Default Qos Settings; Qos Configuration Guidelines - Nortel business policy switch 2000 User Manual

306 Chapter 4 Policy-enabled networks
The filter groups are associated with policies, and policies are organized into a
hierarchy. The policy with the highest precedence is evaluated first. The filters and
filter groups are associated with interface groups, in that packets from a specific
port will have the same filters as all others in the particular interface group (role
combination).
Meters, operating at ingress, keep the sorted packets within certain parameters.
You configure a committed rate of traffic, allowing a certain size for a temporary
burst, as In-Profile traffic. All other traffic is configured as Out-of-Profile traffic.
If you choose not to meter the flow, you do not configure meters.
Shaping specifies a maximum transmission rate over a given period, as well as a
burst size that allows a traffic flow to briefly exceed the shaping rate. You can also
specify, within a specified range, the number of packets that can be held prior to
transmission until the necessary bandwidth is available at egress. Some packets
may be dropped if buffers are completely used. If you choose not to shape the
flow, you do not configure shapers.
Actions determine how the traffic is treated.
The overall total of all the interacting QoS factors on a group of packets is a
policy. You configure policies that monitor the characteristics of the traffic and
perform a controlling action on the traffic when certain user-defined
characteristics are matched.

Default QoS settings

The Business Policy Switch is shipped with limited default QoS information.
Defaults include a default interface group, default user priority-to-queue
mappings for each queue set, and default DSCP-to-user priority mappings.

QoS configuration guidelines

You can install filters that will act on traffic destined for the switch itself, such as
ICMP Echo Requests (ping) and SNMP messages. If the associated action is to
drop the traffic, you can lock yourself out of the switch.
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