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n-1-1-014.90.1
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014.90.1 South Africa
by F. Jacot Guillarmod" <ccfj@hippo.ru.ac.za>
There are several networks in South Africa. The most visible is Uninet-ZA, a
research and academic network that links participating Universities and
research organisations via low speed TCP/IP trunks. There is also a loose
confederation of dialup uucp sites, known collectively as Sanet, which links
together private individuals and commercial undertakings in order to exchange
Usenet news and electronic mail. Gateways between Uninet-ZA and Sanet exist,
but are 'unofficial' in that there is considerable uncertainty as to their
legality in terms of third party traffic regulations.
Other networks include Fidonet, which has a substantial presence (and to which
Uninet-ZA owes a considerable debt of gratitude for services rendered); there
is WorkNet, which links up non-Governmental Organisations (NGO's) in South and
Southern Africa; and finally, several of the larger commercial organisations
(such as the SA Wool Board) have extensive but isolated TCP/IP based WAN's.
Recently, Uninet-ZA established a dialup uucp connection to provide email to
the University of Zimbabwe in Harare, and is in the process of setting up a
similar link to the University of Namibia in Windhoek. There is potential for
converting these rather unsatisfying low tech solutions into dedicated TCP/IP
links in the future.
Networking in South Africa took a giant leap forward in late November, when a
dedicated TCP/IP link to the United States was commissioned at Rhodes
University in Grahamstown. This link connects Uninet-ZA to RainNet in
Portland, Oregon, and from there into Alternet, and finally into the NSFNET.
Before this dedicated link was installed, connection to the Internet was
indirect, via uucp dialup between two Unix systems acting as gateways between
Uninet-Za and the Internet. Traffic volumes on this link had been showing
continuous growth, and the cutover point, where it became cheaper to rent a
dedicated circuit than to continue with dialup, were reached many months ago.
The process of cutting over from dialup uucp to a dedicated TCP/IP link has not
been trouble free. The link itself is a 9600 baud analogue circuit, but use of
V32.bis modems increases throughput to an effective 14.4kb. The routers on
either end are normal PC XT's, running the public domain ka9q package. On a
physical level, the link is remarkably stable. The cutover was planned in
several stages so as to integrate the Domain Name universes as painlessly as
possible. The first phase was to change the transport from uucp to SMTP
between the original gateway machines, while leaving Uninet-ZA and it's dummy
root domain isolated. The switch over went smoothly.
What was totally unexpected was the traffic volume. Within six hours of the
link being in place, there was a mail storm, consisting of replies from mail
based archive servers. The feeding frenzy had begun. Within the blink of an
eye, there were tens of megabytes of electronic mail queued up, and more
pouring in while users all over South Africa determinedly tried to import the
entire Simtel-20 archives as soon as possible. The fix was to increase the
number of machines acting as gateways on either side of the link, and to
artificially filter the 'worst' of the traffic until the situation stabilized.
In all of this, surprisingly, the bottleneck was on the gateway machines
themselves, and not on the bandwidth of the link.
The next phase of the integration was to ensure that RIP was propagating
effectively between Uninet-ZA and RainNet - a painless process. Slightly more
painful, in terms of paperwork, was providing detailed lists of IP network
numbers so that the router blocks into Alternet and NSFNET could be lifted.
The final phase of this exercise, which is in progress, is to merge the Domain
Name universes without committing the unpardonable sin of propagating bogons.
While intricate, this is proceeding smoothly, and by the time you read this,
there will be complete TCP/IP connectivity.
Of course, this won't be the end of the story. There never is with networking.
Computing Centre - Rhodes University - Grahamstown