HP 3000 Manuals HP 3000 Manuals
Planning Routes in a Network
This section details how to plan routes. Information on how to configure
routes is in Chapter 10 . The screens used to configure routes are
detailed in Chapter 12 .
Each Administrator must define a route to each configured mailnode. A
route is defined in terms of the neighboring computer to which a message
addressed to a particular mailnode would be sent. The neighboring
computer is not necessarily the one on which the message's intended
recipient resides, it is just the next computer in the chain which leads
to the final destination.
Every computer in the network must have a route configured for every
remote mailnode in the network that it communicates with. This means
that every HP Desk Administrator must configure and, when sizing the
databases, count at least one route for:
* Each remote hierarchically addressable location for which the
local computer is not an NRC.
* Each remote mailnode on a hierarchically addressable location
which the local computer is an NRC.
* Each mailnode on remote locations which are not hierarchically
addressable.
When specifying the routes within a network, the main considerations are:
* To minimize data communication costs.
* To ensure that messages are delivered as quickly as possible.
NOTE The Administrator only needs to enter explicit routes when default
routing is not being used. See Default Routes for more
information.
Data Communication charges vary from one country to another.
To minimize data communication costs over the network the Network
Co-ordinator needs to:
* Investigate the data communication costs for the countries in the
network.
* Ensure that the highest volume of traffic is transported over
cheap links.
* Minimize the volume of traffic transported over the most expensive
links.
* Local Administrators configure their machines, so that mail
transmission is only possible when the cost of the data
communication links are low.
* Ensure data communication availability when links are set at
medium or cheap rates.
* Ensure that Urgent messages are urgent.
NOTE If you have HP DeskManagerPLUS, you can use NS data compression to
further reduce your data transmission costs.
HP Desk also allows you to configure when Normal and Deferred mail should
be sent during the day. To separate Urgent and non-Urgent mail, you
configure routes to each relevant mailnode through two or more computers
or gateways. Then configure a cheap route which allows only Normal or
Deferred mail to pass, and configure another (perhaps an X.25 line) which
allows only Urgent mail. This prevents large non-Urgent items being sent
over an expensive data communication line. Remember that the receiving
computer must be available when each of the lines are open, otherwise
messages can not be sent.
In our example, the Pharaoh Company's Network Co-ordinator has analyzed
the current situation and decided that the existing links between New
York and London, San Francisco and Chicago are economical and efficient
and should carry the bulk of the network traffic. The Corporate
Headquarter's HP 3000 will be the central machine in the network: the
bulk of all US and intercontinental traffic will pass through this
machine. This decision is sensible because most traffic will be sent
from and received by Corporate Headquarters.
This is a network of HP Desk installations and data communication lines
which will make up the Pharaoh system:
Local Computer Addressed Locations Route
(Neighboring
Computer)
--------------------------------------------------------------------------------------
NEWYORK MANF1 CHICAGO
SALE1 SANFRAN
EUCORP, MANF2, SALE2 LONDON
CHICAGO All NEWYORK
SANFRAN MANF1, MANF2, SALE2, USCORP, NEWYORK
EUCORP
SALE1/02 SINGPORE
SALE1/03 MELBRNE
SINGPORE All, inc. SALE1/01 and SANFRAN
SALE1/03
MELBRNE All, inc. SALE1/01 and SANFRAN
SALE1/02
LONDON USCORP, MANF1, SALE1 NEWYORK
MANF2 LVRPOOL
SALE2 GENEVA
GENEVA All LONDON
LVRPOOL All LONDON
Default Routes
To configure routes to other computers, it is possible to configure
default routes to be used by any remote machine. How to configure
default routes is described in Chapter 10 . If a mailnode will not
use the default routes, the route it will use must be configured
explicitly. If you configure a default route you won't have mail
building up because there isn't a route configured to the mailnode it is
intended for. If you forget to configure a route to a mailnode, the
default route is used.
If you change the default route, then the routing of all messages which
previously went through that default route is also altered. This allows
you to quickly modify message routing if a particular computer ceases to
function or has been removed on a permanent or semi-permanent basis.
For example, the HP Desk Administrator at the LONDON computer, may either
configure:
* Routes for every location on the network.
* NEWYORK as the default route and explicitly configure routes to
LVRPOOL and GENEVA. Routes are configured explicitly to LVRPOOL
and GENEVA because they do not use the default routes.
Planning Alternative Routes
Configuring alternative routes within your network minimizes
inconvenience if a primary link fails.
To set up alternative routes for a remote address, you configure
explicitly all of the routes to that address, including the default
route. This is because the default route is ignored if another route to
a mailnode is explicitly configured.
In our example, the Network Co-ordinator for the Pharaoh Company has
decided that SANFRAN and LONDON will be configured with alternative
routes through CHICAGO. So, for that those alternative routes CHICAGO
will be the neighboring computer to SANFRAN and LONDON, rather than
NEWYORK. CHICAGO does not need to know that it has been selected as a
route computer by SANFRAN and LONDON. The remote computer opens a line
and HP Desk looks after the transport.
Use Alternative Routes to prioritize URGENT mail. It is possible to set
up multiple routes so that URGENT mail can take one route and normal mail
another one (see Chapter 10 ). The main benefit from setting the
routes in this way is to minimize costs of data transmission.