4.0 Network Assurance

Network Assurance is how you prove what the network is doing.

Routing and switching build the path. Assurance verifies the path, measures it, mirrors it, exports it, and manages it with controllers and APIs. Do not study these tools as isolated trivia. Study them as a troubleshooting ladder:

1. Can I reach it? Ping and traceroute.
2. What changed? Syslog and counters.
3. What is the device doing right now? Debugs and conditional debugs.
4. What traffic is using the network? Flexible NetFlow.
5. What is inside the packets? SPAN, RSPAN, ERSPAN.
6. Is a service meeting a threshold? IP SLA.
7. Can a controller correlate and act? Cisco Catalyst Center.
8. Can software read or change state through a model? NETCONF and RESTCONF.

Articles

• 4.1 Diagnose network problems
• 4.2 Configure and verify Flexible NetFlow
• 4.3 Configure SPAN, RSPAN, and ERSPAN
• 4.4 Configure and verify IP SLA
• 4.5 Cisco Catalyst Center assurance workflows
• 4.6 Configure and verify NETCONF and RESTCONF

Study plan

Read one article, then do the lab. These topics are not hard because the commands are long. They are hard because students mix up the purpose of each tool. NetFlow is not a packet capture. SPAN is not a long-term trend tool. IP SLA is not a controller. NETCONF and RESTCONF are not screen-scraping.

Keep the tool-purpose mapping tight and the exam questions get easier.