Web Management Guide-R05

Chapter 10 | Quality of Service
Creating QoS Policies
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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
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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 1024 class statements that can be applied to the
same interface (page 261). 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 261) 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. A policy map can contain up to 200 class maps.
◆ 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
behavior, and two bits for the color scheme used to control queue congestion
with the srTCM and trTCM metering functions.
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Set CoS – Configures the service provided to ingress traffic by setting an
internal CoS value for a matching packet (as specified in rule settings for a
class map). (Range: 0-7)
See Table 17, “Default Mapping of CoS/CFI to Internal PHB/Drop
Precedence,” on page 242).
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Set PHB – Configures the service provided to ingress traffic by setting the
internal per-hop behavior for a matching packet (as specified in rule
settings for a class map). (Range: 0-7)