Checkpointing circuit states

ISUPStatusReq supports two event types for circuit state checkpointing. These event types are:

Event type

Description

CIRGRPSET

Circuit group set status.

CIRGRPGET

Circuit group get status


Both status request types use the range and status information element. For the purposes of the two new status request types, the range and status information element fields are used as follows:

Field

Description

range

Number of circuits to modify (minus one). For example, to modify 24 circuits, the range value is 23.

status

An array of length range + 1. Each byte of the array contains the circuit status for one circuit.


The circuit status is encoded and decoded as:

MS four bits    = circuit Blocking status
    BSNOTBLK    = Idle
    BSRMTBLK    = Remotely Blocked
    BSLOCBLK    = Locally Blocked
    BSLOCRMTBLK = Remotely and Locally Blocked

LS four bits = circuit Call status
    CSIDLE    = Idle
    CSINCBUSY = Incoming Busy
    CSOUTBUSY = Outgoing Busy

For example, if a circuit is locally blocked and the incoming circuit is busy, its status byte is encoded as 0x21. If it is not blocked and the outgoing circuit is busy, then its status byte is encoded as 0x02.