Survivable Media Gateways
Survivable Media Gateway (SMG) is a feature of Geographic Redundancy (from Release 5.0), whereby a Media Gateway
can register with an Alternate Call Server (AC1 or AC2) in the event of the Primary Call Server not being reachable.
This maintains (some) service in the event of an equipment or WAN outage. Ideally, an SMG will have some local trunking.
See also MGC Geo-Redundancy.
During normal operation, all MGC's are registered with the Primary Call Server.
Switching between Primary and Alternate Call Servers causes the MGC(s) to re-boot!
Call Pilot must be manually pointed to the Alternate Call Server Switch IP Address
- this is set in the Call Pilot Configuration Wizard: 'Meridian 1 Switch Information'
Call Server Configuration
- Package 404 (GRPRIM) is required on the Primary Call Server.
- Package 405 (GRSEC) is required on the Secondary Call Server(s).
The Primary Call Server customer database is automatically replicated to the Secondary Call Server(s), thus all the Call Servers are identical (see note). Per schedule, a compressed EDD backup is sent via SFTP (or FTP in Rel.5) to each SCS, where it is unzipped, restored, and sys-loaded. Database moves, adds, and changes should normally only be performed on the Primary Call Server.
Note: System-specific data, such as IP addresses, netmasks, routes, and nodes, is included in the replicated database but is filtered out and not restored on the Secondary Call Servers.
Database Replication Rule (BKPR)
Databases replication rules and schedules are defined in LD 117.
| NEW/ CHG BKPR xxx aaa ip yy | Add (or change) a backup rule, where:
|
| OUT BKPR xxx | Remove backup rule xxx |
| PRT BKPR xxx | Print backup rule xxx, or all if blank |
For example: NEW BKPR 1 SCS 192.168.89.5 2 SITE_02
Print configured Backup rules: prt bkpr
=> prt bkpr
Number of Backup Rules defined = 3
----------------------------------------------------
NN Dest Parameters N-of-vers Name
----------------------------------------------------
1 SCS 192.168.88.5 2 SITE_01 a Secondary Call Server
2 SCS 192.168.89.5 2 SITE_02 another Secondary CS
3 FTP 192.168.90.22 10 BACKUP FTP server for backups
mike
pbx/backups
=>
Database Replication Schedule (BKPS)
Databases replication rules and schedules are defined in LD 117.
| NEW/ CHG BKPS xxx yyy [<FREQ><DAY><HOUR><MINUTE>] | Add (or change) a backup schedule, where:
|
| OUT BKPS xxx | Remove backup schedule xxx |
| PRT BKPS xxx | Print backup schedule xxx, or all if blank |
Print configured Schedules: prt bkps
=>prt bkps Number of Backup Schedules defined = 3 ---------------------------------------------------- NN Backup-Rule Frequency Day Hour Minute ---------------------------------------------------- 1 1 Daily 1 0 site 1, daily at 1 am 2 2 Daily 2 0 site 2, daily at 2 am 3 3 Monthly 1 3 0 1st of a month at 3 am =>
Manual database replication
The database replication and restore procedures can be manually invoked (tested) in LD 43:
| BKR xx | Invoke database-replication operation, where: |
| RSR xx yy | Restore the database, where:
This command is typically entered on the Secondary system to restore a database received from the Primary system. Filtering of Primary system specific data (YES) must be used. |
System status
The status of each system in the Survivable Media Gateway configuration can be obtained in LD 135. On the Primary system, the system status identifies when the last successful database replication was completed, and whether the replication process is operating properly.
On the Secondary system, the system status identifies the Secondary system operating state, as well as the time and date of the last successful restore and sysload operations.
Obtain the system status for Primary or Secondary systems in LD 135:
| STAT GR | The current status of Survivable Media Gateway on the specified system appears. |
| STAT IPL xx | Status of the IP link for a specified MG, and indicates if it is registered to an Alternate CS, where:
Note: Use |
| SMGR xx yy | Forces Media Gateway to register on a specified Call Server,
where: An MG forced to switch to a Secondary Call Server remains registered to the Secondary Call Server until it is forced
to register back to the Primary Call Server with the |
• The Primary system status is obtained with STAT GR in LD 135:
- if a database replication attempt fails, a 'Failed Backup attempts' message is shown.
- when successful, the 'attempts' counter is cleared and the line no longer appears.
.stat gr Geographic Redundancy Status ---------------------------- Primary Call Server Automatic Replication Backup defined: SCHD Last Successful Replication Backup to 192.168.88.5 mode: Automatic Backup Rule number: 1 Secondary Call Server name: SITE_01 performed at: 01:07 on 03 13, 2014 Failed Backup attempts: 1, last one at: 02:14 on 03 13, 2014, to 192.168.89.5 ← ** Test activated: None Internet phones registered locally: 0 Media Gateways registered locally: 20
• Obtain the IP link status of each SMG with STAT IPL in LD 135:
.stat ipl IPMG 4 0: LINK UP IPMG 4 1: LINK UP IPMG 8 0: LINK UP IPMG 8 1: LINK DOWN IPMG 12 0: LINK UP
• Force a SMG to register back to the Primary Call Server with SMGR PRIM <cabinet number>.
- the following warning appears, if the response is
REGISTRATION SWITCH CAUSES SERVICE INTERRUPTION!
Please confirm YES/(Q)
• Use STAT IPMG in LD 117 for more info, such as IPMG registration status and uptime.