -a switch-ip:8080 \
-u admin \
-p password \
--insecure \
subscribe \
--path /openconfig-interfaces:interfaces/interface[name=Ethernet0]/state/counters \
--mode sample \
--sample-interval 5s

Important Note

Before using the gnmic examples shown in this article, ensure that:

• the telemetry (gNMI) container is running on the SONiC switch;
• the gNMI service is listening on the configured TCP port;
• network connectivity exists between the management workstation and the switch;
• valid user credentials are available;
• the gnmic client is installed on the management workstation.

Advantages of gNMI

• very high performance
• real-time telemetry
• modern architecture

• excellent scalability

   

Limitations of gNMI

• more complex deployment
• requires modern hardware and software support

• limited compatibility with older infrastructure

   

When Should You Use gNMI?

gNMI is a good choice when:

• building modern data centers
• requiring real-time telemetry
• managing very large infrastructures
• scalability and performance are critical

What Is SNMP?

SNMP (Simple Network Management Protocol) is one of the oldest network management protocols.

For many years, it was the primary method used for monitoring network devices.

SNMP is still widely used in network monitoring systems today.

How Does SNMP Work?

SNMP enables:

• reading device parameters
• monitoring infrastructure status

• receiving alarms and notifications (SNMP Traps)

   

Example

A monitoring system can collect:

• CPU utilization
• device temperature
• interface status
• packet error counters

Example - Checking interface status on SONiC switch

snmpwalk -v 2c -c public switch-ip IF-MIB::ifOperStatus

Alternative Example - Using RAW OID

snmpwalk -v 2c -c public switch-ip 1.3.6.1.2.1.2.2.1.8

Important Note

Before using the SNMP examples shown in this article, ensure that:

• SNMP is enabled on the SONiC switch.
• A read-only SNMP community is configured.
• The management workstation has network connectivity to the switch.
• SNMP utilities are installed on the management workstation.
• SNMP MIB packages are installed if symbolic names such as IF-MIB::ifOperStatus are used.

Security Recommendation

Modern environments should use SNMPv3 whenever possible due to improved authentication and encryption capabilities.

Advantages of SNMP

• extremely wide vendor support
• simple deployment
• compatibility with legacy hardware

• commonly supported by monitoring systems

   

Limitations of SNMP

• limited configuration capabilities
• older architecture
• less efficient telemetry

• security concerns in older SNMP versions

   

When Should You Use SNMP?

SNMP is a good choice when:

• monitoring legacy infrastructure
• using traditional NMS platforms
• requiring basic monitoring capabilities