Download New Latest (May) Cisco 400-051 Actual Tests 111-120

Ensurepass

 

Q111  (Topic 5)

 

Which statement describes the key security service that is provided by the TLS Proxy function on a Cisco ASA appliance?

 

 

A.It provides interworking to ensure that external IP phone traffic is encrypted, even if the rest of the system is unencrypted.

 

B.It only applies to encrypted voice calls where both parties utilize encryption.

C.It manipulates the call signaling to ensure that all media is routed via the adaptive security appliance.

 

D.It enables internal phones to communicate with external phones without encryption.

E.It protects Cisco Unified Communications Manager from rogue soft clients and attackers on the data VLAN.

 

Answer: B

Explanation: TLS Proxy is typically deployed in front of Cisco Unified Communications Manager and other unified communications application servers that utilize media encryption. TLS Proxy is not designed to provide remote-access encryption services for remote phones or client endpoints. Other solutions such as Cisco ASA Phone Proxy or IP Security/Secure Sockets Layer (IPsec/SSL) VPN services are more appropriate.TLS Proxy is not designed to provide a secure campus soft phone solution where the requirement is to provide secure data to phone VLAN traversal or for proxying connections to Cisco Unified Communications Manager.

 

 

 

Q112  (Topic 5)

 

Which entity signs a Cisco IP phone LSC?

 

 

A.Godaddy.com Enrollment Server

 

B.Manufacturer Certificate Authority

 

C.Registration Authority

 

D.Certificate Authority Proxy Function

 

E.Cisco Certificate Authority

 

Answer: D

Explanation: By default, LSC certificates are not installed on Cisco IP phones. Cisco IP phones that are required to use LSC certificates must be provisioned to allow TLS transactions before deployment in the field. LSC certificates can be provisioned to the Cisco IP phones through the Certificate Authority Proxy Function (CAPF) process. This process is completed using TLS and USB tokens coupled with the CTL client. Moreover, the Cisco ASA Phone Proxy feature can serve LSC certificates to the Cisco IP phones. Cisco IP phones will only work with the Cisco ASA Phone Proxy and will not establish secure connectivity with the Cisco Unified Communications Manager.

 

Q113  (Topic 5)

 

In Cisco IOS routers that use low latency queuing, which algorithm is used to presort traffic going into the default queue?

 

 

A.first-in, first-out

 

B.last-in, first-out

 

C.weighted round robin

 

D.fair queuing

 

E.random processing

 

Answer: D

Explanation: WFQ is a flow-based queuing algorithm used in Quality of Service (QoS) that does two things simultaneously: It schedules interactive traffic to the front of the queue to reduce response time, and it fairly shares the remaining bandwidth between high bandwidth flows. A stream of packets within a single session of a single application is known as flow or converstion. WFQ is a flow-based method that sends packets over the network and ensures packet transmission efficiency which is critical to the interactive traffic.

 

 

 

This method automatically stabilizes network congestion between individual packet transmission flows.

 

Q114  (Topic 5)

 

Assume 20 bytes of voice payload, 6 bytes for the Layer 2 header, 1 byte for the end-of- frame flag, and the IP, UDP, and RTP headers are compressed to 2 bytes, how much bandwidth should be allocated to the strict priority queue for six VoIP calls that use a G.729 codec over a multilink PPP link with cRTP enabled?

 

 

A.80.4 kb/s

 

B.91.2 kb/s

 

C.78.4 kb/s

 

D.69.6 kb/s

 

E.62.4 kb/s

 

Answer: D

Explanation: Voice payloads are encapsulated by RTP, then by UDP, then by IP. A Layer 2 header of the correct format is applied; the type obviously depends on the link technology in use by each router interface: A single voice call generates two one-way RTP/UDP/IP packet streams. UDP provides multiplexing and checksum capability; RTP provides payload identification, timestamps, and sequence numbering.

