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Table Of Contents

VMware, Inc. 25

ThisappendixintroducesInternetsocketsandprovidespointerstofurtherinformation.

 “A b o u t BerkeleySocketsandWinsock”onpage 25

 “ShortIntroductiontoSockets”onpage 26

About Berkeley Sockets and Winsock

Asocketisacommunicationsendpointwithanameandaddressinanetwork.Socketsweremadefamousby

theirimplementationinBerkeleyUNIX,andmadeuniversalbytheirincorporationintoWindows.

Mostsocket‐basedapplicationsemployaclient‐serverapproachtocommunications.Ratherthantryingto

starttwonetworkapplicationssimultaneously,oneappl

icationtriestomakeitselfalwaysavailable(theserver

ortheprovider)whileanotherrequestsservicesasneeded(theclientortheconsumer).

VMCIsocketsaredesignedtousetheclient‐serverapproachbut,unlikeTCPsockets,theydonotsupport

multipleendpointssimultaneouslyinitiatingconnec tionswithoneanother.

Datagoi

ngoverasocketcanbeinanyformat,andtravelineitherdirection.

ManypeopleareconfusedbyAF_INETasopposedtoPF_INET.Linuxdefinesthemasidentical.Thismanual

usesAFonly.AFmeansaddressfamily,whilePFmeansprotocolfamily.Asdesigned,asingleprotocolfamily

couldsupportm

ultipleaddressfamilies.Howeverasimplemented,noprotocolfamilyeversupportedmore

thanoneaddressfamily.ForInternetProtocolversion6(IPv6),AF_INET6issynonymouswithPF_INET6.

WinSockincludesvirtuallyalloftheBerkeleysocketsAPI,aswellasadditionalWSAfunctionstocopewith

cooperativemultitaskingandtheevent‐dr

ivenprogrammingmodelofWindows.

Programmersusestreamsocketsfortheirhighreliability,anddatagramsocketsforspeedandlowoverhead.

Trade Press Books

InternetworkingwithTCP/IP,Volume3:Client‐ServerProgrammingandApplications,Linux/PosixSocketsVersion,by

DouglasE.ComerandDavidL.Stevens,601pages,Prentice‐Hall,2000.

UNIXNetworkProgramming,Volume 1:TheSocketsNetworkingAPI,ThirdEdition,byW.RichardStevens(RIP),

BillFenner,andAndrewM.Rudoff,1024pages,A

ddison‐Wesley,2003.

Berkeley Sockets

WikipediaoffersanexcellentoverviewofthehistoryanddesignofBerkeleysockets.

ForreferenceinformationaboutBerkeleysockets,locateaLinuxsystemwithmanualpagesinstalled,andtype

mansocket.Youshouldbeabletofindbothsocket(2)andsocket(7)referencepages.

Appendix: Learning More About Sockets