Avaya S8700 Maintenance Manual page 1965

PKT-INT (Packet Interface)
On S8700 Multi-Connect, all down-stream packets go to the active PKT-INT, but
the up-stream packets can come from the active and the standby PKT-INTs during
the migration process.
Link migration is performed to prepare the standby PKT-INT for a hot reset.
RNRs are not sent to the endpoints at the start of the link migration.
PCD tells the active and standby PKT-INTs that a link migration is starting.
LAP-D links are migrated from the active-mig PKT-INT to the standby-mig
PKT-INT in the order they appear in the internal list. (Links without data do
not migrate first. The entire migration happens so quickly that delaying a
few hundredths of a second would seldom clear a link's preexisting data.)
Active-mig PKT-INT continues to accept up-stream messages for the links
that are not yet migrated. The standby-mig PKT-INT starts accepting
up-stream messages for the links that are migrated. Both the active-mig
and the standby-mig PKT-INTs send up-stream messages to the PCD.
PCD accepts up-stream messages from both the active-mig and
standby-mig PKT-INTs.
PCD sends every down-stream message to the active-mig PKT-INT and
has the active-mig PKT-INT forward it to the:
— active-mig PKT-INT of links that have not yet migrated
— standby-mig PKT-INT of links that have migrated
At the end of the migration, the active-mig PKT-INT tells the PCD that the
migration is finished, and PCD tells the standby-mig PKT-INT to go active
(hot interrupt). Some coordination verifies that every up- and down-stream
message has been flushed from the active-mig PKT-INT before completing
the interchange.
PKT-INT and System Reliability
A PKT-INT circuit resides on each IPSI board. LAPD links are terminated by the
PKT-INT circuits in the IPSIs that are distributed out to the port networks. The
non-IPSI-terminated port networks do not have their own PKT-INT capability so
their LAPD links are terminated by IPSIs in the IPSI-terminated port networks.
S8700 Multi-Connect architecture has three items that can be duplicated for
increased reliability: media server, IPSI, and PNC. They can be duplicated
independently. Note that duplicated control networks and duplicated IPSIs go
together. That is, when the IPSIs are duplicated, the control networks must be
duplicated. The set of items in your configuration that are duplicated depend on
the reliability option chosen for your system: duplex, high or critical. See
8-507.
555-233-143
Table
Issue 1 May 2002 8-1243