 

Q115  (Topic 5)

 

Assume a 30-millisecond voice payload, 6 bytes for the Layer 2 header, 1 byte for the end- of-frame flag, and the IP, UDP, and RTP headers are compressed to 2 bytes, how much bandwidth should be allocated to the strict priority queue for eight VoIP calls that use a G.729 codec over a multilink PPP link with cRTP enabled?

 

 

A.121.6 kb/s

 

B.92.8 kb/s

 

C.88.4 kb/s

 

D.83.2 kb/s

 

 

 

E.78.4 kb/s

 

Answer: D

Reference:

http://www.cisco.com/en/US/tech/tk652/tk698/technologies_tech_note09186a0080094ae2.

shtml

 

Q116  (Topic 5)

 

The iLBC codec operates at 38 bytes per sample per 20-millisecond interval. What is its codec bit rate in kilobits per second?

 

 

A.6.3

 

B.13.3

 

C.15.2

 

D.16

 

E.24

 

Answer: C

Explanation: Explanation; The internet Low Bit Rate Codec (iLBC) is designed for narrow band speech and results in a payload bit rate of 13.33 kbits per second for 30-millisecond (ms) frames and 15.20 kbits per second for 20 ms frames. When the codec operates at block lengths of 20 ms, it produces 304 bits per block, which is packetized as defined in RFC 3952. Similarly, for block lengths of 30 ms it produces 400 bits per block, which is packetized as defined in RFC 3952.The iLBC has built-in error correction functionality to provide better performan
ce in networks with higher packet loss

 

Q117  (Topic 5)

 

To which QoS tool category does compressed RTP belong?

 

 

A.classification

 

B.marking

 

C.link efficiency

 

D.queuing

 

 

 

E.prioritization

 

Answer: C

Explanation: LLQ is a feature that provides a strict PQ to CBWFQ. LLQ enables a single strict PQ within CBWFQ at the class level. With LLQ, delay-sensitive data (in the PQ) is dequeued and sent first. In a VoIP with LLQ implementation, voice traffic is placed in the strict PQ.

 

Q118  (Topic 5)

 

How are queues serviced in Cisco IOS routers with the CBWFQ algorithm?

 

 

A.first-in, first-out

 

B.weighted round robin based on assigned bandwidth

C.strict priority based on assigned priority

 

D.last-in, first-out

 

E.weighted round robin based on assigned priority

 

Answer: B

Explanation: Class Based Weighted Fair queuing is an advanced form of WFQ that supports user defined traffic classes i.e. one can define traffic classes based on match criteria like protocols, access control lists (ACLs), and input interfaces. A flow satisfying the match criteria for a class contributes the traffic for that particular defined class. A queue is allocated for each class, and the traffic belonging to that class is directed to the queue for that class.

 

Topic 6, Cisco Unity Connection

 

Q119  (Topic 6)

 

Which statement about accessing secure Cisco Unity Connection voice messages in an Exchange mailbox in a Single Inbox deployment is true?

 

 

A.Users can listen to a secure voice message if they use the Outlook email client.

 

 

 

B.Users can listen to a secure voice message if they use the Outlook email client with the ViewMail add-in.

 

C.Users can listen to a secure voice message with email clients other than Outlook if they have installed the ViewMail add-in.

 

D.Users cannot listen to a secure message in Exchange because it is not supported in Single Inbox.

 

E.Secure voice messages are stored on the Cisco Unity Connection server and the Exchange server.

 

Answer: B

Explanation: Users can listen to a secure voice message if they use the Outlook email client with the ViewMail add-in. Because in this integration outlook integrate with unity as secre smap client .

 

Q120  (Topic 6)

 

Which Cisco Unity Connection call handler greeting, when enabled, overrides all other greetings?

 

 

A.holiday

 

B.closed

 

C.internal

 

D.busy

 

E.alternate

 

Answer: E

Explanation: An Alternate greeting might be enabled to override the Standard Greeting during

certain times. Because it is a personal greeting used for specific purpose.

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