642-642 無料問題集「Cisco Quality of Service (QoS)」

（A）Class-based marking should be implemented because it will be needed for the class-based queuing that will be used on the P router output.

（B）In the DiffServ model, all ingress and egress QoS processing are done at the network edge (for example, PE router), so no input or output QoS policy will be needed on the P to P link.

（C）Because traffic should have already been policed and marked on the upstream ingress PE router, no input QoS policy is needed on the P to P link.

（D）Traffic policing should be implemented to rate-limit the ingress traffic into the P router.

（A）inter-packet arrival rate

（B）interface bandwidth

（C）drop probability denominator

（D）hold-queue limit

（E）hash of the packet headers

（F）congestive discard threshold (CDT)

（A）A Cisco IP Phone is not connected to the fa0/1 switch port.

（B）All incoming DSCP markings are trusted.

（C）All incoming CoS markings are trusted.

（D）DSCP markings from the Cisco IP Phone are trusted.

（A）LLQ/CBWFQ

（B）WFQ

（C）class-based shaping

（D）WRED

（E）class-based policing

（A）router(config)# ip nbar port-map {protocol} [tcp|udp] {port-number} {port-number} ....

（B）router(config-cmap)# match protocol {protocol-name}

（C）router(config-if)# ip nbar protocol-discovery

（D）router(config)# ip nbar pdlm {pdlm-file}

（A）Ensure voice traffic is serviced by a weighted fair queue.

（B）Only a reasonable number of applications should be classified into the mission-critical traffic class.

（C）NBAR is used at the high speed core layer to discover and classify network applications.

（D）Catalyst switches should use weighted round robin (WRR) queuing giving the voice traffic the highest priority.

（E）Traffic classification and marking is performed as close to the traffic source as possible.

（F）Traffic classification and marking is performed at the high speed core layer.

（A）The class-map class1 command will set the qos-group value to 4 for all IP packets.

（B）The configuration is invalid since it refers to a class map within a different class.

（C）Regardless of destination IP address, all traffic sent to Mac address 1.2.3 will be subject to policing

（D）Any IP packet will be subject to policing.

（E）All traffic from a server with the IP address of 147.23.54.21 will be subject to policing.

（F）Only those packets which satisfy all of the matches in class1 and class2 will be subject to policing.

（A）the use of nested class-maps with class-based marking

（B）the use of class-based WRED within a CBWFQ class queue

（C）the use of both the bandwidth and shape statements within a CBWFQ class queue

（D）the use of CBWFQ inside class-based shaping

（E）the use of a strict priority-class queue within CBWFQ