4.3 QoS Policy Design
| Field |
Value |
| Document ID |
SDWAN-POL-4.3 |
| Version |
1.0 |
| Last Updated |
December 2025 |
| Author |
Network Architecture Team |
| Classification |
Internal Use |
1. Executive Summary
This section documents the Quality of Service (QoS) policy design for Abhavtech's SD-WAN deployment. The QoS framework ensures consistent application performance across all WAN transports through classification, marking, queuing, and shaping mechanisms.
1.1 QoS Architecture
+------------------------------------------------------------------+
| SD-WAN QoS ARCHITECTURE |
+------------------------------------------------------------------+
| |
| Ingress (LAN → WAN) |
| +----------------------------------------------------------+ |
| | 1. Classification 2. Marking 3. Queuing | |
| | +----------------+ +-------------+ +---------------+ | |
| | | NBAR2 / ACL |->| DSCP Set |->| 8 Queues | | |
| | | Match criteria | | Per class | | Per transport | | |
| | +----------------+ +-------------+ +---------------+ | |
| +----------------------------------------------------------+ |
| |
| Egress (WAN → LAN) |
| +----------------------------------------------------------+ |
| | 1. Rewrite 2. Schedule 3. Shape | |
| | +-------------+ +---------------+ +---------------+ | |
| | | DSCP Trust |->| CBWFQ + LLQ |->| Interface | | |
| | | or Remark | | Per class | | Shaper | | |
| | +-------------+ +---------------+ +---------------+ | |
| +----------------------------------------------------------+ |
| |
+------------------------------------------------------------------+
1.2 QoS Model Summary
| Component |
Method |
Configuration |
| Classification |
NBAR2, DSCP, ACL |
Policy map |
| Marking |
DSCP rewrite |
Per-class |
| Queuing |
8 queues per interface |
Template |
| Scheduling |
CBWFQ + LLQ |
Bandwidth % |
| Shaping |
Per-interface |
Circuit speed |
2. Traffic Classification
2.1 Traffic Class Definitions
+------------------------------------------------------------------+
| TRAFFIC CLASS MATRIX |
+------------------------------------------------------------------+
| |
| Class | DSCP | PHB | % BW | Queue | Priority |
| -----------------+--------+------+------+-------+--------------|
| Voice | EF(46) | EF | 10% | LLQ | Strict |
| Video-Realtime | AF41 | AF41 | 20% | Q1 | High |
| Video-Streaming | AF31 | AF31 | 10% | Q2 | Medium-High |
| Business-Critical| AF21 | AF21 | 20% | Q3 | Medium |
| Signaling | CS3 | CS3 | 5% | Q4 | Medium |
| Transactional | AF11 | AF11 | 15% | Q5 | Low-Medium |
| Best-Effort | DF(0) | BE | 15% | Q6 | Low |
| Scavenger | CS1 | CS1 | 5% | Q7 | Lowest |
| |
| Total: 100% |
| |
+------------------------------------------------------------------+
2.2 Classification Configuration
! Class Maps for Traffic Classification
class-map match-any CM-VOICE
match dscp ef
match protocol cisco-phone
match protocol sip
match protocol rtp audio
class-map match-any CM-VIDEO-REALTIME
match dscp af41
match protocol cisco-webex
match protocol ms-teams
match protocol zoom
class-map match-any CM-VIDEO-STREAMING
match dscp af31
match protocol youtube
match protocol netflix
match protocol vimeo
class-map match-any CM-BUSINESS-CRITICAL
match dscp af21
match protocol salesforce
match protocol sap
match protocol oracle-db
class-map match-any CM-SIGNALING
match dscp cs3
match protocol sip-tls
match protocol h323
class-map match-any CM-TRANSACTIONAL
match dscp af11
match protocol http
match protocol https
match protocol ms-office-365
class-map match-any CM-SCAVENGER
match dscp cs1
match protocol bittorrent
match protocol windows-update
!
3. DSCP Marking
3.1 Marking Policy
! QoS Marking Policy (Applied to Service VPN Interfaces)
policy-map PM-QOS-MARKING
class CM-VOICE
set dscp ef
class CM-VIDEO-REALTIME
set dscp af41
class CM-VIDEO-STREAMING
set dscp af31
class CM-BUSINESS-CRITICAL
set dscp af21
class CM-SIGNALING
set dscp cs3
class CM-TRANSACTIONAL
set dscp af11
class CM-SCAVENGER
set dscp cs1
class class-default
set dscp default
!
! Apply to LAN interface
interface GigabitEthernet0/0/1
description "LAN - Service VPN 10"
service-policy input PM-QOS-MARKING
!
