Networking Survivability Features Summary Rev Nov., 2012

2 Case Study

3 Case Study 1 One of NS cabinet can be set up as Stand by CPU Master Backup Master Slave2 Slave3 1)While Master NS failed. NS assigned as “ Backup-Master” start to work like stand by CPU. 2)Slave 2 and 3 switch to connect with “Backup- Master” NS. 3)EXT under Master switch to connect with “Backup-Master” as “Secondary PBX”. 4) SIP Trunk can be backed up by “Backup- Master”. Slave1 ISP Item 1) and 2) : Please refer chapter “ 1.Backup-Master” Item 3) : Please refer chapter “3.Automatic Rerouting to Secondary PBX” Item 4) : Please refer slide #76-77 “ SIP GW fail over”

4 Case Study 2 NS work independently while Network has trouble Master Isolated Slave2Slave3 Slave1 While network down and each cabinet can’t see other then NS can work independently. IP/Legacy trunk and EXT terminated by each NS cabinet continue to work under each cabinet. Please refer chapter “ 2. Isolated mode”. Isolated

5 Over view

6 Individual Features 1.Backup-master Mode One of Slave unit become Backup-master and continue Onelook network service. 2.Isolated Mode Slave become independent system to serve CO and EXT connect own cabinet. 3.Automatic Rerouting to Secondary PBX NT or UT phone can divert to Secondary PBX and continue to work. There are below 3 key Features.

7 1.Back up Master

8 1-1 Over view

9 4 NS1000 are connected as One look. And Slave 1 is assigned as “Backup Master”. MasterBackup Master (Slave1) Slave2Slave3 Slave1 When Master died Slave1 become temporary master to run rest of system under One-look network.

Condition

Condition 1 4 NS1000 are connected as One-look network. And Slave 1 is assigned as “Backup Master”. MasterBackup Master (Slave1) Slave2Slave3 Slave1 Necessary Items; There is no additional hardware or Activation Key required to use “Backup Master” feature after establish “One-look Networking”. Because “Backup Master” feature is a part of “One-look Networking” feature. *All AK information transfer to “Back up Master” from “Master” and Temporary AK will be act based on information from Master. Temporary AK valid 10 days from when “Back up Master” start to act.

Condition 2 4 NS1000 are connected as One-look network. And Slave 1 is assigned as “Backup Master”. MasterBackup Master (Slave1) Slave2Slave3 Slave1 Necessary network arrangement; Full mesh VPN connection may need for all slave units able to connect with “Backup Master”.

Condition 3 4 NS1000 are connected as One-look network. And Slave 1 is assigned as “Backup Master”. MasterBackup Master (Slave1) Slave2Slave3 Slave1 Necessary Programming; 1)Set one of slave units as “Backup Master” from master unit. <= Only 1 “Backup Master” can be assigned 2)How long Keep Alive packet will be checked under One-look? -> “Multisite Keep alive Time-out time” 3)How long slave unit search for “Master” or “Backup Master” while start-up? -> ”Multisite startup monitoring time”

How to work?

How to work? 1 Master Backup Master (Slave1) Slave2Slave3 Slave1 Alive Check –Request from Master/Backup Master- Master SideAction Type of Alive message Unicast to each Slave unit Alive Message intervalInterval= Alive time out timer/4 Condition of detection as error No response from Slave with in timing of Alive message time out timer. Alive message time out timer Set at System Property “Multisite Keep alive Time-out time” Action while errorSend restart request to Slave and treat the Slave as FAULT. Keep Alive message from Master Keep Alive message from Backup Master

How to work? 2 MasterBackup Master (Slave1) Slave2Slave3 Slave1 Alive Check –Response from Slave- Slave Sideaction Type of MessageUnicast Message to Master Condition of detection as errorNot receive alive check message from Master for the timing of “Alive check timer”. Alive check timer“Multisite Keep alive Time-out time” value is down load from Master. Slave set timer little more than timer value that receive from Master. Action when got errorIf no Alive request from Master then Slave reboot itself. Randomize timing of responseTo avoid crowding response against Keep Alive from Slave to Master is randomize. Keep Alive response to Master Keep Alive response to Back Up Master

