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Article ID: 2743

Configuration of CoS/802.1p to Queue Mapping on Sx500 Series Stackable Switches


The Class of Service (CoS)/802.1p mapping is used to classify the outgoing traffic at the egress port (outgoing port) based on the 802.1p priority in the VLAN ID tag. The incoming packets to the egress ports are then prioritized based on their assigned egress values or queue values (1 to 4). This article explains how to map the output queue to the corresponding 802.1p priority levels on the Sx500 Series Stackable Switch.

The Quality of Service (QoS) feature must be enabled and in the CoS/802.1p trusted mode to assign the queue mapping. Please refer to the article, Quality of Service (QoS) Queue Settings on Sx500 Series Stackable Switches for this configuration.

Applicable Devices

• Sx500 Series Stackable Switches

Software Version


Map CoS/802.1p to Queue

Step 1. Log in to the web configuration utility to choose Quality of Service > General > CoS/802.1p to Queue. The CoS/802.1p to Queue page opens:

The CoS/802.1p to Queue Table contains the following information:

• 802.1p – Displays the 802.1p priority tag values to be assigned to an output queue, where 0 is the lowest priority and 7 is the highest.

— 0 – Background. The data that is least prioritized like bulk transfers, games etc.

— 1 – Best Effort. The data which needs best-effort delivery on ordinary LAN priority. The network does not provide any guarantee on delivery, but the data obtains unspecified bit rate and delivery time based upon the traffic.

— 2 – Excellent Effort. The data that needs best effort delivery for important users.

— 3 – Critical Application like Linux Virtual Server (LVS) phone Session Initiation Protocol (SIP).

— 4 – Video. Latency and Jitter less than 100 ms.

— 5 – Voice Cisco IP phone default. Latency and Jitter less than 10 ms.

— 6 – Inter network Control LVS phone Real-time Transport Protocol (RTP).

— 7 – Network Control. High requirement to get through to maintain and support the network infrastructure.

• Output Queue — Displays the egress queue to which the 802.1p priority is mapped.

Step 2. Choose the desired output queue for each 802.1p priority from the drop-down list under the Output Queue column of the CoS/802.1p to Queue Table. The drop-down list has four queues where Queue 4 is the highest priority output queue and Queue 1 is the lowest priority.

Step 3. Click Apply to save the settings.

Step 4. (Optional) Click Restore Defaults to restore the output queues to the default settings.

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