ΗΥ537: Έλεγχος Πόρων και Επίδοση σε Ευρυζωνικά Δίκτυα Βασίλειος Σύρης Τμήμα Επιστήμης Υπολογιστών Πανεπιστήμιο Κρήτης Εαρινό εξάμηνο 2008 Economcs
Contents The contet The basc model user utlty, rces and demand recoverng cost Margnal cost rcng Sharng fnte resources servce dfferentaton congeston rcng VBR and ABR Determnstc multleng 1998, C.Courcoubets, V.Srs, G.D.Stamouls Chargng ATM Servces OTE, Wnter 1998 Network Economcs - 3 The contet Communcaton servces are economc commodtes Suly factors: amounts of servces roduced technology of network elements wth management and control rules, network cost Demand factors: amounts of servces users want trade-offs between qualty of servce and wllngness to ay derved demand Market nteracton of network servce rovders and consumers trough rces comettve equlbrum: socal otmalty 1998, C.Courcoubets, V.Srs, G.D.Stamouls Chargng ATM Servces OTE, Wnter 1998 Network Economcs - 4
Termnology Termnology: rce: assocated wth unt of usage tarff: rce structure general form of rce, e.g., a+ (two art, nonlnear, tarff nstrument for ursung olcy obectves Nonlnear rces = nonlnear tarff charge: amount to be ad (bll tarff = chargng model 1998, C.Courcoubets, V.Srs, G.D.Stamouls Chargng ATM Servces OTE, Wnter 1998 Network Economcs - 5 Who sets rces? Three ossble answers Market: suly = demand Producer: mamze roft or deter otental comettors Prncle: nduce secfc acton. Prncle can be Provder Regulator Dfferent aroaches lead to dfferent rces Even cost can have multle defntons Hstorc cost (cost when devce was roduced Oortunty cost (value of roducng t Equvalent asset cost (cost of relacng t 1998, C.Courcoubets, V.Srs, G.D.Stamouls Chargng ATM Servces OTE, Wnter 1998 Network Economcs - 6
The customer s roblem Assume a market wth n customers and k servces Set of customers: N={1,,n} Customer can buy a vector quantty of servces =(1,,k for rce (, where Assume that the avalable resource are unlmted, and customer seeks to solve the roblem ( arg ma[ ( T = u ] ( s called demand functon 1998, C.Courcoubets, V.Srs, G.D.Stamouls = ( = =, K, T { } Chargng ATM Servces OTE, Wnter 1998 ( 1 k Network Economcs - 7 User utlty User utlty u(: level of satsfacton for quantty of servce Usual to assume that u( s strctly ncreasng and strctly concave But ths s not always the case Margnal utlty of servce u ( Decreasng functon of 1998, C.Courcoubets, V.Srs, G.D.Stamouls Chargng ATM Servces OTE, Wnter 1998 Network Economcs - 8
Takng nto account user utlty User utlty: Global lannng roblem: But, dffcult to know all utltes Under condtons (utlty s concave, the above can be solved dstrbuted usng rces and allowng each user to solve ma{ u ( } Prce set such that ( = C 1998, C.Courcoubets, V.Srs, G.D.Stamouls ma { } u ( Demand functon u ( ( s. t. Chargng ATM Servces OTE, Wnter 1998 C Network Economcs - 9 Takng nto account user utlty User utlty: Global lannng roblem: But, dffcult to know all utltes Under condtons (utlty s concave, the above can be solved dstrbuted usng rces and allowng each user to solve ma{ u ( } Prce set such that ( = C 1998, C.Courcoubets, V.Srs, G.D.Stamouls ma { } u ( Demand functon u ( ( s. t. Chargng ATM Servces OTE, Wnter 1998 C Network Economcs - 10
Proertes of aroach Network does not need to know utlty of all users Decentralzed soluton, each user acts to mamze ther own beneft Sharng done by users, not nternal network mechansms Network only rovdes rce (=congeston sgnal Incentve comatblty: best soluton for each user mamzes aggregate utlty (socal welfare Effcent (economc resource utlzaton: caacty s used n full, by those who value t most 1998, C.Courcoubets, V.Srs, G.D.Stamouls Chargng ATM Servces OTE, Wnter 1998 Network Economcs - 11 Net beneft mamzaton Customer s net beneft or consumer surlus: CS = ma[ u ( T ] utlty u( mamzed net beneft = ma [u( ] 1998, C.Courcoubets, V.Srs, G.D.Stamouls 0 ( Net beneft mamzed at u( = Chargng ATM Servces OTE, Wnter 1998 Network Economcs - 12
Demand curve and surlus Consumer surlus CS ( = ( 0 ( d ( $ CS( u ( = 1998, C.Courcoubets, V.Srs, G.D.Stamouls 0 Chargng ( ATM Servces OTE, Wnter 1998 Network Economcs - 13