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real time and non-real time traffic

I confused when the result of two different simulation are not similar. i'm simulating real time traffic and non-real time traffic using UDP contant bit rate (CBR) and exponential respectively.The first simulation is done using the eurane extenstion to ns-2. In this extension, users are allow to create additional nodes (i.e. ue, bs and rnc) that are not defined in the original ns-2. The second simulation is done using the normal nodes defined in the orignal ns-2. For both simulation, I created 2 user equipments, 1 node b, 1 rnc, 1 sgsn, 1 ggsn, 2 nodes, 2 sinks Loss Monitor to measure the UDP bandwindth in Mbit per second. I created a bottle neck between sgsn and ggsn.

The result of the second simulation shows that the the real time traffic will suffer from mixing with non-real time traffics in the link congestion. The result of first simulation does not show any of that. I have set the same bandwidths between each duplex links for both simulation. Is it something do to with sink Loss Monitor or am I not tracing at the correct location?

I'm interested in measuring the throughput at the bottleneck link between sgsn and ggsn.

Anyone has come across any journals or literatures simulating real time traffic and non-real time traffic using UDP?

I got a reply:

The SGSN and GGSN in EURANE are just normal NS-2 nodes. If you placed
the bottleneck there then both simulations would be effected in a
similar way. However the effects of this bottleneck may be negated by
the high throughput possible with the HS-DSCH channel. Without knowing
the data rates of the traffic, and the channel model used for the
HS-DSCH, its difficult to say.

/Neill

Poisson simulation parameters

$Exponential1 set rate_ 384Kb
$Exponential1 set packetSize_ 210
$Exponential1 set burst_time_ 500ms
$Exponential1 set idle_time_ 500ms
$Exponential1 attach-agent $udp1

Is this correct? need to check..hehe

I found a website in order to emulate the poisson process set the burst_time_ to zero.

ns patch for gcc 4.0

Click here

I managed to do a simulation for best effort which consists of real time and non-real time data using UDP protocol. I'm trying to enhanced the script by finding the right simulation parameters.