Mg 1000T Switch Over To Survival Mode - Nortel 1000E Installation And Configuration Manual

Page 462 of 488

MG 1000T switch over to Survival Mode

Automatic Switchover to Survival Mode
553-3041-210 Standard 4.00
Configuring MG 1000T survivability and alternate primary controller
• Procedure 120: "Configuring the IP telephony node for Alternate
primary controller" on
• Procedure 121: "Verifying the operation of a Voice Gateway Media Card
in an MG 1000T expansion in Survivable Mode" on
• Procedure 122: "Retrieving CDR files using XModem" on
If survivability is configured on an MG 1000T, the following scenarios can
trigger a switchover to Survival Mode:
• Automatic Switchover — triggered when the MG 1000T Expansion
loses communication with the primary controller and the Switchover
Time Out (SWOTO) timer expires. This can occur if there is a
catastrophic failure of the primary controller, or the IP link is lost
between the MG 1000T Core and the MG 1000T Expansion.
• Manual Switchover — triggered with the Switchover to Survival (SOTS)
command in LD 135.
When an MG 1000T, with survivability configured, loses communication
with the primary controller, the MG 1000T automatically switches over to
Survival Mode when the SWOTO timer expires.
If the IP link is detected as down again before the expiration of the SWOTO
timer, the timer stops, and the MG 1000T remains in Survival operating
mode.
The state of communication between the primary controller and the
MG 1000T Expansion is monitored by a simple polling mechanism called a
Heartbeat.
This example illustrates the tasks performed by an MG 1000T Expansion
when communication with the MG 1000T Core is lost.
1 The MG 1000T Expansion attempts to re-establish the connection to the
MG 1000T Core. After four re-connection attempts with a pre-defined
delay between each attempt, the SWOTO starts.
September 2007
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