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LAN E

LAN 4 LAN 3

12.10 P rocedures

The following subclauses define the protocol actions and procedures that are identified in the description of the State Machines contained in 12.8.

12.10.1 Discarding badly formed GARP PDUs

A GARP Participant that receives a GARP PDU shall discard that PDU if any of the following are true:

a) The PDU carries an unknown protocol identifier;

b) The PDU is not formatted according to the GARP PDU format defined in 12.11.

Items of information contained within a GARP PDU that are not understood by the GARP Application shall be discarded as described in 12.11.3.

12.10.2 Protocol parameters and timers 12.10.2.1 jointimer

The Join Period Timer, jointimer, controls the interval between transmitPDU! events that are applied to the Applicant State Machine. An instance of this timer is required on a per-Port, per-GARP Participant basis.

The maximum time period between transmitPDU! events is defined by JoinTime, as defined in Table 12-10.

12.10.2.2 leavetimer

The Leave Period Timer, leavetimer, controls the period of time that the Registrar State Machine will wait in the LV state before transiting to the MT state. An instance of the timer is required for each state machine that is in the LV state. The Leave Period Timer is set to the value LeaveTime when it is started or restarted;

LeaveTime is defined in Table 12-10.

12.10.2.3 leavealltimer

The Leave All Period Timer, leavealltimer, controls the frequency with which the Leave All state machine generates LeaveAll PDUs. The timer is required on a per-Port, per-GARP Participant basis. The Leave All Period Timer is set to a random value, T, in the range LeaveAllTime < T < 1.5*LeaveAllTime when it is started or restarted. LeaveAllTime is defined in Table 12-10.

12.10.3 Protocol event definitions

Unless stated otherwise in these event definitions, GARP PDU reception in a Bridge can occur through all Ports of a Bridge, and events generated as a result of such reception affect only those state machines that are associated with the Port through which the PDU was received.

12.10.3.1 ReqJoin

For an instance of the combined Applicant/Registrar state machine, the Applicant Only state machine, or the Simple Applicant state machine, the ReqJoin event is deemed to have occurred if the GID Service User issues a GID_Join.request service primitive for the Attribute instance associated with that state machine.

12.10.3.2 ReqLeave

For an instance of the combined Applicant/Registrar state machine, the Applicant Only state machine, or the Simple Applicant state machine, the ReqLeave event is deemed to have occurred if the GID Service User issues a GID_Leave.request service primitive for the Attribute instance associated with that state machine.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 12.10.3.3 rJoinIn

For an instance of the combined Applicant/Registrar state machine, the Applicant Only state machine, or the Simple Applicant state machine, the rJoinIn event is deemed to have occurred if a GARP PDU (12.11) is received, and the following conditions are true: