SOAP is the acronym for Simple Object Access Protocol. XML based messages over a NETWORK of computers are exchanged by using SOAP standard, using HTTP.
SOAP purpose:
A web service needs a combination of XML, HTTP and a protocol which is application-specific. A web service uses XML data for exchanging. The WEATHER service, stock quote service, look up service of postal DEPARTMENT are all sending XML messages and receiving an XML reply. This is the pattern that dominates the web services. To perform these web services, SOAP is the reliable protocol. 

SOAP is the acronym for Simple Object Access Protocol. XML based messages over a network of computers are exchanged by using SOAP standard, using HTTP.
SOAP purpose:
A web service needs a combination of XML, HTTP and a protocol which is application-specific. A web service uses XML data for exchanging. The weather service, stock quote service, look up service of postal department are all sending XML messages and receiving an XML reply. This is the pattern that dominates the web services. To perform these web services, SOAP is the reliable protocol.