Use case: Customer has purchased 15MB MPLS line from service provider. They want to utilize this 15MB bandwidth for their import production traffic. Customer wants to allocate bandwidth as per below requirement just to make sure that their important traffic doesn’t get drop during congestion.

                           Video/Voice :                               3M   Guaranteed rate

                           Business (SAP/AD/WINSCP)     12M  Guaranteed rate

                           Others                                         10M Transmit rate

Solution:

Versa Flex VNF supports 16 forwarding classes. These forwarding classes are mapped with 4 traffic classes and each traffic class has 4 queues. Traffic classes are handled in strict priority order: network-control > expedited-forwarding > assured-forwarding > Best-effort. As per above requirement we need to map customer traffic with 3 traffic class.

So in this use case we need to map customer traffic as below. For simplicity we are matching different traffic on different port numbers however we can differentiate traffic based on other parameters as well (i.e. source ip, destination ip) 

Guaranteed Rate (CIR) – This would be available per traffic class at any point in time ( assuming no traffic in high priority traffic class)

Transmit Rate – This is the maximum rate that would be available per traffic class when there is no congestion

Topology:

Configuration:

Step 1: Configure QoS Profiles.

            Go to Appliance > Configuration> Networking tab> Class of Service> QoS Profiles and then click on + button.

Step 2: Configure QoS-policy

Go to Appliance > Configuration> Networking tab> Class of Service> QoS Policies and then click on + button.

There can be only one qos-policy.  By-default there is ‘Default-policy’ is configured so we can just delete the default one and create new policy.

Step 3: Configure QoS policy rules.

Go to Appliance > Configuration> Networking tab> Class of Service> QoS Policies> rules and then click on + button.

Match source and destination. Here source zone is “Intf-LAN1-Zone” and destination zone is “ptvi”.

Since we are differentiating traffic based on port numbers so we need to match port numbers under Headers/Schedule tab.

Map QoS profile

Similarly, we need to create rules for other profiles.

Step 4: Configure Schedulers

Go to Appliance > Configuration> Networking tab> Class of Service> Schedulers and then click on + button.

Configure scheduler for Voice/Video traffic and specify Guaranteed rate of 3M

For Business class we need to specify weights of each queue. Bandwidth allocation happens in proportion of weight.

Step 5: Configure Scheduler Maps

Go to Appliance > Configuration> Networking tab> Class of Service> Scheduler Maps and then click on + button.

In Schedular Map we need to associate schedulers with appropriate traffic classes.

Step 6: Configure shaping rate on vni interface.

Go to Appliance > Configuration> Networking tab> Class of Service> Associate Interface/Network and then click on + button.

On vni interface we need to specify shaping rate/burst size and Scheduler Map

Burst size selection: Default burst size for shaper is 125000 Byte for 1 Gbps and 12500 Byte for 100Mbps port speeds.

Burst size needs to be tune based on traffic nature as it affects shaping rate. Choosing burst size too large may cause shaper to allow traffic more than the specified rate. Also choosing burst size too low may result in less shaping than the specified rate.