Scheduling - Supermicro SSE-X3348S Configuration Manual

The traffic class is taken from the CoS value of the ingress packet. If an ingress packet does not have a
CoS (untagged packets), the port default priority will be used.
Packet 1 with CoS 3
Packet 2 with CoS 7
Ingress Packets
Figure QoS-3: Egress Queuing
The above figure shows the egress queuing procedure. When a tagged packet with CoS value 3(packet1)
arrives in the switch, the CoS to egress queuemapping for the particular destination port is lookedup.
Based on CoS to egress queue mapping, packets with CoS value 3 are queued in Queue-3 and
transmitted. Similarly, when a tagged packet with CoS value 7(packet2) arrives in switch, the CoS to
egress queue mapping for the particular destination port is lookedup. Based on CoS to egress queue
mapping, packets with CoS value 7 are queued in Queue-7 and transmitted

1.3.2 Scheduling

Supermicro switches support eight CoS queues for each egress port. For each of the eightqueues,
various typesof scheduling can be configured:
Strict Priority
Strict priority scheduling is based on the priority of queues. Packets in ahigh-priority queue arealways
sent first and packets in alow-priority queue are not sent until all the high-priority queuesareempty.
Round Robin(RR)
Using the round-robin (RR) scheduling algorithm, packets in queues are transmitted in a FIFO
manner,i.e. one packet after the other. All queues havethe same priority and weight in an RR
configuration.
CoS Traffic Class
0 0
1 1
2 2
3 3
4 4
5 5
6 6
7 7
CoS-to-Traffic-class mappingEgress QueueEgress Packets
Supermicro L2/L3 Switches Configuration Guide
0
Packet 1 with CoS 3
1
2
3 Pkt1
4
5
6
Packet 2 with CoS 7
7 Pkt 2
.
8