High Availability Exchange

Standby AMC-IP

The AlphaCom E20 and AlphaCom E26 exchanges can be equipped with a second AMC-IP card. Both AMC-IP cards are under control of the APC-card and report failure information to the APC, which for this purpose is equipped with a microcontroller. Based on that information the APC decides if and when to switchover between the 2 AMC-IP cards. This means that in the case of an AMC-IP card failure the down time of an E26 exchange is reduced to the time it takes for the standby AMC-IP card to take over rather than the time to get a new card from stock, program it and install it, which even if the card is an on-site spare, will easily take 30 minutes.

Hardware control

The supervisor of the system is a microprocessor plugged in on the APC card. <br\> The APC processor monitor the two AMC-IP cards by a dedicated I2C bus controlling some dedicated hardware I/O on the AMC-IP card. <br\> The two AMC-IP cards must be placed in board position 24 and 25.

Both AMC-IP cards can be configured with the exact same backup.bin database (also same IP adresses).

AMC status/events controlled by the APC (read by AMC):

#Standby/Master mode. In standby mode the MBI and Eth 1 are deactivated.
#Trig HW-reset of the AMC card.  

Status set by AMC read by the APC

1. Card is doing a HW-reset.
2. Standby request. When not set it means: "I am doing well and ready for doing my duty".
3. I WILL become a master. APC will reset current master. (Not used)

AMC master in "standby request" is running as long as the APC card is not taking any action.

License handling

For systems requiring licenses the following rules applies (Available from AMC 10.51):<br\>

• The AMC-IP in pos 25 must have a legal license
• The AMC-IP in pos 24 must have a free license

Switching of master

The active AMC board is only switched when a standby card status is reported OK and the master is setting the "Standby request" flag. <br\>

The standby request flag is set when:

• Hardware reset of the master card (Watch dog)
• Software reset of the master card
• Hot swap cable use on the master card
• If all connections to IP stations are lost after reaching the IP station registration trigger level.
• If the Stentofon Multidrop protocol fails. (This protocol can be active on both active and standby card)

Due to boot of Linux the switch between the AMC cards takes approx 1 min and 30 seconds.

Modules involved

RedBoot (boot loader) <br\> RedBoot repport correct "initial" system status to the I2C chip.

Linux <br\> Early in Linux startup the standby state is checked so that Eth 1 is not configured if the card is in standby. (Use Eth 0 for maintenance)

AlphaWeb<br\> Checks standby state and display "Standby" in red fonts if standby.

Watchdog software process<br\> Rapports amcd faults to I2C chip, because first "small" reset of AMCD is preformed in Linux and will not be notified by APC, (the second reset will be done by the hardware watchdog).

AMCD <br\> AMCD reports I am ready. There is an option for keeping a data link up in standby and relate the "I am ready" report to APC to the status of the data link. <br\>

Production of APC cards

File location:

svn://nooslzswiki/AMC_IP/apc/trunk/APC
Name of the file Apc.s09

The file is in Motorola (S-Record) hex-format. (Zero-fill programming <br\> buffer before load).

Production of Microcontrollers:

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Production can either be done from a master EPROM or directly <br\> from the data file. To produce a master EPROM, use a 27C64 <br\> type device, zero-fill programming buffer, load the hex file <br\> and program the device. Then use this EPROM to program the <br\> controllers. To program the controllers directly, use <br\> MC68HC705C8CFN 44-pin PLCC OTP controllers from Motorola or <br\> the equivalent devices from Harris, zero-fill programming <br\> buffer, load the hex file and program the devices. See the <br\> Manuals for the Programming Equipment for operating help. <br\> A 44-pin PLCC to 40-pin DIP adapter will probably be needed <br\> for direct programming of the controllers. <br\>

Production of AMC cards

AMC IP cards must have a FLASH image supporting correct I2C reporting from RedBoot <br\> (Q:\CSS_Development\Transfer\alphacom_images\alpha_image_hiav_20080626.zip) <br\> The AMC IP card must be of PCB version 8000/4 or newer. (Older version has no I2C chip)

Redundant power supplies

The AlphaCom E26 always has had support for redundant power supplies. This redundancy was supported by the old 1009701000 PSU, and is now supported by the 1009703000. Note that the power supplies operate in load sharing mode which increases the reliability even further, as each PSU is only loaded far below its capability, giving a much lower stress on the compents than for which they are designed.

Note that the redundant AMC-IP solution can also be use in an AlphaCom E20 exchange; this exchange however does not support redundant power supplies.

Ordering information

The components required for the AlphaCom High Availability exchange are available under the following numbers:

• 1009626010: High Availability exchange, dual AMC-IP with automatic switch over and 2 PSU's; additional AMC-IP filter card is included
• 1009626011: E26 High Availability extension package, AMC-IP card (including filtercard) and APC upgrade kit