what type of marker is achieved?

Refer to the exhibit.

Based on this configuration, what type of marker is achieved?

A.
Single-rate, two-color marker V

B.
Three-rate, two-color marker

C.
Two-rate, three-color marker

D.
Single-rate, three-color marker

Explanation:
Networks police traffic by limiting the input or output transmission rate of a class of traffic based on
userdefined criteria. Policing traffic allows you to control the maximum rate of traffic sent or
received on an interface and to partition a network into multiple priority levels or class of service
(CoS).
The Two-Rate Policer performs the following functions:
Limits the input or output transmission rate of a class of traffic based on user-defined criteria.
Marks packets by setting the IP precedence value, IP differentiated services code point (DSCP)
value, Multiprotocol Label Switching (MPLS) experimental value, Quality of Service (QoS) group,
ATM Cell Loss Priority (CLP) bit, and the Frame Relay Discard Eligibility (DE) bit.
With the Two-Rate Policer, you can enforce traffic policing according to two separate
rates—committed information rate (CIR) and peak information rate (PIR). You can specify the use
of these two rates, along with their corresponding values, by using two keywords, cir and pir, of the
police command. For more information about the police command, see the “Command Reference”
section of this document. The Two-Rate Policer manages the maximum rate of traffic through a
token bucket algorithm. The token bucket algorithm can use the user-configured values to
determine the maximum rate of traffic allowed on an interface at a given moment in time. The
token bucket algorithm is affected by all traffic entering or leaving the interface (depending on the
location of the interface on which the Two-Rate Policer is configured) and is useful in managing
network bandwidth in cases where several large packets are sent in the same traffic stream.
Configuration Tasks
See the following sections for configuration tasks for the Two-Rate Policer feature. Each task in
the list is identified as either required or optional.
Configuring the Two-Rate Policer (required)

Verifying the Two-Rate Policer Configuration (optional)
Configuring the Two-Rate Policer
The Two-Rate Policer is configured in the service policy. To configure the Two-Rate Policer, use
the following command in policy-map class configuration mode:

Although not required for configuring the Two-Rate Policer, the command syntax of the police
command also allows you to specify the action to be taken on a packet when you enable an
optional action argument. The resulting action corresponding to the keyword choices are listed in
Table 1.
Table 1 police Command Action Keywords

Related Documents
Cisco IOS Quality of Service Solutions Configuration Guide, Release 12.2
Cisco IOS Quality of Service Solutions Command Reference, Release 12.2
RFC 2698, A Two Rate Three Color Marker

The two-rate policer is often configured on interfaces at the edge of a network to limit the rate of
traffic entering or leaving the network. In addition to rate-limiting traffic, the policer’s three-color
marker can mark packets according to whether the packet conforms (green), exceeds (yellow), or
violates (red) a specified rate. You decide the actions you want the router to take for conforming,
exceeding, and violating traffic. For example, you can configure conforming packets to be sent,
exceeding packets to be sent with a decreased priority, and violating packets to be dropped. In
most common configurations, traffic that conforms is sent and traffic that exceeds is sent with
decreased priority or is dropped. You can change these actions according to your network needs.
With packet marking, you can partition your network into multiple priority levels or classes of
service (CoS). For example, you can configure the two-rate three-color marker to do the following:
Assign packets to a QoS group, which the router then uses to determine how to prioritize packets
within the router. Set the IP precedence level, IP DSCP value, or the MPLS experimental value of
packets entering the network. Networking devices within your network can then use this setting to
determine how to treat the traffic. For example, a weighted random early detection (WRED) drop
policy can use the IP precedence value to determine the drop probability of a packet.
Set the ATM cell loss priority (CLP) bit in ATM cells. The ATM CLP bit is used to prioritize packets
in ATM networks and is set to either 0 or 1. During congestion, the router discards cells with a CLP
bit setting of 1 before it discards cells with a CLP bit setting of 0.
The three-color marker distinguishes between the nonconforming traffic that occasionally bursts a
certain number of bytes more than the CIR and violating traffic that continually violates the PIR
allowance. Applications can utilize the three-color marker to provide three service levels:
guaranteed, best effort, and deny. The threecolor marker is useful in marking packets in a packet
stream with different, decreasing levels of assurances (either absolute or relative). For example, a
service might discard all red packets because they exceed both the committed and excess burst
sizes, forward yellow packets as best effort, and forward green packets with a low drop probability.

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