A network engineer is troubleshooting intermittent connectivity issues for users connecting remotely to the corporate network via a VPN. Users report slow application response times and occasional disconnections, particularly when transferring large files. The engineer needs to identify potential bottlenecks and packet loss across the VPN tunnel and the underlying internet path. Which network assurance tool or technique would provide the MOST relevant insights?
- AIP SLA operations configured on routers along the path
- BSNMP polling of VPN concentrator CPU and memory utilization
- CBasic `ping` and `tracert` commands from the user's machine
- DNetFlow/IPFIX data analysis on edge routers
Show answer & explanationAnswer & explanation
Correct answer: A. IP SLA operations configured on routers along the path
IP SLA (Service Level Agreement) operations actively generate synthetic traffic to measure network performance metrics like latency, jitter, and packet loss between specific points. This allows for proactive identification of performance degradation across the VPN tunnel and the underlying path, providing more detailed and continuous insight than basic diagnostic tools or reactive SNMP polling.
Why the other options are wrong
- B. SNMP polling provides device health, but not end-to-end path performance metrics or specific details about packet loss and latency across the VPN tunnel itself.
- C. Ping and tracert provide basic, point-in-time reachability and hop information, but don't offer continuous performance metrics like jitter or detailed packet loss over time.
- D. NetFlow/IPFIX provides details about actual traffic flows (who, what, where, when), but it doesn't actively measure network performance metrics or proactively identify degradation like IP SLA does.
Cisco IP SLA
Cisco IP Service Level Agreement (SLA) is a technology that allows network performance to be measured and monitored by generating synthetic traffic and collecting statistics.
- Measures network performance metrics (latency, jitter, packet loss, availability).
- Uses synthetic traffic to test specific paths or applications.
- Can be used for proactive monitoring and path selection in routing.
- Supports various operations like ICMP echo, UDP echo, HTTP, DNS, etc.
Memory trick: Troubleshooting: Ping/Tracert for basic, SNMP for health, IP SLA for path, NetFlow for traffic.