Technical data

BLADE OS 5.1 Application Guide
BMD00136, November 2009 Chapter 7: Quality of Service
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Ingress packets receive a priority value, as follows:
 Tagged packets—G8000 reads the 802.1p priority in the VLAN tag.
 Untagged packets—G8000 tags the packet and assigns an 802.1p priority, based on the port’s
default priority.
Egress packets are placed in a COS queue based on the priority value, and scheduled for
transmission based on the scheduling weight of the COS queue.
802.1p Configuration Example
1. Configure a port’s default 802.1p priority.
2. Map the 802.1p priority value to a COS queue and set the COS queue scheduling weight.
Queuing and Scheduling
The G8000 can be configured to have either 2 or 8 output Class of Service (COS) queues per port,
into which each packet is placed. Each packet’s 802.1p priority determines its COS queue, except
when an ACL action sets the COS queue of the packet.
Each COS queue uses Weighted Round Robin (WRR) scheduling, with user configurable weight
from 1 to 15. The weight of 0 (zero) indicates strict priority, which might starve the low priority
queues.
You can configure the following attributes for COS queues:
 Map 802.1p priority value to a COS queue
 Define the scheduling weight of each COS queue
Use the following command to configure COS queues.
>> # interface port 1
>> # dot1p <802.1p value (0-7)>
>> # qos transmit-queue mapping <802.1p value> <COSq number>
>> # qos transmit-queue weight-cos <COSq number> <COSq weight (0-15)>
>> # qos transmit-queue