Advanced QoS on Cisco Catalyst: Ensuring Quality of Service

Advanced QoS on Cisco Catalyst 9300: MQC (Modular QoS CLI), NBAR2 L7 classification, LLQ + CBWFQ, and auto-QoS. Production deployment with VoIP MOS testing. Expert Catalyst 9000 guide for 2026.

Hierarchical Model

• Classification: identify traffic (ACL, DSCP, NBAR)
• Marking: set DSCP at ingress
• Policing: input rate limiting
• Shaping: smooth output traffic
• Queuing: LLQ (priority) + CBWFQ (bandwidth per class)
• WRED: proactive packet dropping

NBAR2 (Network-Based Application Recognition)

• L7 detection: identifies applications (Teams, Zoom, Office365, Salesforce)
• Deep Packet Inspection
• 1400+ supported protocols
• Signature updates from Cisco

MQC Configuration

• class-map match-any VOICE
• match ip dscp ef
• match protocol rtp audio
• class-map match-any VIDEO
• match ip dscp af41
• match protocol cisco-jabber-video
• policy-map WAN-OUT
• class VOICE
• priority percent 10
• class VIDEO
• bandwidth percent 30
• class class-default
• bandwidth percent 25
• random-detect dscp-based
• interface GigabitEthernet0/0
• service-policy output WAN-OUT

Auto-QoS

• Nearly automatic configuration
• auto qos voip trust (IP phones)
• auto qos video cts (Cisco TelePresence)
• Generates MQC optimized according to Cisco best practices

QoS Testing

• Cisco IP SLA: latency/jitter/loss testing
• VoIP MOS score: target >4.0
• iperf: bandwidth validation
• Wireshark RTP analysis

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Advanced QoS configuration for Catalyst 9300. VoIP/video tuning. MOS testing. Quote within 48 hours.