How to work? 3 MasterBackup Master (Slave1) Slave2Slave3 Slave1 No Keep Alive message from Master 1.Slave 1 not receive Alive Check Message from Master. 2.Slave 1 re-start to act as Backup Master. 1.Slave 2-3 not receive Alive Check Message from Master. 2.Slave 2-3 re-start and try to connect Backup Master? Alive Check – No Keep Alive message from Master

18 Change from “Master” to “Backup-master” 1-3 Sequence? 1 Backup-masterSlave Keep alive Master Keep alive ack. Keep alive timeout Restart as Backup-master Slave Restart Start req. Start ack. Keep Alive ack. Interval = Alive time out timer/4 Slave Restart

19 Start Ack. sequence 1-3 Sequence? 2 Repeat 3 times to send Start Req. In 30sec and Hold 60 sec as a 1 cycle Repeat this cycle until Multisite Startup time Time out (Default : 300sec) *Under Backup-Master scenario then send Start Ack. for both Master and Backup-master. Master/ Back up Master Slave Start Req. Start Ack. 10[SEC] Hold 60[SEC] Start Ack. 10[SEC]

How to work? 4 MasterBackup Master (Slave1) Slave2Slave3 Slave1 System Data Transfer –From Master to Backup Master- System Data from Master to Backup Master every time when data changed and saved or every 30 min. Synchronized data is follow - Setting data of Extension, Trunk, Group, System Speed Dial, Make/Receive Call setting Door phone ／ External Pager ／ External I/O, Time Service ・ Extension base setting such as Station Lock, War-Up, LCS, Auto Answer, Absent Message, Message Waiting, Incoming-Outgoing Log, FWD/DND ・ ICD-G base setting such as Message Waiting, FWD/DND, UCD monitor ・ Verification code, Pass word lock status ・ All AK

How to work? 5 -resource transition- MasterBackup Master (Slave1) Slave2Slave3 Slave1 Data on SRAM ・ SMDR ・ Error Log ・ EXT setting like Timed Reminder Remote Station Lock Check-In/Out Ready/Not Ready/Clean Up Login/Logout ・ EXT, CO, Verified Code base Charge Total Data on SRAM Not transfer to Backup Master Call Record can be collected and gathered by CA Call account.

22 UM 1-3 How to work? 6 -service transition- UM & IMAP4 Server is not backed up by “Backup Master”. If the customer request UM with “Backup Master” environment; 1) To use UM at each cabinet. 2) To use UM on Slave that is assigned as “Backup Master” for entire One-look network. Master Backup Master EXT-A Mail box for EXT-A

23 CA 1-3 How to work? 7-service transition- CA is not backed up by “Backup Master”. If the customer request CA with “Backup Master” environment; There is no instant solution to implement CA with “Backup Master”. 1)In case PBX mode CA client User need to change IP address of CA server (to Backup Master’s IP address) manually. 2) In case Server mode It is necessary to prepare separate CS server for Backup Master. And activate the CA server when Backup Master become active. And CA client User need to change IP address of CA server manually.

24 Other Resources/Services 1-3 How to work? 8 -resource/service transition- OGM is not backed up by “Backup Master”. OGM is necessary to record at independent NS cabinet. Play OGM record at Backup Master without OGM of Master WAV file transferring them to Backup Master. Time and Date Slave NS run own clock by “Manual / ISDN & Call ID(FSK) / SNTP” then “Time and Date” for Slave system continue to run by own clock under “Backup Master” environment. VoIP / Conference / Echo-Canceller / T-SW etc These resources will be released while One-look start to be controlled by Backup Master. Programming up date Automatic program up date will not be act. Manual Program Up date can be done.

