[ns] How to simulate mutiple priority queues in ns-2

[Thanh D. Do]

Hi folks,

I am a newbie with ns-2. I have a problem of simulating multiple
priority queues.

In Linux, normally, there is a socket buffer corresponding to each
connection. Data streaming into each socket buffer is encapsulated
into packets which obtain TCP headers and IP headers. Throughout this
processing, the packet streams corresponding to each connection is
kept separate. Finally, there is a single  “priority queue”, into
which all streams feed. All streams that have data ready to send take
equal turns draining into the priority queue. (FAIR)

There is another possible approach. Instead of a single priority queue
(transmit queue), there are 16 priority queues. These are called bands
and they range in number from 0 to 15, where band 15 has lowest
priority and band 0 has highest priority. All the connections of i
priority feed fairly into the i th priority queue. (SPRT).

I have attached a figure describing these two approaches.

My question is, is it possible to simulate both FAIR and SPRT in ns-2.
Could you guys give me some hints how to do that?

I really appreciate any suggestion.

Sincerely,
Thanh