Question

Difficulty: Very hardNetwork Performance Monitoring and Metrics

A network administrator is investigating intermittent VoIP audio degradation across an enterprise WAN link connecting two branch offices. Telephony logs indicate elevated packet loss and jitter during peak operational hours. Corporate security policy dictates that all infrastructure monitoring must utilize encrypted payload data and cryptographic authentication to prevent packet interception on intermediate links. Additionally, the administrator must gather interface bandwidth utilization baselines alongside granular protocol flow analysis to isolate the source of network congestion. Which of the following protocol and security level combinations correctly fulfills both operational and security requirements?

  1. Configure SNMPv3 using the authPriv security level for interface metric polling, and deploy IPFIX to export traffic flow statistics for jitter analysis.Answer
  2. B
    Configure SNMPv3 using the authNoPriv security level for interface metric polling, and configure Syslog over UDP port 514 to capture traffic metrics.
  3. C
    Configure SNMPv2c with encrypted community strings over UDP port 161 for interface polling, and use sFlow over TCP port 161 to track voice jitter statistics.
  4. D
    Configure SNMPv3 using the noAuthNoPriv security level for interface polling, and rely on ICMP ECHO tracking over UDP port 53 to collect baseline utilization values.

Answer

Configure SNMPv3 using the authPriv security level for interface metric polling, and deploy IPFIX to export traffic flow statistics for jitter analysis.
The correct option fulfills both requirements: SNMPv3 at the authPriv security level provides cryptographic authentication as well as payload encryption (privacy) using AES or DES, meeting the strict enterprise security mandate. Additionally, IPFIX (IP Flow Information Export) is an industry-standard protocol for analyzing flow data such as VoIP jitter, latency, and packet loss across WAN links.

Step-by-Step Solution

1
Analyze security policy requirements for SNMP device polling.
Identified that cryptographic authentication and payload encryption are mandatory for all management polling across untrusted WAN links.
Security mandates require privacy (encryption) in addition to authentication.
2
Evaluate SNMP version and security mode capabilities.
Determined SNMPv3 authPriv is the only mode providing both cryptographic authentication (SHA/MD5) and packet payload encryption (AES/DES).
SNMPv1 and SNMPv2c communicate in cleartext. SNMPv3 authNoPriv encrypts password hashes but leaves metrics payloads unencrypted.
3
Select the appropriate traffic monitoring mechanism for VoIP jitter and packet loss analysis.
Selected IPFIX (or NetFlow) for exporting connection-level flow records.
IPFIX/NetFlow captures flow-level telemetry necessary to identify application-specific performance issues such as VoIP jitter and bandwidth consumption.

Key Concept

SNMPv3 Security Levels and Network Flow Telemetry Integration
Rate this question