HP 3000 Manuals HP 3000 Manuals
Hierarchical Addressing
In a single HP Desk system all users, locations, and so on are local. In
a network, users will want to send messages to users who are on other
computers. The screens used to configure hierarchically addressed
locations are detailed in Chapter 12 .
In a single HP Desk system the type of addressing used is called mailnode
addressing. To use this type of addressing in an HP Desk network can be
expensive. This is because the number of copies and transmissions of
messages may result in a heavy overhead for each computer in terms of
disk usage, computer time, and datacomm expense.
Hierarchical addressing is an effective and more economical alternative.
If the decision is taken to implement hierarchical addressing, the
Network Co-ordinator specifies which locations are to be addressed
hierarchically and which computers are to act as Node Resolving Computers
(NRCs) for them.
The NRCs must then maintain in their respective Global Databases, details
of all users and their mailnode addresses for each supported location.
Additionally each computer must configure those locations as
hierarchically addressable. Within a network most computers will be
configured as NRCs for all of their local locations; some may provide
local support for one or more remote locations.
The main advantage of using hierarchical addressing is that the addresses
for the greater proportion of messages are resolved as late as possible
along the route from originator to recipient. A hierarchically addressed
message must be copied by the source computer only for each locally
supported mailnode and for each remote location to which the message must
be forwarded. Compare this with a mailnode addressing system where the
source computer has to make a copy of the message for each local and
remote mailnode to which the message is addressed.
Where hierarchical addressing is adopted, users may send explicitly
addressed messages at any time.
For example, the message might have to go to a recipient who is currently
at a location at which he or she does not reside.
Users on an NRC cannot send mail hierarchically to locations for which
the addresses are resolved by their computer.
The Network Co-ordinator has decided that NEWYORK, LONDON, and SANFRAN
will be NRCs. They will support the following locations:
Node Resolving Location Supported
Computer
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NEWYORK USCORP
MANF1
LONDON EUCORP
MANF2
SALE2
SANFRAN SALE1