3.2 DSCP Preservation
+------------------------------------------------------------------+
| DSCP PRESERVATION |
+------------------------------------------------------------------+
| |
| Traffic Flow with DSCP: |
| |
| LAN Side IPsec Tunnel WAN Side |
| +--------+ +------------+ +--------+ |
| | Packet | | Outer: EF | | Packet | |
| | DSCP:EF|------>| Inner: EF |------>| DSCP:EF| |
| +--------+ +------------+ +--------+ |
| |
| Configuration: |
| - Copy inner DSCP to outer header |
| - Preserve DSCP across tunnel |
| - Trust DSCP on LAN interfaces |
| |
+------------------------------------------------------------------+
! DSCP Copy Configuration
sdwan
interface GigabitEthernet0/0/0
tunnel-interface
color mpls
qos-map
dscp-policy COPY-INNER-TO-OUTER
!
4. Queuing and Scheduling
4.1 Queue Structure
+------------------------------------------------------------------+
| 8-QUEUE MODEL |
+------------------------------------------------------------------+
| |
| Queue | Type | BW % | DSCP | Application |
| ---------+-------+-------+-------------+-----------------------|
| LLQ | LLQ | 10% | EF | Voice |
| Queue 1 | CBWFQ | 20% | AF41 | Video Realtime |
| Queue 2 | CBWFQ | 10% | AF31 | Video Streaming |
| Queue 3 | CBWFQ | 20% | AF21 | Business Critical |
| Queue 4 | CBWFQ | 5% | CS3 | Signaling |
| Queue 5 | CBWFQ | 15% | AF11 | Transactional |
| Queue 6 | CBWFQ | 15% | DF(0) | Best Effort |
| Queue 7 | CBWFQ | 5% | CS1 | Scavenger |
| |
| Scheduling: Strict Priority for LLQ, then weighted round-robin |
| |
+------------------------------------------------------------------+
4.2 Queuing Configuration
! QoS Scheduling Policy (Applied to WAN Interfaces)
policy-map PM-QOS-SCHEDULING
class CM-VOICE
priority percent 10
class CM-VIDEO-REALTIME
bandwidth percent 20
random-detect dscp-based
class CM-VIDEO-STREAMING
bandwidth percent 10
random-detect dscp-based
class CM-BUSINESS-CRITICAL
bandwidth percent 20
random-detect dscp-based
class CM-SIGNALING
bandwidth percent 5
queue-limit 64 packets
class CM-TRANSACTIONAL
bandwidth percent 15
random-detect dscp-based
class CM-SCAVENGER
bandwidth percent 5
random-detect dscp-based
class class-default
bandwidth percent 15
random-detect
!
! Apply to WAN interface
interface GigabitEthernet0/0/0
description "WAN - MPLS Transport"
service-policy output PM-QOS-SCHEDULING
!
5. Traffic Shaping
5.1 Interface Shaping
+------------------------------------------------------------------+
| TRAFFIC SHAPING |
+------------------------------------------------------------------+
| |
| Site | Transport | Circuit BW | Shape Rate | Buffer |
| ---------------+-----------+------------+------------+----------|
| Mumbai DC | MPLS | 1 Gbps | 950 Mbps | 250 ms |
| Mumbai DC | Internet | 500 Mbps | 480 Mbps | 250 ms |
| Chennai DR | MPLS | 500 Mbps | 480 Mbps | 250 ms |
| Bangalore | MPLS | 100 Mbps | 95 Mbps | 250 ms |
| Bangalore | Internet | 100 Mbps | 95 Mbps | 250 ms |
| London | MPLS | 200 Mbps | 190 Mbps | 250 ms |
| New Jersey | MPLS | 200 Mbps | 190 Mbps | 250 ms |
| |
+------------------------------------------------------------------+
5.2 Shaping Configuration
! Hierarchical QoS with Shaping
policy-map PM-WAN-SHAPER
class class-default
shape average 950000000
service-policy PM-QOS-SCHEDULING
!
! Apply to WAN interface
interface GigabitEthernet0/0/0
description "WAN - MPLS 1G"
service-policy output PM-WAN-SHAPER
!
! Per-Tunnel Shaping (vManage Template)
! Configured via Feature Template:
! - Shaper Rate: Match circuit speed
! - Per-tunnel QoS: Enabled
! - Adapt QoS: Enabled (for bandwidth changes)
6. Policing
6.1 Ingress Policing
! Police specific traffic classes
policy-map PM-INGRESS-POLICE
class CM-VIDEO-STREAMING
police rate 50000000 burst 1500000 peak-rate 75000000 peak-burst 2000000
conform-action transmit
exceed-action set-dscp-transmit af32
violate-action drop
class CM-SCAVENGER
police rate 10000000 burst 500000
conform-action transmit
exceed-action drop
class class-default
police rate 100000000 burst 3000000
conform-action transmit
exceed-action set-dscp-transmit default
!
6.2 Per-Application Rate Limiting
! Rate limit specific applications
policy-map PM-APP-RATE-LIMIT
class CM-YOUTUBE
police rate 25000000
conform-action transmit
exceed-action drop
class CM-SOCIAL-MEDIA
police rate 10000000
conform-action transmit
exceed-action drop
!
