2.8.3. Service Information 
IP station switchover can be likened to a reconfiguration. This means
that reconfiguration does not take effect after a system reload unless
the static data was written to the hard disk with EXEC-UPDAT:BP,ALL;
IMPORTANT:
If a system reload is performed after the IP stations
have been switched over to a board and before backing up the database
to the hard disk with the AMO UPDAT, the IP stations remain configured
on their old board after the reload. If this old board is still defective
or has been removed, switchover is not performed because the condition
that the board must be in operation at the time of the defect is not
satisfied (exception: a defective LAN cable cannot be detected until
the board is in operation, and in this case a switchover is performed).
The type branch to SMODE was introduced in the AMO CGWB for
this feature. SMODE describes the common gateway board’s mode.
SMODE mode determines whether a board is configured as a normal
board with IP stations, IP address, etc., or whether it is a Standby
board.
There are two versions of board’s mode:
STBYRDY: Means “ Ready” and describes a board that is
ready to inherit stations. Normally, the DC status of this board is “Ready”
because the board evaluates the mode and sends a positive load acknowledgment
to the system in response to STBYRDY”. The LAN status can be “Ready”
or “DEF”. If a board is to serve as a board, both its DC status
and the LAN status must be “Ready”.
STBYDEF: Means “ Defect” and describes a board from which
the IP stations were switched on account of a defect. This board cannot
serve as a board because its DC target status is “DEF”. Normally,
the DC status of this board is “DEF” or “NL” if the board is
inserted or “NPR” if the board is removed. The loadware that evaluates
the mode sends a negative acknowledgment to the system in response to
STBYDEF (DEF ON REQUEST).
Boards that are in mode do not have a separate IP address or any
board data. The board only receives all the board data (including the
IP address) when they are transferred to it from the source (defective)
board on switching over the IP terminals. Following switchover, the source
board is transformed into a board (for example, STBYDEF), which means
it no longer has an IP address. Although the board is physically connected
to the LAN, meaning that Layer 1 remains in operation, the higher layers
are deactivated. LAN-based access, for example over FTP, Telnet or SNMP,
is therefore impossible with a board.
IMPORTANT:
Please note that the Ethernet bit rate configured
in the board data is also transferred from the source board to the board.
The LAN segment to which the board is connected must therefore have
the same bit rate as the source board’s LAN segment.
The feature is restricted to a single system: cross-system application
is not supported.
It is possible, however, to organize the IPDA architecture in such
a way that the common gateway boards and boards are randomly distributed
over the OpenScape 4000 host system or in the AP (Access Point). In this
case, all boards must be connected to the LAN.
IMPORTANT:
It is important to note that LAN-based availability
is guaranteed so that not only the active board but also the board can
reach the IP stations and vice versa. In addition, be sure to trigger
the change in mapping of IP address to MAC address with the previously
mentioned ARP requests in the LAN components. This “gratuitous ARP“
request may not be blocked (e.g. in the router configuration).
We recommend testing the automatic switchover mechanism in the course
of initial start to ensure it is in working condition and ready to tackle
real defects.
As board data is also transferred in the course of manual and automatic
station switchover, restrictions apply if the switchover takes place
between fully configured (for example, Q2316-X10) and partially configured
boards (for example, Q2316-X). Please note the following in this case:
- No restrictions apply if the pool only contains boards of the same type, that is, boards that have the same DSP resources and thus the same number of active connections.
- If you are switching from a partially configured board to a fully configured board, then, following switchover, the number of active connections is restricted to the number supported by the partially configured system. You must increase the UDP port range to be able to use all of the fully configured board’s resources. Please note that any existing firewalls must be adapted in line with the new UDP range.
- If you are switching from a fully configured board to a partially configured board, then, following switchover, only a reduced number of active connections is possible on the new board, that is, the number supported by the partially configured board. This can lead to frequent blockages in configurations with many stations and high switching loads.
If manually switching the IP stations from a source board to a target
board (command: RESTART-BSSU:...,CGWSW=SWITCH,...;), then please note
the following points:
- The target board must be in STBYRDY mode and its DC status must be “Ready“ (for example, not locked by means of an AMO), and its LAN cable must be connected.
- The source board must not be in mode, that is, SMODE=NORMAL must be set. Otherwise, the board can display any DC status - it can even be locked by means of an AMO. If this is the case, the manual lock is transferred to the target board. If the DC status or the status of the source board’s LAN connection is “DEF” prior to switchover, SMODE=STBYDEF is entered after switchover. In all other cases, SMODE=STBYRDY is set, meaning that this board can once again operate as a board.
IMPORTANT:
To the extent that it plays a role in the switchover,
the LAN connection status (Layer 1) can be queried with the AMO BPOOL.
And of course you can use the AMO SDSU as before.
IMPORTANT:
To perform a SW update via GW Manager also the
STMIX/STMIY StandBy board needs a management IP address (CGWB) and a running
interface.
For Software Management functions like LW and OS Update from Assistant it is important
to
configure the STMIX/STMIY with a management IP address (CGWB) as described under Chapter ,
“Separate LAN Connectivity for Administration and VoIP”.