25 How to recover from Backup mode 1-3 How to work? 9 - resume from Back Up Master to Master- 1)At home screen, select Master ICON and right click. 2)Select “Normal Mode” 3)Confirmation window come up “All site will re-start. OK?” 4)Master re-start and start to work as Master mode. 5)Slave re-start and re-connect to Master. “Normal Mode” has to be deployed manually to the Master unit to avoid sudden switch back from Backup-Master mode to interrupt service.

Programming

27 Select Back up Master mode at end of Unit addition wizard Define Backup Master at Wizard Mode 1-4 Programming 1 -Wizard-

28 Assign which Slave will be act as “Backup Master” Programming at Master unit 1-4 Programming 2 Note: When change Slave Unit to Back up Master, the assgined unit will be restarted

29 Programming at Master unit 1-4 Programming 3 1.“Multisite Keep alive Time-out time” value is used for Alive check for both Master and Slave. 2.”Multisite startup monitoring time” is used for Slave how long wait reply from Master whether start with Master/Backup Master or Isolated mode*. *Isolated mode describe at chapter “ Isolated mode”. 300

Error Notification

31 When Backup Master will become Active, there will be able to send below error message by Error Notification 【 Subject 】 KX-NS1000 System alarm#1 or KX-NS1000 System alarm#2 【 text 】 [System Name] :KX-NS1000 [MPR-ID] :AAAA-BBBB-CCCC-DDDD [Date] :11/12/31 [Time] :23:59:59 [Error Code] :535 [Sub Code] : [Error Message] :Change into Backup Master Mode Error message from NS address has to be set at each NS cabinet.

32 2 Isolated mode

Over view

Over view 1 Master Slave2Slave3 Slave1 4 NS1000 are connected as One-look network. If Slave can’t communicate neither Master or Backup master like when VPN network down all slave unit can’t talk to Master. Then each Slave become Isolated mode and run by itself but with some limitation. Isolated mode

Condition

Condition 1 4 NS1000 are connected as One-look network. Master Slave2Slave3 Slave1 Necessary Item Isolated mode Necessary Items; There is no additional hardware or Activation Key required to use “Isolated mode” feature after establish “One-look Networking”. Because “Isolated mode” feature is a part of “One-look Networking” feature.

Condition 2 Necessary network arrangement; “Spoke & Hub” or “Full mesh” whatever network arrangement is OK for “Isolated mode”. 4 NS1000 are connected as One-look network. Necessary Network Arrangement Master Slave2Slave3 Slave1 Isolated mode

Condition 3 4 NS1000 are connected as One-look. Necessary Programming; Enable “Isolated mode” to each Slave that is necessary to act as “Isolated mode”. Necessary Programming Master Slave2Slave3 Slave1 Isolated mode

How to work?

How to work? 1 Master Slave2Slave3 Slave1 Alive Check –Request from Master- Master SideAction Type of Alive messageUnicast to each Slave unit Alive Message intervalInterval= Alive time out timer/4 Condition of detection as error No response from Slave with in timing of Alive message time out timer. Alive message time out timer Set at System Property “Multisite Keep alive Time-out time” Action while errorSend restart request to Slave and treat the Slave as FAULT. Keep Alive message from Master

How to work? 2 Master Slave2Slave3 Slave1 Alive Check –Response from Slave- Slave Sideaction Type of MessageUnicast Message to Master Condition of detection as errorNot receive alive check message from Master for the timing of “Alive check timer”. Alive check timer“Multisite Keep alive Time-out time” value is down load from Master. Slave set timer little more than timer value that receive from Master. Action when got errorIf no Alive request from Master then Slave reboot itself. Randomize timing of responseTo avoid crowding response against Keep Alive from Slave to Master is randomize. Keep Alive response to Master

42 Change from “Slave” to “Isolated mode” 2-3 Sequence to be Isolated mode Backup-masterSlave Keep alive Master Keep alive ack. Keep alive timeout (Backup-master) Slave restart as Isolated Keep alive timeout (Master)

