Functional Description - Avaya Nortel Communication Server 1000 Reference

NTBK22 MISP card

Functional description

Each MISP can support 4 line cards (UILC or SILC or any combination of the two). Each line
card supports 8 DSLs, therefore each MISP supports 32 DSLs. As each DSL uses two B-
channels and one D-channel the MISP supports 64 B-channels and 32 D-channels. If the MISP
is carrying packet data, it must dedicate one of its D-channels to communicate with the external
packet handler. In this case the MISP supports only 31 DSLs.
The main functions of the MISP are:
• communicate with the Call Server CPU to report ISDN BRI status and receive downloaded
application software and configuration parameters
• manage Layer 2 and Layer 3 signaling that controls call connection and terminal
identification
• control terminal initialization and addressing
• assign B-channels for switched voice and data transmission by communicating with the
BRI terminal over the D-channel and allocating to it an idle B-channel with appropriate
bearer capabilities
• separate D-channel data from signaling information and route the data to the packet
handler
• send call control messages to ISDN BRI terminals over the D-channel
Micro Processing Unit (MPU)
The MPU coordinates and controls data transfer and addressing of the peripheral devices and
communicates with the CPU using a message channel on the CPU bus. The tasks that the
MPU performs depend on the interrupts it receives. The interrupts are prioritized by the
importance of the tasks they control.
High-Level Data Link Controller (HDLC)
The HDLC is a format converter that supports up to 32 serial channels that communicate at
speeds up to 64 kbps. The HDLC converts messages into the following two message formats:
• a serially transmitted, zero-inserted, CRC protected message that has a starting and an
ending flag
• a data structure
548 Circuit Card Reference
Comments? infodev@avaya.com
July 2011