86 Planning and engineering• An understanding of the coexistence interactions. For more information,see "LCS 2005 and OCS 2007 coexistence" (page 82).• An understanding of CS 1000, Signaling Server, and networks.• An understanding of the user migration process.Determine your deployment optionsThere are two deployment options depending on whether you are migratinga small or large client base.For a small client base, Office Communicator client users can be migratedfrom LCS to OCS inside a set maintenance window. No extra servers arerequired.For a large client base, Office Communicator client users need to bemigrated over multiple maintenance windows using a phased approach.The following choices must be made:1. If using one SIP CTI FE Signaling Server• Only LCS users have RCCOR• OCS users have RCC2. If deploying an additional SIP CTI FE Signaling Server• RCC is supported for both LCS and OCS. One Signaling Server forLCS RCC and the other for OCS RCCATTENTIONBefore migrating to Office Communications Server 2007, existing LiveCommunications Servers must have Live Communications Server 2005 SP1installed.Migration processThe following table breaks down the migration process using a phased,outside-in approach and defines the impact for the user at each phase.Table 19User experiencePhase Description User experience1. Upgrade your perimeternetwork.Introduce a new OfficeCommunications Server (OCS)2007 Access Edge Serversand Directors into your LiveCommunications Server (LCS)2005 SP1 environment.No changes. Users continueto use the Microsoft OfficeCommunicator (OC) 2005 clientand have the same IM andpresence functionality.Nortel Communication Server 1000Nortel Converged Office Fundamentals — Microsoft Office Communications Server 2007NN43001-121 01.03 StandardRelease 5.0 30 April 2008Copyright © 2005–2008, Nortel Networks.
