Advanced QoS on Cisco Catalyst: Ensuring Quality of Service
·1 min read·191 words
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.