QUESTION 1
With unmanaged CE routers, at which point in the service provider network is the QoS trust boundary, and what is required at the trust boundary? Cisco 642-887 dumps Questions
A. between the CE and PE router and mapping of the customer traffic classes into the service provider traffic classes at the PE router ingress
B. between the CE and PE router and trusting the QoS markings from the CE router and applying the required QoS mechanisms based on the customer QoS markings
C. between the PE and the P router and mapping of the customer traffic classes into the service provider traffic classes at the P router ingress
D. between the PE and P router and trusting the QoS markings from the CE router and applying the required QoS mechanisms based on the customer QoS markings
E. between the customer network and the CE router ingress and applying the required egress QoS policy on the CE router
Correct Answer: A
QUESTION 2
On the Cisco IOS XR, when using the match protocol command within a class-map to classify traffic, you noticed that the match protocol option on the Cisco IOS XR shows much fewer protocol options than on the Cisco IOS or IOS XE, like there is no option such as the match protocol yahoo-messenger command on the Cisco IOS XR. Why is this?
A. because the Cisco IOS XR router does not have the correct software packages installed
B. because when defining the class-map, the class-map type should be set to type inspect: class- map type inspect class-map-name command
C. because NBAR is not supported on the Cisco IOS XR
D. because flexible packet matching has not been enabled on the Cisco IOS XR router
Correct Answer: C
QUESTION 3
Within the service provider core network, which two QoS mechanisms are typically deployed on the P routers? (Choose two.) 642-887 dumps
A. LLQ
B. traffic policing and remarking
C. WRED
D. traffic shaping
E. traffic classification and markings
F. link fragmentation and interleaving
Correct Answer: AC
QUESTION 4
Which three steps are required to configure QPPB on Cisco IOS XR routers? (Choose three.)
A. Apply a QPPB route policy to the BGP process using the table-policy command
B. Apply a QPPB route policy to the BGP neighbor using the route-policy command
C. Define a QPPB route policy to match the customer routes, then set the IP precedence or qos- group
D. Define a QPPB route policy to match the customer IP precedence or qos-group markings, then set the BGP community
E. Enable QPPB on an interface using the ipv4 bgp policy propagation input ip-precedence|qos- group destination|source command
F. Enable QPPB on an interface using the ipv4 bgp policy propagation output ip-precedence|qos- group destination|source command
Correct Answer: ACE
Explanation:
QoS Policy Propagation via BGP (QPPB), is a mechanism that allows propagation of quality of service (QoS) policy and classification by the sending party based on access lists, community lists and autonomous system paths in the Border Gateway Protocol (BGP), thus helping to classify based on destination instead of source address.
QUESTION 5
The Cisco IOS and IOS XE qos pre-classify command allows which kind of packet classification on IP packets that are encapsulated with GRE and IPsec?
A. allows for packets to be classified based on the ToS byte values before packet encryption
B. allows for packets to be classified based on the ToS byte values after packet encryption
C. allows for packets to be classified based on the packet payload before packet encryption
D. allows for packets to be classified based on the packet payload after packet encryption
E. allows for packets to be classified based on the packet header parameters other than the ToS byte values after packet encryption
Correct Answer: E
QUESTION 6
Which are typical class-based marking policies that are implemented on service provider IP NGN PE routers? 642-887 dumps
A. On the PE ingress, classify the customer traffic and then mark with qos-group. On the PE egress, classify based on the qos-group and then mark with mpls exp.
B. On the PE ingress, classify the customer traffic and then mark with mpls exp. On the PE egress, classify based on the mpls exp and then mark with qos-group.
C. On the PE ingress, trust the customer QoS markings. On the PE egress, classify based on the customer QoS markings and then mark with qos-group.
D. On the PE ingress, trust the customer QoS markings. On the PE egress, classify based on the customer QoS markings and then mark with mpls exp.
Correct Answer: A
QUESTION 7
Which item is not available to be used for QoS classification in Cisco IOS XR?
A. MAC SA
B. protocol
C. inner EXP
D. discard-class
E. QoS-group
F. VLAN
Correct Answer: C
QUESTION 8
Which statement is correct regarding the default MPLS TTL behavior?
A. When an ingress edge LSR receives an IP packet, it will decrement the IP TTL field by 1; then it will set the MPLS Label TTL field to 255.
B. When an ingress edge LSR receives an IP packet, it will decrement the IP TTL field by 1; then it will copy the decremented IP TTL field into the MPLS Label TTL field.
C. When an ingress edge LSR receives an IP packet, it will just copy the IP TTL field into the MPLS Label TTL field.
D. When an ingress edge LSR receives an IP packet, it will copy the IP TTL field into the MPLS Label TTL field first; then it will only decrement the MPLS Label TTL field by 1.
E. When an ingress edge LSR receives an IP packet, it will copy the IP TTL field into the MPLS Label TTL field first; then it will only decrement the IP TTL field by 1.
Correct Answer: B
QUESTION 9
Which three statements are correct regarding ping mpls command operations? (Choose three.)
A. MPLS OAM has to be enabled on the router using the mpls oam command.
B. They use a 127/8 address as the destination address in the MPLS echo request packet.
C. They use ICMP echo request and ICMP echo reply packets.
D. They are used to test for a broken LSP.
E. If there is a broken LSP, instead of using label switching, the packet can still be forwarded based on the destination IP address in the mpls ping echo request packet.
Correct Answer: ABD
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