1. Samsung Communication Manager Active-Active System Constraints Mar. 2013

2. Active-Active Redundant System 1 2 Mobile Transfer (CDMA) Data Center 4 3 SCM_1(Active) SCM_2(Standby) SCM_3(Active) SCM_4(Standby) HQ PSTN(HQ)PSTN(Branch) Branch Geographical redundancy The SCM systems can be working in different places to backup each other in case of emergency such as blackout, fire and earthquake. Enlarging scalability Maximum extension lines can be doubled.** ** i.g. In case of enterprise edition, max. capacity is 60,000 (30,000 + 30,000)

3. ① Required 4 SCM servers for Active-Active configuration (Active/Standby servers required for each node) ② SCM systems should connected on the same network domain even VPN technology could be used ③ The alive-check-timer will be expired, if there’s no response from each other for 10 seconds ④ Configuration for Nodes - All SCM servers should be same model, same SCM S/W version - Same international time zone should be set on each node. A slave node refer from master node time zone * Time display on user IP-Phone could be changed by user configuration Notice of Preparation Mobile Transfer (CDMA) Suwon Data Center(Slave Node) SCM_1(Active) SCM_2(Standby) SCM_3(Active) SCM_4(Standby) Seoul HQ (Master Node) PSTN(Seoul)PSTN(Pusan) Pusan Branch

4. ① There are master and slave node on a site - SCM administrator connected on master node could read and write but read only on slave node ② IP-Phones and GWs get profile from master node and conduct dual registration to both SCM ③ Master node conduct redundant DB saving process and call process will be done by it’s primary SCM ① If HQ SCM has damaged from emergency state such as black-out, fire and earthquake, Data Center SCM could keep service to HQ GW and phones ② Recovered from emergency in HQ, HQ GW and phones will register back to original HQ node ※ Same extension number is not allowed on a site Active-Active: Failover process Mobile Transfer (CDMA) SCM_1(Active) SCM_2(Standby) SCM_3(Active) SCM_4(Standby) PSTN(Seoul)PSTN(Pusan) Pusan Branch 1 4 2 3 Suwon Data Center(Slave Node) Seoul HQ (Master Node)

5. SCM_1(Active) SCM_2(Standby) SCM_3(Active) SCM_4(Standby) Case 1. A SIP Trunk line is connected to Master node - A unique company id on the master node is used to connect to ISP-SSW. If there’s an incoming call to an user which is registered to Suwon Data Center, the call would be passed via Seoul HQ node. - If there’s system crash on the Master node, SIP trunk calls could not be delivered. Case 2. Using SBC for call routing - The SBC should have some features to distribute a call by DID number. In case of system down on one of either, the other side could keep call processing ISP-SSW 070-700-1000~1999 070-700-2000~3000 SIP Trunk based on Active-Active 1 ISP-SSW SBC System Seoul HQ (Master Node)Suwon Data Center (Slave Node) 2

6. SCM_1(Active) SCM_2(Standby) SCM_3(Active) SCM_4(Standby) PSTN(Seoul)PSTN(Suwon) ① All gateways under Active-Active configuration should have registered to each Active node (Dual Reg.) ② If there’s system down on Seoul node, the PSTN gateway on Seoul would connect to Suwon SCM ③ If the Seoul PSTN gateway also down, All calls from/to PSTN will be routed via Suwon PSTN gateway ※ In case of incoming call, PSTN service provider should have automatic call re-routing feature. 1 2 PSTN Trunk based on Active-Active 3 Seoul HQ (Master Node)Suwon Data Center (Slave Node)

7. Descriptions for Functional Blocks Administrator Changing, Modifying would be done through the Active node On the Slave-node, just read-only permitted DB Exchange between Nodes DB Sync. will be started by the Slave node after connection established - While the Slave node is under DB sync. processing, all the call services will be done by the Active node Administration for changing DB is not permitted under link disconnection Service options for each extensions - It could be changed under the link disconnection state - The modified items will be synchronized automatically after the network link is re-established between the nodes System Management The notification alarm is monitored by each node Integrated Management - Billing: A billing machine should have link to all SCM node - Management Statistics : Each node save the own data for management statistics IP-Phone Failover IP-Phone will register to both SCM node(Dual Registration) - The dual registration information will be delivered from SCM (from IP-Phone profile) - If the primary SCM could not response in time, the IP-Phone will try to secondary SCM Changing the Active node will be notified to IP-Phones and gateways

8. Descriptions for Functional Blocks Gateway Survival Mode Dual Registration will be established by each gateway Both link disconnection cause the gateway running as survival mode SCM recovery information will be notified to gateway by primary SCM Embedded Application The embedded applications are running under each SCM Voice Mail/ Auto Attendant - Voice Mail, Call Recording, AME, Outlook service will be created only primary SCM § ”Out of Service” will be announced after the station is switch over to secondary SCM - The Quick memo feature is not working between the station under each Active nodes Conference Bridge - Meet-me Conference feature is not allowed on the secondary SCM § Conference Booking information is not shared between the SCM node - Ad-hoc, Progressive, Predefined, Conference On Answer, Barge-in features are available o n both SCM node ACD Lite and CSTA Service - The services are not allowed on the secondary SCM ** The IP-Phones and Gateways have dual registration information. The primary SCM is base system and the secondary SCM is backup system.

9. Descriptions for Functional Blocks External Application The Communicator and Messenger could be running on both SCM 3rd Party Application - The application should support Multi-SCM configuration. Etc. Constraints for Call Services - The Park and Retrieve feature is running under same node - The Callback feature is running under same node - The re-dial information is saved on each node - PMS interface doesn’t running under Active-Active configuration VQM - VQM is nor working under Active-Active configuration.