HP 3000 Manuals HP 3000 Manuals
Networked Mail If HP Desk is installed on a number of computers in your organization, an HP Desk network can be established to allow communication within HP Desk from one computer to another. This communication is achieved with the use of NS or DS software to connect HP Desk systems. In an HP Desk network, the computer that your terminal or PC is connected to is the local computer and any others--whether they are part of the same installation or are located somewhere else--are remote computers. To users, the distribution of mail appears no different from a single computer system, because users do not need to know which remote computer their intended recipient uses. The routing of mail to other computers is organized by HP Desk, using information you supply when defining the system configuration. Routes Though a message contains a list of destination mail addresses, the message itself carries no information about how it will reach those final destinations - its route. Instead, the route of mail destined for a remote computer is defined in the configuration of the local computer. However, the local computer only knows the name of the next computer to which it must send the message--that is to say it holds no fully defined route map. At that next computer, the route is redefined to reference a neighboring computer, and so on, until the message reaches a computer where the mail address is recognized as a local one. Then it is passed to the Mailroom for delivery, in the normal way. This routing system is determined by the transmission method used by HP Desk. Mail Transmission HP Desk uses a store and forward technique to send mail around a network. This passes mail along a chain of linked computers, one step at a time. When a message arrives at any computer in the chain, a copy of the message is stored until that computer is ready to transmit the message forward. This means that all the links between the originating computer and the final destination computer do not have to be active simultaneously for the message to be transmitted - where necessary, the message is stored until the next link is active. When the message has been successfully transmitted to the next machine, the stored copy on the previous machine is deleted. It remains taking up space in the database until cleared out by HP Desk's Maintenance program, or if HP DeskManagerPLUS is installed, the Garbage Collector. A copy of the message is transmitted in this way to each addressee in the Distribution List who resides at a remote mailnode. So if a message is sent to users on ten remote mailnodes, ten copies of the message are transmitted. Hierarchic Addressing In a single-computer system, the form of addressing used is known as mailnode addressing. The number of separate transmissions of a single message required in an HP Desk network increases dramatically if mailnode addressing is the only type of addressing used in the network which effects performance and efficiency. HP Desk networks may be configured to use an alternative form of addressing to address this, known as hierarchic addressing. With hierarchic addressing, the sending computer only needs to know the name and location of the addressee - not their sublocation. So a message to Krista Carlson would be addressed to just Krista Carlson / USCORP.Thus hierarchic addressing relies on the recipient's full mail address residing in a remote computer's database. For any location configured as a hierarchic location, at least one computer must be configured to resolve the mailnode addresses for that location - that is, add the sublocations. A computer configured to support a location in this way is known as a node resolving computer (NRC). An NRC must hold in its Directory full details of all users on the supported location. The computer on which a location resides is usually configured as the NRC for that location. However, other computers may also, or instead, be configured as NRCs for that location. A message addressed to a remote, hierarchically addressable location progresses towards its destination by location code alone until it arrives at an NRC for the location. The NRC looks up the addressee's sublocation in its Directory and adds it to the Distribution List. Then it forwards the message to that sublocation. Intermediate computers create and forward only one copy of the message. Any location can be configured to be hierarchically addressable. Whilst a network can contain some hierarchic locations and some addressed by full mailnode, in most cases hierarchic addressing offers clear advantages. Example of Hierarchically Addressed systems If a message is sent to users on ten remote systems, two of those systems being Node Resolving Computers (NRCs) for four other systems, then only two messages are sent from the local computer to the two NRCs. At the NRCs the messages are sorted and addressed to each group of the four remote computers. A Network's Directory In a network, the Local Database holds route information. A typical computer's Global Database contains in its Directory: * Names of Local Users * Local Users' Mailnodes * Names of Remote Users * Mailnodes of Remote Users The address recorded for each remote user depends on the type of addressing used for the remote location--mailnode or hierarchic--and on the configuration of the local computer holding the database. If a location is addressed by mailnode, the Global Database of each computer in the network should hold a full mailnode address for every user recorded at the location. Similarly, any NRC for a hierarchically addressed location must hold the full address for every registered user on the location. Any remote computer that is not an NRC for a particular hierarchically addressed location, should record only the location code for each registered user at that location. If a user composes the Distribution List of a message, they need not type a mail address for any addressee whose name is held in the Global Database of your computer. If they specify a name that is not in the database, HP Desk lists users with similar names. When users enter only a location code for a location that is not hierarchically addressable, HP Desk tells them that a full address is necessary. When a user enters a full mail address for a hierarchically addressable location, the sublocation code is ignored until the message reaches an NRC for that location. The sublocation code is added at the NRC. If the name is not in the NRC's Global Database, it is forwarded to General Delivery. Mail Collectionand Delivery As mail collection and delivery is more complicated in a network of computers, the Supervisor has extra programs running under it. When the Mailroom sorts the mail from users' Out Trays and finds mail addressed to a remote location, it places the mail in the remote mail queue, for action by the Transport Manager. The Transport Manager controls the transport of mail to remote computers. To achieve this, it uses programs called trucks.