MINI-LINK BAS 6-24
Technical Description EN/LZB 111 0542 P2B
In order to maintain consistency, the processes, which control the
logical units, retain no information about cross connections. If should
they need details about cross connection, they have to explicitly ask
the connection handler.
The connection handler also stores a list of dependencies for each
cross connection. It is a list of the circuit boards through which the
cross connection passes. This list is stored in order to allow re-
establishment of cross connections after hardware or software failures.
In case of hardware failure or ATM level alarm, the list is also used to
point out which cross connections are affected by the alarm itself.
6.7.2 Cross Connection Re establishment
Cross-connection re establishment is needed when the contact with
one or more boards has been re established after it was lost before.
This procedure consists of the following steps:
• Find out the boards for which the contact has been established
again.
• Retrieve, from the connection handler database, the list of cross
connections that are affected by these boards.
• Start an audit for all affected boards. This means assuring that the
correct cross connections are set-up and all others are removed.
In both cold and hot restart there may be connections, which cannot be
re-established. For example, the connections may use interfaces or
circuit boards which have been removed or which have failed. These
connections are retained in the connection handler database but are
marked as “not re established”, as shown in Figure 6-9. These
connections will thus not just disappear but will be visible through the
management system as having their operational state set to disabled.
6.7.3 Connection Supervision
The cross connection supervision is essentially based on the relation
between cross connections and the related resources. Fault
management on any resource used by a cross connection, typically
boards, interfaces and physical links, will result in alarms on such a
resource and in a consequent change in operational state of the
affected cross connections.
Therefore the cross connections supervision is essentially based on the
fault management procedures for the resources used by such a cross
connection.
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