[ns] puzzles on Agent and Router

[Phenix]

Hi guys,

Recently I'm rather puzzled about Agent and Router in NS-2.
Take AODV for example, it is a kind of route protocol, meanwhile it's 
a kind of agent. Are agent and router equivalent?

And also, both agent and router have respective trace switch, 
-agentTrace and -routerTrace. Which one should I use when evaluating
my algorithm ?

Wish someone can give me some explains. Thanks in advance.

Regards,
Phenix