Re: [Blocks-development] Network simulator

[Blat F. <pet...@ho...>]

>With my new-found confidence in coding, I'd like to implement a network
>simulator.  (I'll probably do it in MFC, because that's what I use at 
>work.)

Cool. I still remember the gold old days when I used to
write code on my Amiga 500.

[Erik's design snipped]

>Erik has a good design, but I don't want to implement most of those 
>features
>yet.  I think that's overkill right now.
>
>I got the motivation to do the simulator a few days ago, after reading 
>about
>a similar test with Freenet:
>
>*digs for a link*
>http://freenet.sourceforge.net/index.php?page=icsi-revised
>
>Scroll about halfway down and look for Performance.

Nice graphs :-)

>I'd like to do those kinds of tests for Blocks.

Cool.

>
>First, I need to understand how Blocks works, in an informal
>protocol-inspecific way.
>(I had just fired up Visio and opened up some of the files in
>libblocks...and had brain-lock.  This is going to take some time.)
>
>At first, I'd like to look at the 'connection' mechanism, irrespective of
>routing blocks or bandwidth constraints.  I want to confirm that, for an
>arbitrary network size and *one* central connection point, can the network
>accommodate that number of hosts?  When hosts start to leave the network,
>will the network fragment?

Possibly. This is tied to the number of interconnections between
nodes.
>
>I'll start writing a simulator to answer these questions.  What rules 
>should
>the simulator use again?  It's been a while:
>
>1)  Messages route no farter than 6 hops

Yup, 6 hops max.

>2)  Hosts advertise themselves to other hosts.  (When?  How far are they
>routed?)

They are advertised by other servers when they receive a
connection, and by themselves once per hour if they have less
than 10 connections. This is to try and stop network
fragmentation.

>3)  When an existing host sees a new host on the network...somebody will
>choose to connect to someone else under some condition.  (When and under
>what conditions?)

If we see a server ad from advertising a server which is not
immediately adjacent we do the following calculation...

x=rand(255)-(16-n)*25

if x>0 we connect to the server

>4)  What a host has ten or more connections already and a new host connects
>to them, the existing host will give the new host a list of possible other
>connections and then ask the other host to disconnect.  (When will the new
>host disconnect, and when will he stay on anyway?)

Whenever any server recieves a connection it sends a list of
recent server ads to its new friend. The server ads are just
a small list (10) of previous servers. The new server ip/port
is added then added to the top of this list.

>
>That should get me started.  I'm going to go try to remember how to do a
>linked list.  :)

The fun stuff is the advert routing, but the connection stuff
is quite interesting as well. Graphs would be cool! :-)

ttfn

PG.

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