▁( Ge o ▁R outer ) ▁calcul ates ▁its ▁service ▁area ▁( ge ographic ▁area ▁it ▁serves ) ▁as ▁the ▁union ▁of ▁the ▁ge ographic ▁areas ▁covered ▁by ▁the ▁networks ▁attached ▁to ▁it . ▁This ▁service ▁area ▁is ▁approxim ated ▁by ▁a ▁single ▁closed ▁polygon . ▁Ge o ▁Rou ters ▁exchange ▁service ▁area ▁pol yg ons ▁to ▁build ▁routing ▁tables . ▁The ▁rou ters ▁are ▁organized ▁in ▁a ▁hierarchy . ▁ ▁App lications ▁Geographic ▁address ing ▁and ▁routing ▁has ▁many ▁potential ▁applications ▁in ▁ge ographic ▁mess aging , ▁ge ographic ▁advert ising , ▁delivery ▁of ▁ge ograph ically ▁restricted ▁services , ▁and ▁presence ▁discovery ▁of ▁a ▁service ▁or ▁mobile ▁network ▁particip ant ▁in ▁a ▁limited ▁ge ographic ▁area ▁( see ▁N avas , ▁ ▁Im iel i ński , ▁' Ge o Cast ▁- ▁Geographic ▁Address ing ▁and ▁Rout ing ' .) ▁ ▁See ▁also ▁Any cast ▁Geographic ▁routing ▁Ab iding ▁Ge oc ast ▁/ ▁St ored ▁Ge oc ast ▁Rout ing ▁Un ic ast ▁ ▁References ▁ ▁External ▁links ▁ ▁R FC ▁ 2 0 0 9 ▁G PS - B ased ▁Address ing ▁and ▁Rout ing ▁ ▁A ▁Survey ▁of ▁Ge oc ast ▁Rout ing ▁Pro tocol s ▁ ▁E fficient ▁Point ▁to ▁Mult ip oint ▁Trans fers ▁Ac ross ▁Data cent ers ▁ ▁Category : Internet ▁architecture ▁Category : Internet ▁broadcast ing <0x0A> </s> ▁Beautiful ▁Sk in ▁were ▁an ▁American ▁post - p unk ▁band ▁ext ant ▁from ▁ 1 9 9 7 ▁until ▁their ▁ 2 0 0 1