Acceptable Uptime (%)Downtime Per dayDowntime Per monthDowntime Per year minutes36 hours18.26 days minutes7 hours3.65 days seconds43 minutes8.77 hours seconds4 minutes52.60 minutes seconds26 seconds5.26 minutes

Multiple Front Ends presented to users by DNS and HW load balancing Local instance of runtime data (RTClocal) Implementation of Windows Fabric and Routing Group logic Multiple Back End servers available to pool Less reliance on Back End allows for continuation of services in failure Implementation of SQL Mirroring allows for shared data, not storage

User Group 1 User Group 2 Group 1 Group 3 Fabric node Group 2 Fabric node Group 1 Fabric node Group 3 Fabric node Group 3 Fabric node Group 1 Fabric node Group 2 13 Windows Fabric is installed on each Front End Users are provisioned to a pool in Routing Groups Via fabric, three replicas of routing group data are kept updated

Seamlessly failover within Pool No data loss incurred Primary FEBackup1 FEBackup2 FEBackend DB Deployment of multiple Front End servers allows for automated failover where clients are redirected Each Front End has a potential for two backup Front Ends, so a failed client has three pre-determined connection points

17 A sync agent on each Front Ends makes lazy writes to a blob store on SQL SQL Mirroring keeps two SQL instances (principle and secondary) up to date A 3 rd SQL instance, if configured as a witness, enables automated FO and FB Lync 2013 Pool Server instance as principal server for DB_1 Server instance as mirror server for DB_1 Witness server instance (optional) Data flow SQL transaction

FeatureHA Peer-to-peer (all modalities) Presence Conferencing (all modalities) UCWA Archiving CDR / QoE Federation PIC routing Unified Contact Store FeatureHA Topology Builder Lync Server Control Panel Persistent Chat Planning Tool PSTN Voice / E911* CAA / CAS / PVA / GVA RGS / CPS Call Admission Control XMPP

Two pools can be “paired” Backup agent on a Front End writes deltas to a DFS share DFS replicates share content between Lync pools Same as “pool failure”, but applied to geographically distinct pools

Pool 1Pool 2

The CMS contains configuration data about servers and services in your Lync 2013 deployment Each Lync deployment includes one CMS, which is hosted by the Back-End Server of one Front-End pool; if the pool hosting the CMS fails over, the CMS must be failed over as well During a pool failover that involves the pools hosting the CMS, the administrator must fail over the CMS before failing over the Front-End pool It is not necessary to fail back the CMS