You are planning the Peer-to-Peer (P2P) audio bandwidth requirements for the Berlin wide area network
(WAN) connection.
You need to calculate the bandwidth usage network impact of P2P audio calls between Berlin and
Moscow.
What is the minimum bandwidth in megabits per second (Mbps) required for P2P calls between Berlin and
Moscow?
A. 9.1 Mbps
B. 8.7 Mbps
C. 6.1 Mbps
D. 7.8 Mbps
Answer: B
Explanation:
Explanation/Reference:
Explanation:
Silk Wideband is used for P2P audio. 44.3 kbps x 196 maximum users = 8.7 Mbps.
Case Study
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Overview
Trey Research is a global marketing research organization that has a main office in Moscow and branch
offices in Los Angeles, London, Berlin, Copenhagen, and Jakarta.
The number of users per office is shown below:
Existing systems and telephones
The company has existing IP-PBX systems that are reaching end of life. They use an automatic call
distribution (ACD) system for their help desk. This system provides interactive voice response options to
users so that they can choose the location for support. This system is also reaching end of life.
The Copenhagen office uses a call group pickup solution that runs on an existing IP-PBX system. All users
with the exception of users in Copenhagen have Direct Inward Dialing (DID) numbers.
Trey Research has Skype for Business Enterprise pools in the Moscow, London, and Berlin offices,
respectively. They run a Unified Communications Managed API (UCMA) based application in a trusted
application pool.
All users in Trey Research are using Aries phones. Users authenticate by using PIN codes.
Quarterly global town hall meetings
Executives conduct global town hall meetings each quarter. Each meeting occurs in a different office.
Employees attend the global town hall meetings in meeting rooms which are equipped with full high
definition (HD) screens for video. Ten percent of the employees attend the audio portion of the global town
hall meetings from their desk.
Trey Research plans to implement Skype for Business Enterprise Voice across the company to replace the
existing IP-PBX systems.
Bandwidth Calculation Values
You must use the following typical bandwidth values to determine the bandwidth requirements in kilobits
per second (Kbps) for the solution:
Video resolution bandwidth:
Audio codec bandwidth:
Requirements
You have the following requirements:
General
You must reduce international long distance calling costs, and lower support and administration costs
for the IP-PBX and ACD solutions.
You must implement voice survivability for all the sites in case of a wide area network (WAN) link
failure.
Where possible, you must optimize media paths.
The solution must be resilient to the failure of mediation server pools.
The maximum concurrent peer-to-peer connections between Moscow and Berlin will be 196.
Response groups must be managed by dedicated response group administrators.
Gateways
Existing gateways do not support the REFER method. You must use the existing gateways with Skype
for Business to provide PSTN connectivity.
In the event of a failure of both gateways at any office, all international calls from that office must route
through the Moscow gateways.
Outbound calls
All calls placed to Russia from any office must route through the Moscow gateways.
Germany experiences high public switched telephone network (PSTN) call volume. All calls for
Germany must breakout from Berlin in the event of Mediation Server pool failure in Berlin.
All PSTN calls to Germany must use Berlin gateways in the event of Mediation Server pool failure in
Berlin.
Enterprise Voice
You test the Enterprise Voice solution with users in the Copenhagen office. During testing, users reported
audio call issues related to the Call Admission Control (CAC) configuration. The relevant portion of the
current configuration is shown in the Table below:
You create the following policies:
Problem Statements
Two users who recently joined the company's finance department report that they are not able to use their
Aries phones even when they tether the phone to their computer.