Κυριακή, Σεπτεμβρίου 16, 2007

Optimize your webpages

I think that Manuel Lemos does not need a lot of references. Every PHP developer has heard his name. A few days ago he wrote a very useful article for webpage optimization and since I have the time now I must mention it.

Κυριακή, Σεπτεμβρίου 02, 2007

Disappointed with ns-2

I am writing a survey for some common routing protocols, specifically the AODV, DSDV, DSR, TORA, GPSR, OLSR. For the simulations I chose ns-2 (latest version 2.31) mostly because it can be used in Linux although it is not installed from a deb/rpm file. I made some simulations and I wrote some shell and awk scripts for extracting data for statistics.

Although I have spent much time for scripting , I am not disappointed with this. My disappointment comes from the lack of help from the developers and expert users. I and everybody else who tried to make a simulation using TORA protocol had almost the same problem. But as it is seen in the ns-2 mailing lists when all these people sent an e-mail asking for help nobody answered. Even the sample scenarios for TORA do not work. The problem most people have is this:

...
"$ns node"
("for" body line 2)
invoked from within
"for {set i 0} {$i < $val(nn) } { incr i } { set node_($i) [$ns node] }" (file "10nodes_traffic50_stable.tcl" line 59)

....

I can say that maybe some settings are missing but the same happens with the samples!

The programming language of ns-2 is Tcl and C. Tcl is a little difficult, at least for me, language although I made some modifications to some Tcl programs. If I had more time I would learn Tcl but I don't. I tried to find some older versions of ns-2 like 2.26 but the latest I found is 2.29.

I hope that ns-3 will solve these problems. When I finish my work I will upload all my scripts because they are proven to be very useful.