Discover the URL for your organization with IDiscoveryService web service
The IDiscoveryService Web service is used to determine the organizations that a user is a member of, and the endpoint address URL to access the IOrganizationService Web service for each of those organizations. This discovery service is necessary because Microsoft Dynamics CRM is a multi-tenant environment—a single Microsoft Dynamics CRM server can host multiple business organizations. By using the discovery Web service, your application can determine the endpoint address URL to access the target organization’s business data.For Microsoft Dynamics CRM 2015 and Microsoft Dynamics CRM Online 2015 Update installations, server and organization allocation may change as part of datacenter management and load balancing. Therefore, theIDiscoveryService Web service provides a way to discover which Microsoft Dynamics CRM server is serving your organization at a given time.The following table lists the Web service URLs for the worldwide Microsoft Dynamics CRM Online data centers.
Location
Identity
Provider
Discovery Web service URL
North America
Micr.
Account
https://dev.crm.dynamics.com/XRMServices/2011/Discovery.svc
Microsoft Office 365
https://disco.crm.dynamics.com/XRMServices/2011/Discovery.svc
EMEA
Micr.
Account
https://dev.crm4.dynamics.com/XRMServices/2011/Discovery.svc
Microsoft Office 365
https://disco.crm4.dynamics.com/XRMServices/2011/Discovery.svc
APAC
Micr.
Account
https://dev.crm5.dynamics.com/XRMServices/2011/Discovery.svc
Microsoft Office 365
https://disco.crm5.dynamics.com/XRMServices/2011/Discovery.svc
South America
Microsoft Office 365
https://disco.crm2.dynamics.com/XRMServices/2011/Discovery.svc
From: https://msdn.microsoft.com/en-in/library/gg328127.aspx