# Message Flow Through an NP Net Network

This section describes how a voice message flows through the NP Net network. From the sender’s point of view, if Name Broadcast mailboxes are used, there is no difference between sending a message to a local mailbox and sending one to a remote mailbox. (Name Broadcast mailboxes provide name confirmation across the network.) When a user receives a message from a remote mailbox, he or she hears "Remote message from [name]" where [name] is the name of the remote mailbox owner.

The diagram below is an overview of a message traveling from one node to another (San Jose to Boston). In this example, the dialing plan is configured such that mailbox numbers beginning with 8 are network numbers and that node 2 is Boston. In the discussion of the various NP Net functions in the following sections, the inner workings of the network are discussed in more detail.

The following paragraphs explain some of the processing shown in the diagram in more detail.

1. The user addresses a message to a destination mailbox, records it, and presses X to send the message, just as if it were being sent to a mailbox on the same system.

2. The NuPoint Voice software compares the leading digit of the destination mailbox with the dialing plan, where it finds an N or a P, indicating that the destination is a network mailbox.

3. The NuPoint Voice software then checks the Network Classes of Service (NCOS) assigned to the sender's mailbox to see if the operation is permitted.

4. The leading digits of the mailbox number are compared with the prefixes stored in the Digits Translation Table, where the number of the destination node is found.

5. The NuPoint Voice software checks the Network Node Table to be sure that the destination node is listed, and that access is enabled.

6. The message is put into the message queue that is waiting to be sent to that node.

7. The NP Net software checks the queue every thirty seconds to see if one of the queue thresholds has been reached, at which point it checks the Network Node Table for the hardware type, which provides the call setup instruction.

8. The connection is made, and messages are sent to the destination (remote) node.

9. The remote node uses the "digits to absorb" value to convert the mailbox number in the message header to a valid local mailbox by deleting the specified number of leading digits.

10. The remote node checks the size of the message to be sure that it does not exceed the node's network message limit. The remote node also checks the message size against the available space in the user's mailbox.

11. The remote node compares the Group Class of Service (GCOS) of the sending and receiving mailboxes, if the sender's Network Class of Service contains a feature that dictates this check. If the Gross match, or if they have even one group in common, the message is sent to the appropriate mailbox.

12. The receiving node converts the message timestamp (the message creation time) to local time and announces the converted time when the recipient plays the message. A receipt, which says that the recipient has not played the message, is sent back to the sender. If the sender keeps the receipt, NP Net will issue a receipt update during the first communications session established between the nodes after the recipient has played the message. The receipt update announces the time that the message was played, converted to the sender's local time.

13. If the recipient decides to answer the message, or if there is a receipt, the node number and sender’s mailbox number attached to the original message identify the destination mailbox on the originating node for return messages. Answers and receipts are not processed through the Digits Translation Table.