This section describes the environment prior to deployment of Office Communications Server 2007 R2 Enterprise Voice.
Litware before migration to Office Communications Server 2007 R2
Litware has two sites. The main site is located in Redmond, Washington, USA (country code 1, area code 425), and the other site is located in Cologne, Germany (country code 49, area code 221). The US site has 250 users, and the Germany site consists of 80 users.
Litware has a Windows Server 2003–based Active Directory with one forest and one domain, Litware.com. Litware.com has only one Active Directory site, and the domain functional level is native Windows Server 2003. Users in Germany access all resources across a well-connected VPN.
The Litware datacenter is located in Redmond, Washington, where domain controllers, Exchange Server, and other business-critical server roles are deployed.
The Litware phone number in the US is +1 425 555 0100-0399. Extensions from 100 to 399 compose the entire number range that belongs to Litware. This also means that numbers of the form +1425 555 04xx will belong to another company. This range of numbers is an important block of information that needs to be anticipated in the dial plan configuration. The main phone number of Litware in the US is +1 425 555 0333.
The user population on the Redmond site is optimal for an Office Communications Server 2007 R2 Enterprise Voice deployment: about 90% of all users have PC workstations with a PBX phone from a TDM (Time Division Multiplexing) PBX right next to their PCs. None of the users function as part of a call center configuration. The Redmond site has two workspaces that operate as attendant consoles that answer calls on the corporate main line.
There are two primary rate interface (PRI) connections to the public switched telephone network (PSTN); each is a T1 connection with 23 concurrent channels. Each channel can be used for inbound and outbound calls. There are a total of 46 channels to the PSTN, which is sufficient for the 250 users on the Redmond site because those users have a standard office telephone usage and are not part of a call center. Erlang B calculators to calculate the number of concurrent connections required to accommodate Busy Hour Traffic can be found in various places on the Internet.
Alongside the office workspace phones, additional devices are connected to the PBX. We assume that there are about eight analog standalone fax machines, one elevator phone, and 20 additional wall-mounted analog phones connected to the PBX.
Figure: Litware Redmond Site
Cologne, Germany site
Litware has no datacenter in Cologne, Germany, but it has facilities that are capable of hosting servers as needed. A wide area network (WAN) connection between the Cologne and Redmond sites allows Cologne users to use the Redmond datacenter infrastructure for their daily needs.
The Litware phone number range in Germany is +49 221 801xx. Litware has the complete 2 digit extension range from 10 to 99. Extension 0 is generally reserved as the company’s main phone number, and the German attendant console operator will answer all incoming calls on this main number. The corporate main phone number is +49 221 801-0. In Germany, the length of phone numbers is not necessarily fixed within area codes or local subscriber numbers. This variability in length is important for the dial plan configuration.
The user population on the Cologne site is also optimal for an Office Communications Server 2007 R2 Enterprise Voice deployment, because about 90% of all users have PC workstations with a PBX phone from a TDM PBX next to their PCs. None of the users operate as part of a call center configuration. There is one workstation that operates as an attendant console and that answer calls on the corporate main line.
The Cologne site has one E1 PRI connection to the PSTN with 30 concurrent channels. Each channel can be used for inbound and outbound calls. 30 concurrent channels are sufficient to accommodate peak hour traffic, because not more than 9 (10%) users are concurrently in PSTN calls.
In addition to the office workspace phones, a few additional devices are connected to the Cologne PBX. To keep this example simple, we assume that there is only one analog standalone fax machine and one additional wall-mounted analog lobby phone connected to the PBX.
Figure: Litware Cologne Site
Litware has not linked their two PBX nodes together, and so they should be considered standalone systems.