Web Management Guide-R01

Chapter 10 | Quality of Service
Creating QoS Policies
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incremented by one PIR times per second up to BP and the token count Tc is
incremented by one CIR times per second up to BC.
When a packet of size B bytes arrives at time t, the following happens if trTCM is
configured to operate in Color-Blind mode:
■
If Tp(t)-B < 0, the packet is red, else
■
if Tc(t)-B < 0, the packet is yellow and Tp is decremented by B, else
■
the packet is green and both Tp and Tc are decremented by B.
When a packet of size B bytes arrives at time t, the following happens if trTCM is
configured to operate in Color-Aware mode:
■
If the packet has been precolored as red or if Tp(t)-B < 0, the packet is red,
else
■
if the packet has been precolored as yellow or if Tc(t)-B < 0, the packet is
yellow and Tp is decremented by B, else
■
the packet is green and both Tp and Tc are decremented by B.
◆ The trTCM can be used to mark a IP packet stream in a service, where different,
decreasing levels of assurances (either absolute or relative) are given to packets
which are green, yellow, or red. Refer to RFC 2698 for more information on
other aspects of trTCM.
Command Usage
◆ A policy map can contain 512 class statements that can be applied to the same
interface (page 267). Up to 32 policy maps can be configured for ingress ports.
◆ After using the policy map to define packet classification, service tagging, and
bandwidth policing, it must be assigned to a specific interface by a service
policy (page 267) to take effect.
Parameters
These parameters are displayed:
Add
◆ Policy Name – Name of policy map. (Range: 1-32 characters)
◆ Description – A brief description of a policy map. (Range: 1-64 characters)
Add Rule
◆ Policy Name – Name of policy map.
◆ Class Name – Name of a class map that defines a traffic classification upon
which a policy can act.
◆ Action – This attribute is used to set an internal QoS value in hardware for
matching packets. The PHB label is composed of five bits, three bits for per-hop