▁caused ▁by ▁bit ▁errors ▁or ▁packet ▁dro pping ▁in ▁con g ested ▁switch es ▁and ▁rou ters , ▁is ▁included ▁in ▁the ▁dat al ink ▁layer ▁or ▁network ▁layer ▁through put ▁but ▁not ▁in ▁the ▁good put . ▁ ▁Example ▁Im agine ▁that ▁a ▁file ▁is ▁being ▁transferred ▁using ▁HTTP ▁over ▁a ▁switched ▁E ther net ▁connection ▁with ▁a ▁total ▁channel ▁capacity ▁of ▁ 1 0 0 ▁meg ab its ▁per ▁second . ▁The ▁file ▁cannot ▁be ▁transferred ▁over ▁E ther net ▁as ▁a ▁single ▁continuous ▁stream ; ▁instead , ▁it ▁must ▁be ▁broken ▁down ▁into ▁individual ▁ch unks . ▁These ▁ch unks ▁must ▁be ▁no ▁larger ▁than ▁the ▁maximum ▁transmission ▁unit ▁of ▁IP ▁over ▁E ther net , ▁which ▁is ▁ 1 5 0 0 ▁bytes . ▁Each ▁packet ▁requires ▁ 2 0 ▁bytes ▁of ▁IP v 4 ▁header ▁information ▁and ▁ 2 0 ▁bytes ▁of ▁TCP ▁header ▁information , ▁so ▁only ▁ 1 4 6 0 ▁bytes ▁are ▁available ▁per ▁packet ▁for ▁the ▁file ▁transfer ▁data ▁itself ▁( Linux ▁and ▁Mac ▁OS ▁X ▁are ▁further ▁limited ▁to ▁ 1 4 4 8 ▁bytes ▁as ▁they ▁also ▁carry ▁a ▁ 1 2 - byte ▁time ▁stamp ). ▁Furthermore , ▁the ▁data ▁is ▁transm itted ▁over ▁E ther net ▁in ▁a ▁frame , ▁which ▁impos es ▁a ▁ 2 6 ▁byte ▁overhead ▁per ▁packet . ▁Given ▁these ▁overhead s , ▁the ▁maximum ▁good put ▁is ▁ 1 4 6 0 / 1 5 2 6 ▁× ▁ 1 0 0 ▁M bit /