Standard Support is included with all Sitecore Maintenance Agreements and includes:
Standard Support offers a target response time that varies from one to three business days depending on the severity of the problem reported via the Sitecore Support Portal.
24x7 Premium Support is an optional upgrade that provides 24x7x365 telephone “hotline” support for business-critical issues. Designed to help customers maximize uptime, the response time for critical issues is reduced to one hour, 24 hours a day, 7 days a week. 24x7 Premium Support customers also enjoy enhanced response times for non-critical support issues.