How to work? 3 Master Slave2Slave3 Slave1 System Data Transfer –From Master to Slave- System Data from Master to Slave System Data transfer from Master to Slave is done at every 30 min. Also transferring every time while data save at Master. Synchronized data is follow.Trunk, Group data Tennant/Trunk-G/Extension-G/UCD-G/Paging-G/Pick UP-G/Hunting-G/PS-G. System Speed Dial, Make/Receive Call setting Door phone ／ External Pager ／ External I/O, ・ Extension base setting such as Station Lock, War-Up, LCS, Auto Answer, Absent Message, Message Waiting, Incoming-Outgoing Log, FWD/DND ・ ICD-G base setting such as Message Waiting, FWD/DND, UCD monitor ・ Verification code, Pass word lock status and AK which related with Centralized ・ etc

How to work? 4 Alive Check –Response from Slave- 1.Slave not receive Alive Check Message from Master. 2.Slave re-start to act as Isolated mode. Master Slave2 Slave3 Slave1 No Keep Alive message from Master Isolated mode

How to work? 5 Resources Special Temporary AK(Centralized AK only) deploy to the Isolated NS from Master NS. Other resources is same condition as “Backup Master”

46 How to release Isolated mode to Slave? 2-3 How to work? 6 - resume from Isolated to Slave- Direct Log-In to the Isolated mode system. 1)At home screen, select Slave ICON and right click. 2)Select “Normal Mode” 3)Confirmation window come up “This site will re-start. OK?” 4)This Slave re-start and start to send Start Ack to Master or Backup Master.

Programming

48 Programming at Slave unit 2-4 Programming 1 Default: Disable.

Error Notification

50 【 Subject 】 KX-NS1000 System alarm#1 or KX-NS1000 System alarm#2 【 Message body 】 [System Name] :KX-NS1000 [MPR-ID] :AAAA-BBBB-CCCC-DDDD [Date] :11/12/31 [Time] :23:59:59 [Error Code] :537 [Sub Code] : [Error Message] :Change into ISOLATED Mode When Slave will become Isolated mode, there will be able to send below error message by . Error Notification Error message from NS address has to be set at each NS cabinet.

51 3 Recovery by IPPT -Primary/Secondary PBX-

Over view

Over view When the IPPT has no communication between NS where they Primary belong to then those IPPT can divert to connect secondary NS. IPPT mean UT/NT/UDT(SIP-DECT) except IPCS. If this primary-secondary feature is set for one EXT then two EXT port will be consumed. One at Primary NS and the other one at Secondary NS. Master (Secondary) Slave1 (Primary UNIT) The feature is slightly differ from that you knew same feature for TDE/NCP. The differences are described in following pages. The software version of UT1xx/248 should be V1.210 or later if use this feature.

Condition

Condition 1 Necessary Item Necessary Items; Activation Key may not required while Back Up Master used as “Secondary” If there is enough AK in Master to cover those EXT who move from Master. Thus temporary AK deploy for Back Up Master. Master (Primary) Back Up Master (Secondary) , Temporally AK

Condition 2 Necessary Item Necessary Items; Activation Key required to use* IPPT as “Secondary” PBX Extension telephone. If it is necessary to use “213” and “214” under Master PBX while Slave 1 can’t give service then 2 IPPT AK necessary to add for Master. *To assign IPPT to secondary PBX not require AK. Master(Secondary) Slave1(Primary) AK is required to support 213/214 on Master

Condition 3 Necessary network arrangement; VPN connection necessary to deploy communication in between Master and “213/214” extensions. Necessary Network Arrangement VPN Master(Secondary) Slave1(Primary)

Condition 4 Necessary Programming; NS: Assign “Secondary” port for the EXT needs Secondary PBX service. UT: “Primary” and “Secondary” PBX IP address is download from NS1000. NT/UDT: Necessary to assign Secondary PBX IP address at each NT/UDT. Necessary Programming Master(Secondary) Slave1 (Primary)

How to work?

