Cisco Systems 3130 User Manual

shows the queueing and scheduling flowchart for ingress ports.

SRR services the priority queue for its configured share before servicing the other queue.

The switch supports two configurable ingress queues, which are serviced by SRR in shared mode only. 

 describes the queues.

86693

Read QoS label

(DSCP or CoS value).

Determine ingress queue
number, buffer allocation,

and WTD thresholds.

Are thresholds

being exceeded?

Queue the packet. Service

the queue according to

the SRR weights.

Send packet to

the stack ring.

Drop packet.

Start

Yes

No

1.

The switch uses two nonconfigurable queues for traffic that is essential for proper network and stack operation.

Normal 

User traffic that is considered to be normal priority. You can configure three different 
thresholds to differentiate among the flows. You can use the mls qos srr-queue input 
threshold, the mls qos srr-queue input dscp-map, and the mls qos srr-queue input 
cos-map global configuration commands.

Expedite

High-priority user traffic such as differentiated services (DF) expedited forwarding or 
voice traffic. You can configure the bandwidth required for this traffic as a percentage 
of the total traffic or total stack traffic by using the mls qos srr-queue input 
priority-queue global configuration command. The expedite queue has guaranteed 
bandwidth.