Office 365 + Lync on-premise integration

Office 365 is the newest Microsoft service offering online versions of Microsoft software in the Cloud and all resources for effective work: business class e-mail on the Exchange Server, SharePoint Portal, Office 2010 and Lync-Online.

Despite the wide variety of functionality available in Lync-Online, Lync as a cloud solution has a number of limitations, which does not allow its full integration with telephony and to replace or extend the functionality of PBX. As a solution of this problem we suggest replacing Lync Online with Lync On-premise fully integrated with Office 365.



Technical specification of implementation

Installation of Lync On-premise is realized on client's servers or in data center (colocation). Public SIP provider connects to the deployed infrastructure and allows connection with PSTN.

At least 3 virtual machines are required for the implementation. If SIP-provider cannot receive SIP-traffic through TCP, it is required to install additional physical or virtual VoIP-gateway.

Requirements for virtual machines (for 20 users):

    • 1st server Windows 2008R2 Standard RAM 1Gb, HDD 40GB, 2 NIC, 2 CPU x64 (1 internet access, 2 VLAN) MS Lync Edge role.
    • 2nd server Windows 2008R2 Standard RAM 1Gb, HDD 40GB, 2 NIC, 2 CPU x64 (1 internet access, 2 VLAN) MS Lync front end and mediation role.
    • 3rd server Windows 2008R2 Standard RAM 2Gb, HDD 40GB, 1 NIC, 2 CPU x64 (VLAN) Active Directory controller.
    • 4th server for virtual VoIP Gateway RAM 512Mb, HDD 15GB, 2 NIC, 1CPU, (internet, LAN) or hardware VoIP gateway for sip trunk with SIP provider.

Virtual machines can be placed on any of the popular hypervisors, VMware ESXi, Microsoft Hyper-V, Citrix XenServer.

For implementation of Lync On-premise, a certificate from a 3rd party certificate authority is essential. For example, Goddady, DigiCert, VeriSign, Commodo.

Requirements to licenses

Plan E4 Office 365 covers all the required clients’ licenses, including extended/updated Enterprise CAL and Plus CAL. Only following server licenses needs to be purchased:

  • Windows 2008R2 Standard – 3 editions;
  • Lync Server 2010 Standard Edition – 1 edition.

Implementation results

Replacement of Lync-online cloud by On-premise allows complete integration of the local telephony with unified communications system. It permits to abandon office PBX in favor of the next-generation platform. Implementation of this solution lets the companies not only to expand their business potential, but also to use the following unique features:

  • Public switched telephone network (PSTN) calling via Lync incoming and outgoing;
  • Anywhere local calls access;
  • Call controls: hold, transfer, forward, simultaneous ring;
  • Voice policies;
  • Response groups, IVR;
  • Call park;
  • Lync conference dial-in from PSTN;
  • Voice mail with Exchange online;
  • Lync IP Phones and Devices.

Any company can combine the benefits of cloud-enabled services and On-Premise technology to get the most effective infrastructure in terms of business requirements.

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