Software Times Return of MAD Response

When the SM or a GSM issues a request MAD that should cause a response MAD to be returned, the manager software entity rather than the SMI or GSI is responsible for starting a timer upon issuance of the request MAD. If a response is not received before the timer expires, the software-based management entity is responsible for retrying the request MAD transmission. How many retries are performed and what actions are taken when retries are exhausted is outside the scope of the specification.

The software management entity derives the timeout from the following:

• Each port on a CA or a router and the management port on a switch implements the following two attribute elements:

  - PortInfo.SubnetTimeout attribute element. This value is programmed by the SM and indicates the maximum time for a response from this port to reach any other port in the subnet. The maximum time is calculated as 4.096us X 2^{SubnetTimeout}

  - PortInfo.RespTimeValue attribute element. This hard-wired, read-only value indicates the amount of time from a port's receipt of a request MAD until the corresponding response is sent, or between the port's transmission of successive MADs that are part of a multi-MAD sequence (e.g., in response to the receipt of a SubnAdmGetBulk() request MAD). The time is calculated as 4.096us X 2^{RespTimeValue}.

• The maximum expected interval between the transmission of a request MAD and the receipt of the corresponding response MAD =(2 X (4.096us X 2^{SubnetTimeout})) + (4.096us X 2^{RespTimeValue})

• The maximum expected interval between the reception of the successive response MADs of a multi-MAD response sequence = (4.096us X 2^{SubnetTimeout}) + (4.096us X 2^{RespTimeValue})