as <0x0A> </s> ▁In ▁tele communic ation , ▁a ▁" car rier ▁grade " ▁or ▁" car rier ▁class " ▁refers ▁to ▁a ▁system , ▁or ▁a ▁hardware ▁or ▁software ▁component ▁that ▁is ▁extremely ▁reliable , ▁well ▁tested ▁and ▁proven ▁in ▁its ▁capabilities . ▁ ▁Car rier ▁grade ▁systems ▁are ▁tested ▁and ▁engine ered ▁to ▁meet ▁or ▁exceed ▁" five ▁n ines " ▁high ▁avail ability ▁standards , ▁and ▁provide ▁very ▁fast ▁fault ▁recovery ▁through ▁redund ancy ▁( norm ally ▁less ▁than ▁ 5 0 ▁mill iseconds ). ▁ ▁Le if ▁Ek man , ▁professor ▁in ▁Tele communic ation , ▁states ▁that ▁" Car rier ▁grade " ▁is ▁not ▁a ▁standard ▁or ▁very ▁clearly ▁defined ▁term ▁but , ▁rather , ▁a ▁set ▁of ▁features ▁and ▁qual ities ▁that ▁make ▁the ▁product ▁acceptable ▁by ▁a ▁car rier : ▁The ▁feature ▁set ▁that ▁enables ▁the ▁car rier ▁to ▁util ize ▁the ▁business ▁with ▁use ▁of ▁that ▁equipment . ▁High ▁quality ▁and ▁very ▁good ▁M TB F ▁( Some ▁requirements ▁are ▁stated ▁in ▁TR - 1 4 4 ▁chapter ▁ 7 . 1 7 ). ▁Red und ancy ▁( if ▁one ▁part ▁goes ▁down , ▁there ▁is ▁an ▁alternative ). ▁E asy ▁and ▁cost - efficient ▁O & M . ▁All ▁Standard ized ▁as ▁much ▁as ▁possible ▁ ▁See ▁also ▁Car rier ▁Gra de ▁Linux ▁Real - time ▁computing ▁Red und ancy ▁( engine ering ) ▁Car rier ▁system ▁High ▁avail ability ▁ ▁External ▁links ▁What ' s ▁all ▁the ▁f uss ▁about ▁network ▁res il