Quality of Service (QoS)
QoS (IEEE 802.1p) can play a very important role in your network as it helps prioritize and reliably deliver certain types of data with the use of Differentiated services model. "DiffServ" implements the prioritized model by marking packets according to the type of service they desire. In response to these markings, routers and switches use various queueing strategies to tailor performance to expectations.
Meraki MS series switches support adding and honoring of DSCP tags. The Differentiated Services Code Point (DSCP) bits in the packet header are set to inform the switches which Class-of-Service (CoS) queue should be used.
Configuring QoS on your Meraki switches is done at the Network level which means that it automatically applies to all of the switches in the Meraki Network. In order to enable and configure QoS, navigate to Switch > Configure > Switch Settings. In the Quality of Service section, add the rules desired for trusting or applying DSCP tags based on the protocol (UDP, TCP), source and destination ports.
In Figure 1 below, QoS has been configured to apply DSCP tags for a Shoretel VoIP solution as well as a video streaming service that traverses the MS series switch. As packets that match the QoS rules traverse the switch, DSCP tags are added or honored. When a packet must be forwarded from an interface with queuing, packets requiring low jitter (e.g., VoIP or videoconferencing) are given priority over packets in other queues.
In addition, you can edit the default DSCP to CoS mapping as well. If you do not specify a mapping for DSCP value to CoS, the default CoS value assigned will be 0.