Message delivering

NAME

: send_to, pass_message, send_both, port_send - Send messages from one node to another.

SYNTAX

:

      send_to( MESSAGE *m, int p )

      pass_message( int n )

      send_both( MESSAGE *m )

      int port_send( int n )

DESCRIPTION

:

• send_to sends message m on the port p. Additionally, it computes the delay of the tramsmittion and puts at the field m->port the port of the receiving node n from which this message will be received, increases by one the field m->hops and inserts message m in the receiving node's message queue PCB[n].mes_buf. send_to also schedules the corresponding event ( RECMES) for the recepient node. If the link relevant to port p is about to fail when message m is sent, then send_to doesn't insert the message in the receiving node's message queue nor does it schedule the corresponding event ( RECMES) for the receiving node. In case of the use of a synchronizer, send_to does not schedule the RECMES event. This event will be scheduled by the receiving node. For ring topology algorithms, port p can have the predefined values LEFTPORT, RIGHTPORT, which make send_to send the message to the left or right neighbour, respectively.

• pass_message does the same things as send_to does, by sending the currently received message CURMESS on port p.

• send_both can be used only in ring topology protocols; it sends message m to both neighbours of current node me. It has the same effects as send_to.

• port_send is an auxilliary function that returns the number port of current node me on which messages are sent to node n.

DIAGNOSTICS

The message sending routines produce error messages and cause the simulator to stop execution when an invalid node or invalid port number is given or a null message is tried to be sent.

SEE ALSO: System structure (Section 5.2), Simulator model (Section 4.1).