How to work? 1- In case of NT - Alive check In case of NT 1) NS send Alive check packet to NT. 2) NT reply to NS. 3) NT not receive alive packet from Primary PBX then NT look for Secondary PBX with NT reboot. 4) Establish connection with Secondary PBX. 5) EXT 214 start to work with Master PBX. 6) Keep sending ARP to Primary PBX. Master (Secondary) Slave1 (Primary)

61 When IP-PT is in “Primary PBX”, it doesn’t send a “ARP” signal to “Secondary PBX”, because the priority of “Primary” is higher than “Secondary”. When LAN connection of “Primary PBX” is failed, IP-PT starts to send a “ARP” signal to “Secondary PBX”. Change from “Primary PBX” to “Secondary PBX” Secondary PBX IP-PT(NT) Primary PBX ARP (9 times) Keep Alive (every 5 sec) Answer for Keep Alive ARP LAN connection of “Primary PBX” is failed. Keep Alive (every 5 sec) Answer for Keep Alive ・・・・ IP-PT(NT) starts reboot ・・・・ IP-PT starts register to “Secondary PBX” ARP (every 60sec) *When IP-PT is in “Primary PBX” and “Primary PBX” stays alive, IP-PT does not switch to “Secondary PBX”. IP-PT does not switch to “Secondary PBX”. 3-3 How to work? 2 - In case of NT -

62 When IP-PT is in “Secondary PBX”, it sends a “ARP” signal to “Primary PBX” every 60sec. When LAN connection of “Primary PBX” is retrieved, IP-PT and PBX start the communication. “Secondary PBX” sends ”Keep Alive” to IP-PT every 5sec. “Secondary PBX” sends ”Keep Alive” to IP-PT every 5sec. “Primary PBX” sends “Keep Alive” to IP-PT every 60sec. “Primary PBX” sends “Keep Alive” to IP-PT every 60sec. After IP-PT switch back to “Primary PBX”, only “Primary PBX” sends “Keep Alive” to IP-PT. Change from “Secondary PBX” to “Primary PBX” Secondary PBX IP-PT(NT) Primary PBX ARP (every 60 sec) Keep Alive (every 5 sec) Answer for Keep Alive ARP Retrieve LAN connection of “Primary PBX” Keep Alive (every 60sec) Answer for Keep Alive ・・・・・・・・・・ IP-PT(NT) starts reboot Stop communication ・・・・ IP-PT(NT) starts register to “Primary PBX” Keep Alive (every 5sec) Answer for Keep Alive 3-3 How to work? 3- In case of NT -

63 Connect back to Primary PBX In case of NT 1)Detect ARP response from Primary while connect to Secondary. 2) IPPT connect back to Primary PBX with NT reboot. 3-3 How to work? 4- In case of NT Master(Secondary) Slave1(Primary)

How to work? 5- In case of UT - Alive check In case of UT 1) UT send PERIODIC Inform packet to NS. 2) NS reply to UT. 3) UT not receive reply packet from Primary PBX then UT look for Secondary PBX with UT reboot. [PERIODIC Inform] is keep alive of UT terminal. Master (Secondary) Slave1 (Primary)

65 When IP-PT is in “Primary PBX”, it doesn’t send a “ARP” signal to “Secondary PBX”, because the priority of “Primary” is higher than “Secondary”. When LAN connection of “Primary PBX” is failed, IP-PT starts to send a “ARP” signal to “Secondary PBX”. Change from “Primary PBX” to “Secondary PBX” Secondary PBX IP-PT(UT) Primary PBX LAN connection of “Primary PBX” is failed. Periodic (Inform Interval) IP-PT(UT) starts reboot ・・・・ *When IP-PT is in “Primary PBX” and “Primary PBX” stays alive, IP-PT does not switch to “Secondary PBX”. IP-PT does not switch to “Secondary PBX”. 3-3 How to work? 6- In case of UT - Periodic (Inform Interval) Periodic (10sec) Periodic (20sec) Periodic (40sec) Periodic (5sec) Resend times (5 times) Inform(BOOTSTRAP) IP-PT starts register to “Secondary PBX” ARP