7. SD-WAN QoS Templates
7.1 vManage QoS Configuration
! SD-WAN Manager QoS Policy Template
policy
qos-map QOS-POLICY-ABHAV
qos-scheduler VOICE-QUEUE
class EF
bandwidth 10
scheduling llq
drops tail-drop
!
qos-scheduler VIDEO-RT-QUEUE
class AF41
bandwidth 20
scheduling wrr
drops red-drop
!
qos-scheduler VIDEO-STREAM-QUEUE
class AF31
bandwidth 10
scheduling wrr
drops red-drop
!
qos-scheduler BUSINESS-CRIT-QUEUE
class AF21
bandwidth 20
scheduling wrr
drops red-drop
!
qos-scheduler SIGNALING-QUEUE
class CS3
bandwidth 5
scheduling wrr
drops tail-drop
!
qos-scheduler TRANSACTION-QUEUE
class AF11
bandwidth 15
scheduling wrr
drops red-drop
!
qos-scheduler BEST-EFFORT-QUEUE
class default
bandwidth 15
scheduling wrr
drops red-drop
!
qos-scheduler SCAVENGER-QUEUE
class CS1
bandwidth 5
scheduling wrr
drops red-drop
!
!
!
7.2 Adaptive QoS
+------------------------------------------------------------------+
| ADAPTIVE QOS |
+------------------------------------------------------------------+
| |
| Feature: Automatically adjusts QoS based on path conditions |
| |
| Scenario 1: Full Bandwidth Available |
| +----------------------------------------------------------+ |
| | Voice: 10% of 100 Mbps = 10 Mbps | |
| | Video: 20% of 100 Mbps = 20 Mbps | |
| +----------------------------------------------------------+ |
| |
| Scenario 2: Path Degraded (50 Mbps available) |
| +----------------------------------------------------------+ |
| | Voice: 10% of 50 Mbps = 5 Mbps (LLQ maintained) | |
| | Video: 20% of 50 Mbps = 10 Mbps (proportional) | |
| | Scavenger: Heavily throttled | |
| +----------------------------------------------------------+ |
| |
+------------------------------------------------------------------+
! Enable Adaptive QoS
sdwan
interface GigabitEthernet0/0/0
tunnel-interface
adapt-qos
!
8. QoS Verification
8.1 Verification Commands
! Verify QoS policy application
show policy-map interface GigabitEthernet0/0/0
! Verify queue statistics
show sdwan policy qos-scheduler-info
! Verify class drops
show policy-map interface GigabitEthernet0/0/0 class CM-VOICE
! Verify DSCP marking
show class-map
! Real-time QoS statistics
show sdwan tunnel statistics
! Per-application QoS
show sdwan app-route statistics
8.2 QoS Monitoring Dashboard
+------------------------------------------------------------------+
| QOS MONITORING DASHBOARD |
+------------------------------------------------------------------+
| |
| Queue Statistics (Mumbai DC - MPLS): |
| +----------------------------------------------------------+ |
| | Queue | Packets In | Packets Out | Drops | % Drop | |
| +----------------------------------------------------------+ |
| | Voice LLQ | 1,245,678 | 1,245,678 | 0 | 0.00% | |
| | Video RT | 5,678,901 | 5,650,234 | 28,667 | 0.50% | |
| | Business | 8,901,234 | 8,876,543 | 24,691 | 0.28% | |
| | Best Effort| 12,345,678 | 11,987,654 | 358,024 | 2.90% | |
| | Scavenger | 2,345,678 | 2,100,123 | 245,555 | 10.5% | |
| +----------------------------------------------------------+ |
| |
| DSCP Distribution: |
| EF: ████░░░░░░ 12% |
| AF41: ██████████ 25% |
| AF21: ████████░░ 20% |
| DF: ██████████████████████ 43% |
| |
+------------------------------------------------------------------+
9. Best Practices Summary
9.1 Classification Best Practices
- Use NBAR2 for application-based classification
- Trust DSCP from known endpoints (IP phones, video)
- Re-mark untrusted traffic at network edge
- Document classification criteria
9.2 Queuing Best Practices
- Reserve LLQ bandwidth for voice (<= 33% of link)
- Use WRED for TCP-based applications
- Size queues appropriately for latency requirements
- Monitor queue depths regularly
9.3 Shaping Best Practices
- Shape to 95% of circuit speed to avoid ISP drops
- Enable adaptive QoS for dynamic environments
- Test failover scenarios with reduced bandwidth
- Coordinate with ISP QoS policies
References
| Document |
Description |
Location |
| Cisco SD-WAN QoS Guide |
Official QoS documentation |
cisco.com |
| Enterprise QoS Design |
QoS best practices |
cisco.com |
| Abhavtech QoS Standards |
Internal QoS requirements |
SharePoint |
Document Version: 1.0
Last Updated: December 2025
Classification: Internal Use
Document ID: SDWAN-POL-4.3