Automation & APIs

Modern networks are programmed, not typed. The data formats, APIs and tools that make it happen.

// data formats

JSON	Lightweight key/value — most APIs
XML	Verbose tags — NETCONF
YAML	Human-friendly — Ansible

// REST verbs (CRUD)

GET	Read
POST	Create
PUT / PATCH	Update
DELETE	Remove

// network APIs & models

REST: HTTP CRUD over JSON, stateless
NETCONF: XML over SSH (port 830)
RESTCONF: REST-style over HTTP
YANG: data model for config & state
gNMI: streaming telemetry over gRPC

// tools

Ansible	Agentless, YAML playbooks, push
Terraform	Declarative IaC, state-based
Python	netmiko / NAPALM / requests
Puppet / Chef	Agent-based, pull model

// SDN

Separates control plane from data plane
A central controller programs the devices
Northbound API (apps) / Southbound API (devices)
Intent-based networking automates policy

// management interfaces

NETCONF	XML over SSH · 830	Transactional config (candidate → commit)
RESTCONF	JSON/XML over HTTPS · 443	REST-style access to YANG data
gNMI	protobuf over gRPC	Streaming telemetry & config
SNMP	UDP 161	Legacy polling (read-mostly)

// IaC principles

Idempotent — re-running yields the same state
Declarative (desired state) vs imperative (steps)
Store configs in Git — GitOps source of truth
CI/CD pipeline tests config before pushing
Render → deploy → verify, automatically

automate · python (netmiko)

# Python — push config with netmiko
from netmiko import ConnectHandler
dev = {"device_type":"cisco_ios","host":"10.0.0.1",
       "username":"admin","password":"***"}
with ConnectHandler(**dev) as c:
    c.send_config_set(["interface Gi0/1",
                       "description uplink","no shutdown"])
    print(c.send_command("show ip int brief"))

restconf · curl

# RESTCONF — read interfaces (JSON over HTTPS)
curl -sk -u admin:*** \
  -H "Accept: application/yang-data+json" \
  https://10.0.0.1/restconf/data/ietf-interfaces:interfaces