▁W ire less ▁L AN s , ▁mobile ▁ad ▁h oc ▁networks , ▁wireless ▁sensor ▁networks , ▁veh icular ▁ad ▁h oc ▁networks , ▁cogn itive ▁radio ▁networks , ▁L TE ▁ ▁etc . ▁ ▁Sim ulations ▁Most ▁of ▁the ▁commercial ▁sim ul ators ▁are ▁GUI ▁driven , ▁while ▁some ▁network ▁sim ul ators ▁are ▁CLI ▁driven . ▁The ▁network ▁model ▁/ ▁configuration ▁describes ▁the ▁network ▁( nodes , ▁rou ters , ▁switch es , ▁links ) ▁and ▁the ▁events ▁( data ▁transm issions , ▁packet ▁error ▁etc .). ▁Output ▁results ▁would ▁include ▁network ▁level ▁metrics , ▁link ▁metrics , ▁device ▁metrics ▁etc . ▁Further , ▁dr ill ▁down ▁in ▁terms ▁of ▁simulations ▁trace ▁files ▁would ▁also ▁be ▁available . ▁Trace ▁files ▁log ▁every ▁packet , ▁every ▁event ▁that ▁occurred ▁in ▁the ▁simulation ▁and ▁are ▁used ▁for ▁analysis . ▁Most ▁network ▁sim ul ators ▁use ▁discrete ▁event ▁simulation , ▁in ▁which ▁a ▁list ▁of ▁pending ▁" events " ▁is ▁stored , ▁and ▁those ▁events ▁are ▁processed ▁in ▁order , ▁with ▁some ▁events ▁trigger ing ▁future ▁events — such ▁as ▁the ▁event ▁of ▁the ▁arrival ▁of ▁a ▁packet ▁at ▁one ▁node ▁trigger ing ▁the ▁event ▁of ▁the ▁arrival ▁of ▁that ▁packet ▁at ▁a ▁down stream ▁node . ▁ ▁Network ▁em ulation ▁Network ▁em ulation ▁allows ▁users ▁to ▁introduce ▁real ▁devices ▁and ▁applications ▁into ▁a ▁test ▁network ▁( sim ulated ) ▁that ▁al ters ▁packet ▁flow ▁in ▁such ▁a ▁way ▁as ▁to ▁m im ic ▁the ▁behavior ▁of ▁a ▁live ▁network . ▁Live ▁traffic ▁can