Interchange

[cellspam]

Hi all,

Please can some one explain how the interchange works?
or and pdf or doc.

thanks

 

[jimbojimbo]

Interchange is no longer manufactured. Look at Avaya Message Networking.

 

[Midstream]

Are you asking about server interchange?

3.3 What is a Server Interchange ?
In the What is an Avaya Media Server section above, a number of server types were listed along with some
of their characteristics. One of these characteristics was duplication. Understanding the catastrophic nature
of an SPE failure, it is important to be able to provide SPE duplication to avoid a single point of failure. If
the servers are duplicated, then one server runs in an active mode and the one server runs in a standby
mode. The server in active mode is supporting the SPE which is currently controlling the Communcation
System. The server in standby mode?s SPE is backing up the active SPE. If there is a failure of the active
SPE, then the standby SPE takes over the system.
One feature of duplicated servers is the ability to shadow memory from the active SPE to the standby SPE.
One technique of achieving this is by having a dedicated memory board (DAJ or DAL board) in each
server and interconnecting them with a single-mode fiber. This method of memory shadowing is referred
to as hardware memory duplication. Another means for shadowing memory between a pair of servers is to
transmit the information over a high-speed, very reliable IP network. This method of memory shadowing
is referred to as software memory duplication and is not available for all types of media servers. For
performance reasons and bandwidth considerations, only a percentage of the system?s total memory is
duplicated between the servers. During steady-state operation, any changes made to the active server?s call
state memory are transmitted to the standby server. After these transmitted changes are applied to the
current state of the standby server?s memory, the standby server?s memory will be up-to-date with the
active server?s memory. The key, however, is that transmitted changes are applied to the current state of
9
the standby server?s memory and for that reason, if the current state was not up-to-date with the active
server before the changes were made, the transmitted changes have no context and therefore are useless. If
a standby server?s memory is up-to-date with the active server, the system is refreshed. If the standby
server?s memory is not up-to-date, the system is in a non-refreshed state. A standby server becomes nonrefreshed
if the communication between the servers has a fault or if either SPE goes through a restart. If
the system is non-refreshed, the active and standby servers go through a coordinated refreshing process to
get the standby server up-to-date and prepared to accept transmitted changes.
If the standby SPE is required to take over the system, it needs to transition to become the active SPE. The
process of a standby SPE becoming active is done through an SPE restart. As described earlier, there are
various types of restarts with each having different end user effects. The ideal restart level for an SPE
interchange is a hot restart, whereby the interchange would be completely non-service affecting. However,
this type of restart requires that the standby server have 100% of the memory state of the active server
before the failure. Unfortunately, the system does not achieve 100% memory duplication which implies
that a hot restart interchange is not supported between SPEs running on media servers. However, enough
memory is shadowed to allow a warm restart during the interchange process. This implies that a standby
SPE can take over for an active SPE through a system warm restart if the standby server?s memory is
current (or refreshed). However, if the standby server is not refreshed, the standby SPE can take over for
an active SPE, but only via a cold restart. In other words, if a standby server is refreshed, then it can take
over for an active server without affecting any stable calls in the system. If the standby server is not
refreshed, it can take over the system, but the interchange process will cause all calls in the system to be
dropped.

If so, go get this document:

Enterprise Survivable Servers (ESS):
Architectural Overview
written by
Greg Weber and Aaron Miller

 

[cellspam]

rockspop,

thanks for your help but i was looking info from the linux side.

thanks.