John said:
Hector Santos wrote:
How can you look at a portion of the network, a partial sketch of 3
servers amongst thousands, and declare this to be a star network? Maybe
you should have read instead of just looking at pictures:
"One notable difference between a BBS or web forum and Usenet is the
absence of a central server and dedicated administrator. Usenet is
distributed among a large, constantly changing conglomeration of servers
that store and forward messages to one another. These servers are
loosely connected in a variable mesh. This is similar to the complex
transportation plan of a city. There are multiple ways to get to any
point in the city. If one of those ways is blocked for some reason,
there is always another avenue available to get there. In this manner,
the User Network or Usenet allows newsgroup postings to reach their many
destinations robustly."
This is what a star network looks like:
http://en.wikipedia.org/wiki/Star_network
It is completely unsuitable for Usenet robustness, as mentioned in the
article:
"The primary disadvantage of a star topology is the high dependence of
the system on the functioning of the central hub. While the failure of
an individual link only results in the isolation of a single node, the
failure of the central hub renders the network inoperable, immediately
isolating all nodes. The performance and scalability of the network also
depend on the capabilities of the hub."
Whats funny about this is that you really don't know what it means
because you probably never operated or hosted a server.
I'll try to explain it to you:
Its relative - think of yourself as a HOST operator.
When you first install whatever hosting software you have, it begins
EMPTY!
Now YOU, as a HUMAN have to decide where you will get your feeds for
whatever information you wish to provide for your users and/or LOCALLY
HOSTED host operator.
Old school operators will understand terms like users as POINTS
HOST-JOHN <---> USER-A
The key point is that the USER is not hosting anyone else. But maybe
you are going to like to host other sites, free or fee or whatever:
HOST-JOHN <---> USER-A
|
HOST-BIZ-CUSTOMER
Relative to USER-A and the BIZ customer, YOUR are their HUB and its an
the form of a STAR.
In the old days, it was more of a locality, distance issue simply
because of the networking. But the internet allows you to go to other
HUBs now who offer the same feeds that you wanted.
There are MANY reasons, seriously, why users and nodes go to different
sources or multiple different sources.
Assuming you have access to anyone you are working with, its possible
to download form one host and upload to another. Its akin to reading
on this server and for some reason, you decide to post a reply via
google or some other site.
But keep in mind that USER and a HOST are different when it comes to
redundancy and duplicity.
If a HOST is going to go different multiple HOST for the same feeds,
the NNTP protocol has logic to check for dupes.
The point is today, you don't even think about it anymore. The
hardware, the bandwidth and software are that good to completely
automated it. It is still overhead, but its not something that was a
BIG BIG concern in the past where FEEDS are large and expensive. The
dupes where still there but if there was a real big issue, someone
traced it down to the problem node.
Lets put it this way, if you became an ISP - you will think STAR
network relative to yourself; you will sell services to NODES off your
hub - users and other hosting sites. You normally will not have any
control what this nodes will do themselves, but if one of your nodes
where getting duplicate feeds from someone else, and you UPLOADED it
to the hub, do you think they will accept it?