Hey @Herman2018
To configure QoS for voice traffic in an MPLS environment on a Cisco Catalyst 9300 switch that is functioning as both a PE (Provider Edge) and CE (Customer Edge) device, you need to ensure that voice traffic is prioritized appropriately. This involves classifying, marking, and queuing traffic to ensure voice traffic gets the necessary priority.
Below is a step-by-step guide to configuring QoS for voice traffic on the Catalyst 9300:
1. Enable QoS Globally
QoS is not enabled by default on Catalyst 9300 switches. You need to enable it globally.
2. Classify and Mark Voice Traffic
You need to classify voice traffic and mark it with the appropriate DSCP (Differentiated Services Code Point) value. Voice traffic typically uses DSCP EF (Expedited Forwarding, DSCP value 46).
Example: Classify Voice Traffic Using an Access Control List (ACL)
Create an ACL to match voice traffic (e.g., based on UDP ports for RTP traffic).
conf t
ip access-list extended VOICE-TRAFFIC
permit udp any any range 16384 32767
exit
Create a Class Map to Match the ACL
conf t
class-map match-any VOICE
match access-group name VOICE-TRAFFIC
Create a Policy Map to Mark Voice Traffic
Mark the traffic with DSCP EF (46).
conf t
policy-map MARK-VOICE
class VOICE
Apply the Policy Map to the Input Interface
Apply the policy map to the interface where the traffic enters the switch.
conf t
interface GigabitEthernet1/0/1
service-policy input MARK-VOICE
3. Configure Queuing and Scheduling
After marking the traffic, you need to configure queuing to ensure voice traffic is prioritized. Catalyst 9300 switches use Modular QoS CLI (MQC) for queuing.
Create a Policy Map for Queuing
Create a policy map to prioritize voice traffic using a low-latency queue (LLQ).
conf t
policy-map QUEUE-VOICE
class VOICE
priority level 1
class class-default
bandwidth remaining percent 90
- The
priority command ensures that voice traffic is placed in the low-latency queue and is serviced first.
- The
class-default ensures other traffic gets the remaining bandwidth.
Apply the Policy Map to the Output Interface
Apply the queuing policy to the output interface.
conf t
interface GigabitEthernet1/0/2
service-policy output QUEUE-VOICE
4. Configure MPLS QoS (if applicable)
If MPLS QoS is required, you need to map the DSCP values to MPLS EXP bits. This ensures that the QoS markings are preserved across the MPLS backbone.
Map DSCP to MPLS EXP
conf t
mpls qos map dscp-exp
dscp 46 exp 5
This maps DSCP EF (46) to MPLS EXP value 5.
Enable MPLS QoS on the Interface
conf t
interface GigabitEthernet1/0/3
mpls qos
5. Verify the Configuration
Use the following commands to verify your QoS configuration:
-
Check QoS settings on an interface:
show mls qos interface GigabitEthernet1/0/1
-
Verify policy map configuration:
show policy-map interface GigabitEthernet1/0/2
-
Verify DSCP-to-EXP mapping:
-
Check QoS statistics:
6. Additional Considerations
-
Trust Boundaries: If the Catalyst 9300 is connected to IP phones, configure the switch to trust the DSCP markings from the phones.
interface GigabitEthernet1/0/4
mls qos trust dscp
-
Policing: If you need to limit the bandwidth for voice traffic, you can configure policing in the policy map.
-
VRF Considerations: Since the Catalyst 9300 is acting as both a PE and CE device, ensure that the QoS policies are applied within the correct VRF context if necessary.
By following these steps, you can configure QoS for voice traffic in your MPLS environment on the Catalyst 9300 switch. This ensures that voice traffic is prioritized and meets the required performance standards.
Hope This Helps!!!
AshSe
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