642-813 Q&A – Prepare infrastructure to support advanced services (16-20)

Section4 – Prepare infrastructure to support advanced services

QUESTION NO: 16
Which statement is true about the Lightweight Access Point Protocol (LWAPP)?
A. The control traffic between the client and the access point is encapsulated with the LWAPP.
B. Data traffic between the client and the access point is encapsulated with LWAPP.
C. Authentication, security, and mobility are handled by the access point.
D. Real-time frame exchange is accomplished within the access point.
Answer: D

Explanation:
When LWAPP was first introduced to the WLAN industry in 2002, it revolutionized the way WLAN deployments were managed with the concept of a “split MAC” the ability to separate the real-time aspects of the 802.11 protocol from most of its management aspects. In particular, real-time frame exchange and certain real-time portions of MAC management are accomplished within the access point, while authentication, security management, and mobility are handled by WLAN controllers.

QUESTION NO: 17
Which set of statements describes the correct order and process of a wireless client associating with a wireless access point?
A. 1. Client sends probe request.
2. Access point sends probe response.
3. Client initiates association.
4. Access point accepts association.
5. Access point adds client MAC address to association table.
B. 1. Client sends probe request.
2. Access point sends probe response.
3. Client initiates association.
4. Access point accepts association.
5. Client adds access point MAC address to association table.
C. 1. Client sends probe request.
2. Access point sends probe response.
3. Access point initiates association.
4. Client accepts association.
5. Access point adds client MAC address to association table.
D. 1. Access point sends probe request .
2. Client sends probe response.
3. Client initiates association.
4. Access point accepts association.
5. Access point adds client MAC address to association table.
E. 1. Access point sends probe request .
2. Client sends probe response.
3. Client initiates association.
4. Access point accepts association.
5. Client adds access point MAC address to association table.
Answer: A

QUESTION NO: 18
Which two statements about a wireless repeater topology are true? (Choose two.)
A. A wireless repeater is an access point that is not connected to the wired LAN.
B. The repeater feature is only available in lightweight access point topologies.
C. The SSID of the root access point must be configured on the repeater access point.
D. This topology requires a 10 – 15 percent overlap between a wired access point and the wireless repeater.
E. This topology requires a 15 – 25 percent overlap between a wired access point and the wireless repeater.
F. To avoid interference, the repeater access point must use a different channel from what the root access point uses.
Answer: AC

QUESTION NO: 19
Which statement is true about IP telephony calls?
A. The voice carrier stream uses H.323 to set up, maintain, and tear down call endpoints.
B. A Voice over IP (VoIP) packet consists of the voice payload, IP header, TCP header, RTP header, and Layer 2 link header.
C. Call control signaling uses Real-Time Transport Protocol (RTP) packets that contain actual voice samples. D. The sum of bandwidth necessary for each major application, including voice, video, and data, should not exceed 75 percent of the total available bandwidth for each link.
Answer: D
Explanation:
Voice over Internet Protocol (VOIP) is probably the most feasible among today’s technologies for data, voice and video integration. VOIP is the technology that uses Internet Protocol to transmit voice conversations over a data network such as an intranet or the Internet.
The multisite IP WAN with distributed call processing has the following design characteristics:
* Cisco CallManager or Cisco CallManager cluster at each location (10,000 users maximum per site)
* Cisco CallManager clusters are confined to a single campus and may not span the WAN
* IP WAN as the primary voice path between sites, with the PSTN as the secondary voice path
* Transparent use of the PSTN if the IP WAN is unavailable
* Cisco IOS gatekeeper for E.164 address resolution
* Cisco IOS gatekeeper for admission control to the IP WAN
* Maximum of 100 sites interconnected across the IP WAN using hub and spoke topologies
* Compressed voice calls supported across the IP WAN
* Single WAN codec supported
* DSP resources for conferencing and WAN transcoding at each site
* Voice mail and unified messaging components at each site
* Minimum bandwidth requirement for voice and data traffic is 56 kbps. For voice, interactive video, and data, the minimum requirement is 768 kbps. In each case, the bandwidth allocated to voice, video, and data should not exceed 75% of the total capacity
* Remote sites can use Cisco IOS as well as gateways based on the Skinny Gateway Protocol

QUESTION NO: 20
Refer to the exhibit. What type of message is transmitted by the lightweight access point (LAP) when it attempts to register to a wireless LAN controller (WLC).

A.The LAP will send Layer 2 Lightweight Access Point Protocol (LWAPP) mode discovery request messages only.
B.The LAP will send Layer 3 Lightweight Access Point Protocol (LWAPP) mode discovery request messages only.
C.The LAP will send both Layer 2 and Layer 3 Lightweight Access Point Protocol (LWAPP) mode discovery request messages at the same time.
D.The LAP will send Layer 2 Lightweight Access Point Protocol (LWAPP) mode discovery request messages. If the attempt fails, the LAP will try Layer 3 LWAPP WLC discovery.
Answer: D