Refer to the exhibit. As a network administrator, you have configured a dual-rate, dual-bucket
policer in accordance with RFC 2698 on the serial interface of you router, connecting to your
provider. The SLA with your provider states that you should only send AF31 (limited to 150 kb/s),
AF32 (limited to 50 kb/s)and AF33 (best effort). Your service provider claims you are not
conforming to the SLA. Which two things are wrong with this configuration? (Choose two.)
A.
The configuration of a service policy on half-duplex Ethernet interfaces is not supported.
B.
The class class-default sub-command of the policy-map limit command should be set to the
DSCP default.
C.
The violate action is wrong.
D.
This policer configuration is not implementing RFC 2698 dual-bucket, dual-rate.
E.
The policer is configured in the wrong class.
Explanation:
All of the policing is supposed to be applied to AF31 & AF32 but instead it is applied to AF33
Feature Overview
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.
The token bucket algorithm provides users with three actions for each packet: a conform action,
an exceed action, and an optional violate action. Traffic entering the interface with Two-Rate
Policer configured is placed in to one of these categories. Within these three categories, users can
decide packet treatments. For instance, packets that conform can be configured to be sent,
packets that exceed can be configured to be sent with a decreased priority, and packets that
violate can be configured to be dropped.
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 the most common configurations, traffic that conforms is
sent and traffic that exceeds is sent with a decreased priority or is dropped. Users can change
these configuration options to suit their network needs.Note Additionally, the Two-Rate Policer enables you to implement Differentiated Services
(DiffServ) Assured Forwarding (AF) Per-Hop Behavior (PHB) traffic conditioning. For more
information about DiffServ, refer to the
“Implementing DiffServ for End-to-End Quality of Service” chapter of the Cisco IOS Quality of
Service Solutions
Configuration Guide, Release 12.2.
Police To configure traffic policing, use the police command in policy-map class configuration
mode. To remove traffic policing from the configuration, use the no form of this command.
police {cir cir} [bc conform-burst] {pir pir} [be peak-burst] [conform-action action[exceed-action
action [violateaction action]]]
no police {cir cir} [bc conform-burst] {pir pir} [be peak-burst] [conform-action action [exceed-action
action[violate-action action]]]
Syntax Description
http://www.cisco.com/en/US/docs/ios/12_2t/12_2t4/feature/guide/ft2RTplc.html#wp1015327
