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Topic 3, Contoso Ltd
Background
Contoso, Ltd. is a Canadian business law firm that currently employs 300 people. Contoso operates a main office in Vancouver that houses 250 employees and a branch office in Seattle that houses 50 employees. All Contoso users are Lync-enabled.
Contoso plans to introduce a remote disaster recovery data center to host remote replicas of key services, including Active Directory, Lync, Exchange, and files and legal software, Contoso is launching a hybrid configuration of Office 365 to validate the cloud-based Exchange Online service.
Contoso also plans to acquire a small law firm in Vancouver called Litware, Inc., which has 80 employees. Litware currently uses a 10-megabit per second (Mbps) Internet connection. Half of Litware employees will use Lync services. All Lync-enabled users in Litware will use Instant Messaging only. Currently, Instant Messaging concurrent usage at Litware is 50 percent during peak hours.
There is a possibility that Contoso will make two more acquisitions during the next three years. Vancouver and Seattle employees have submitted support tickets to report poor quality of outbound Lync calls to external users. A user activity report collected by the help desk department is shown in the User Activity Report section.
There is a concern that in the future, the volume of Lync traffic may reach up to 50 percent of the current bandwidth available in the Vancouver office.
User Activity Report


Existing Environment
The core portion of the infrastructure is located in the Vancouver data center, although the Seattle data center also has two servers (listed below) to provide redundancy of Active Directory and data services. The following services and applications comprise Contoso's infrastructure in Vancouver and Seattle:
Vancouver Data Center

Seattle Data Center

An overview of the network infrastructure of Vancouver and Seattle data centers is shown in the exhibit. (Click the Exhibit button.)

All users in the Vancouver and Seattle offices use the Microsoft Windows 8 Enterprise operating system and Lync phones that are enabled for Enterprise voice. Contoso expects to see a growing number of remote users. They anticipate that up to 20 percent of users in Vancouver might work remotely.
Contoso has defined a team of 35 users who will participate in a pilot deployment of the Office 365 hybrid configuration.
The offices in Vancouver and Seattle are using 5-Mbps Internet connections. Contoso has a site-to-site VPN between the Vancouver office and the Seattle office. All external outbound calls from the Vancouver and Seattle offices are routed outside through the office in Vancouver.
Business Requirements
Contoso needs to review the existing network topology as well as the Lync 2013 infrastructure to ensure that network capacity is sufficient to accommodate the Litware, Inc. Lync users in the future.
Contoso expects to see up to 85 percent of simultaneous instant messaging and 25 percent of public switched telephone network (PSTN) calls during business hours. All existing issues that relate to poor quality of outbound Lync calls need to be addressed as well.
Contoso wants to ensure the following: - Current network bandwidth allocated to the Vancouver office is sufficient to sustain the future volume of Lync traffic and guarantee high quality of Lync calls. - Volume of Lync traffic does not exceed 25 percent of the WAN bandwidth.
Contoso plans to redesign the existing site-to-site VPN solution between the Vancouver and Seattle offices to implement a robust and reliable WAN solution with end-to-end support of Quality of Service (QoS).
The recommended design solution needs to eliminate the possibility of WAN oversubscription by Lync traffic.
The proposed Lync 2013 solution needs to be: - Scalable to accommodate the company's future acquisitions. - Readily available for Vancouver and Seattle users.
In case of a disaster, a manual switchover of Lync services to the disaster recovery datacenter should be available.
Technical Requirements
All Session Initiation Protocol traffic (SIP) traffic must be encrypted.
All external Lync 2013 services must be protected by a firewall.
A commercial third-party certificate must be used on the external interface of Lync 2013
Edge servers.
The Role-Based Access Control (RBAC) model will be implemented to delegate basic
administrative tasks to the Lync help desk team.
All maintenance of Lync servers must be performed outside of business hours.
The proposed architecture solution must support interoperability between Lync 2013 and
Exchange 2013.
The Microsoft Lync 2013 Bandwidth Calculator must be used to analyze Lync traffic. The
QoS end-to-end support needs to be implemented.
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You need to determine which connection will be most affected by the Office 365 users.
Which two connections should you select? (Each correct answer presents part of the solution. Choose two.)

• A. The site-to-site virtual private network (VPN) between the Vancouver and Seattle offices.
• B. The internet connection at the Seattle office.
• C. The PSTN connection at the Vancouver office.
• D. The internet connection at the Vancouver office.
• E. The PSTN connection at the Seattle office.

You need to identify the metric that is causing poor quality in Lync calls by analyzing the user activity report collected by the help desk department.
Which metric should you choose?

• A. packet loss
• B. jitter
• C. round trip
• D. burst gap duration

You need to ensure that wireless users in the main office stay associated with the most powerful wireless access point (WAP) available when they are roaming.
What should you do?

• A. Decrease IP Dynamic Host Configuration Protocol (DHCP) lease timeout on WAPs.
• B. Configure fast roaming.
• C. Configure all WAPs on the same channel.
• D. Disable lower data rates on WAPs.

HOTSPOT
You need to modify the relevant portion of the Persona configuration in the Lync Bandwidth Calculator to estimate the planned volume of Lync traffic for the Contoso office in Vancouver.
Which options should you select? (To answer, select the appropriate value in each drop-down menu in the Lync Bandwidth Calculator.)