Section 15. configuring services, Section 15.configuring services, Section title“configuring services – Allied Telesis AT-S95 WEB User Manual
Page 199
Configuring Services
Page 199
Section 15. Configuring Services
This section describes Quality of Service related configurations. QoS supports activating one of the following Trust
settings:
•
VLAN Priority Tag
•
DiffServ Code Point
•
None
Only packets that have a Forward action are assigned to the output queue, based on the specified classification.
By properly configuring the output queues, the following basic mode services can be set:
•
Minimum Delay — The queue is assigned to a strict priority policy, and traffic is assigned to the highest
priority queue.
•
Best Effort — Traffic is assigned to the lowest priority queue
•
Bandwidth Assignments — Bandwidths are assigned by configuring the WRR scheduling scheme.
After packets are assigned to a specific egress queue, Class of Service (CoS) services can be assigned to the
queue. Egress queues are configured with a scheduling scheme by one of the following methods:
•
Strict Priority — Ensures that time-sensitive applications are always forwarded. Strict Priority (SP) allows
the prioritization of mission-critical, time-sensitive traffic over less time-sensitive applications. For example,
under SP, voice over IP (VoIP) traffic can be prioritized so that it is forwarded before FTP or e-mail (SMTP)
traffic.
•
Weighted Round Robin — Ensures that a single application does not dominate the device forwarding
capacity. Weighted Round Robin (WRR) forwards entire queues in a round robin order. All queues can
participate in WRR, except SP queues. SP queues are serviced before WRR queues. If the traffic flow is
minimal, and SP queues do not occupy the whole bandwidth allocated to a port, the WRR queues can share
the bandwidth with the SP queues. This ensures that the remaining bandwidth is distributed according to the
weight ratio.
When configuring QoS for stacking, note that stacking only uses three queues.
This section contains the following topics:
•
Enabling Class of Service (CoS)
•
Configuring CoS Queueing and Scheduling
•
•
•