66 Connect to Secondary PBX In case of UT 1)UT send PERIODIC inform to NS. 2)If there is no response against PERIODIC inform from Slave1/Primary. 3)Master send Reply (by PERIODIC inform) to UT with command that mention connect to Secondary NS. 4)UT start to connect with Master/Secondary. 3-3 How to work? 7- In case of UT Master (Secondary) Slave1 (Primary)

67 Connect back to Primary PBX In case of UT UT will back to connect primary NS while Master or Backup-master send “SetParameterValue” to UT while changing system back to “Normal” mode. 3-3 How to work? 8- In case of UT - UT can’t move back to primary NS system that is in Isolated mode Master (Secondary) Slave1 (Primary) 213

68 When IP-PT is in “Secondary PBX” and “Primary PBX” is back in work (Master or Backup-master get start ack from primary), then Master or Backup-master send “SetParameterValue” to UT. UT send ARP to Primary, Reg to Primary and restart to work with Primary. Change from “Secondary PBX” to “Primary PBX” Secondary PBX UT Primary PBX Inform (Periodic) ARP Retrieve Primary PBX ・・・・ Management Server change Stop communication IP-PT starts register to “Primary PBX” 3-3 How to work? 9- In case of UT - Master/B-MAS Retrieve Primary PBX Inform Res. (Periodic) Inform(BOOTSTRAP) SetParameterValues Device.ManagementServer.URL Inform Res. (BOOTSTRAP)

69 Connect to Secondary PBX How to work? 10- Mailbox - Mail box214 Mailbox has to be created at both PBX independently. These Mailbox has no integration. They work completely independent. Master (Secondary) Slave1 (Primary) When user need to use UM on Secondary NS, user need to create same Mail BOX to secondary Unit

Programming

71 Programming at NS - Virtual EXT card Programming 1 Create EXT is assigned as “Secondary” port as preparation.

72 Programming at NS - Virtual EXT card Programming 2 “Secondary Port Wizard” let you assign the EXT need Secondary connection to which NS1000. Primary NS location Choosing Secondary NS location Primary NS EXTs that doesn’t program with Secondary NS Primary NS EXTs that program with Secondary NS at this site.

73 Programming at NS - Virtual EXT card Programming 3 Clarify assign as Primary/Secondary PBX Information of Pair EXT. You can check at which EXT is paired with which EXT like below;

Error Notification

75 There is no Error message while IP telephone connect to Secondary NS. Error Notification Error message from NS

76 Other Back up features

77 SIP GW 1 SIP GW Fail over Master(Primary) Slave1 (Secondary) Back Up Master ISP In case of SIP GW on Slave assign as Backup-master and back up SIP GW, when Master become defective then Backup-Master start to send register requirement to ISP.

78 SIP GW 2 SIP GW Fail over If the SIP trunk that are used at Master need to be back up while Back up Master become active then it is necessary to assign as “Backup” at here. Assign as “Backup” means that this port will not send “REGISTOR” request to SIP provider unless unit become Back up Master.

79 UM Group 1 UM Group Fail over Master(Primary) Slave1 (Secondary) Back Up Master UM 500 UM 501 When Master NS running some of Trunk call is terminated by UM:500 on Master. If Master has failure and Back Up Master become active then those call automatically divert to UM:501 on Back up Master. Incoming call from Tunk/Ext

80 UM Group 2 UM Group Fail over UM Group Fail Over work against call like below; ・ Call through Trunk ・ Call through DISA ・ Call from EXT

