"An SNMP context name or "context" in short, is a collection of management information accessible by an SNMP entity. An item of management information may exist in more than one context. An SNMP entity potentially has access to many contexts." In other words, if a management information has been defined under certain context by an SNMPv3 entity, then any management application can access that information by giving that context name.
A context is identified by the snmpEngineID value of the entity hosting the management information (also called a contextEngineID) and a context name that identifies the specific context (also called a contextName).Context Name and the Conextid need to be provided for an SNMPv3.