81 Appendix

82 Master PBX Slave PBX Master PBX Slave ->Backup Master PBX Slave PBX Backup-master operation mode 1) Out of service on Master 2) Changing Slave to Backup Master 4’) Switching automatically over to Backup Master 3) Switching automatically over to Backup Master 4’) Re-connecting to PBX A B DescriptionFailover Time (Estimation)Remark A Time to detect lost of connection with Master and then switching to Backup Master. Detection of Time : 0’ 40” Switching Time : 3’ 30” Total : 4’10’’ All AKs on master unit are transferred to the backup master unit. Additional activation keys on Slave units are required if extra phones are deployed. Voice-path of P2P are maintained until the detection timer is expired. B Time to detect lost of connection with Master and then establish connection with Backup Master. Detection of Time : 0’ 40” Switching Time : 3’ 40” Total : 4’20’’ C Time to re-connect to another PBX (See “Redundancy of IP Terminal Registration”) CC C 2012.Feb.27

83 Master PBX Backup Master PBX Slave PBX Master PBX Backup Master - > Slave PBX Slave PBX Backup-master operation mode (Restoring) 1) Master PBX is recovered2) Changing Backup Master back to Slave 4’) Switching automatically Back to Master 3) Switching back to Master 4’) Re-connecting to PBX A B DescriptionFailover Time (Estimation)Remark A Time to recovering of connection with Master. Recovering Time : 2’ 40” Recovering of Backup Master to Slave is done by submitting the command via WEB-MC. Master notifies restoring itself by . B (Same as A) C Time to re-connect to PBX (See “Redundancy of IP Terminal Registration”) CC C 2012.Feb.27

84 Isolated operation mode 1) Isolated from Master 2) Switching to Isolated mode DescriptionFailover Time (Estimation)Remark A Time to detect lost of connection with Master and then switching to Isolated mode. Detection of Time : 0’ 40” Switching Time : 2’ 34” Recovering of working with Master (One-look networking) is done by submitting the command via WEB-MC. B Time to re-connect to PBX (See “Redundancy of IP Terminal Registration”) Master PBXSlave PBX Master PBX Slave -> Isolated mode PBX A or 3) Re-connecting to PBX B 2012.Feb.27

85 Primary PBXSecondary PBXPrimary PBXSecondary PBX 1) Running with Primary PBX 2) Losing connection with Primary PBX 3) Switching automatically over to Secondary PBX Primary PBXSecondary PBX Primary PBXSecondary PBX 6) Switching automatically back to Primary PBX Failover operation of IP Terminal 5) Primary PBX restored or 4) Running with Secondary PBX A B DescriptionFailover Time (Estimation)Remark A Time to detect lost of connection and establish connection with the secondary PBX. NT:1’ 00” / 1extn. (Detection Time : 20sec, Switching Time : 40sec) UT:4’19” / 1extn. (Detection of Time : sec, Switching Time : 4sec) No rebooting of Primary and Secondary PBX Additional activation keys on Secondary PBX are required to deploy extra phones. B Time to detect restore of Primary PBX and establish connection with it. (same as A) Total Failover Time (Target ） 3’ 00” / 640extn Feb.27

86 END

Networking Survivability_Rev1_28Aug2012Mar.ppt - 1 st release Networking Survivability_Rev1_1_6Sep2012Mar.ppt - Add comment to slide # Networking Survivability_Rev1_2_26Sep2012Mar.pptx - Change slide position to make better explanation flow. - Revise and add explanation to slide #40 - Add default value to slide #43 - Add slide # Networking Survivability_Rev1_3_25Oct2012Mar.pptx - Add slide # Networking Survivability_Rev1_4_31Oct2012Mar.pptx - Revise back ground picture on slide #21 - Add setting place to Slide #27 and #46 - Add remarks for Slide #49 - Add slide #67, swap slide order Modification

Networking Survivability_Rev1_5_6Nov2012Mar.pptx - Change “Combined Feature” to “Case study” and move to first part of this PPT Networking Survivability_Rev1_6_29Nov2012Mar.pptx - #53 Add following comment “The software version of UT1xx/248 should be V1.210 or later if use this feature.” - #64 Modify wrong sentence “PERIDIC” -> “PERIODIC” Modification