The encapsulation type is an access property of a service Ethernet port or SONET/SDH or TDM channel. The appropriate encapsulation type for the port or channel depends on the requirements to support multiple services on a single port or channel on the associated SAP and the capabilities of the downstream equipment connected to the port or channel. For example, a port can be tagged with IEEE 802.1Q (referred to as dot1q) encapsulation in which each individual tag can be identified with a service. A SAP is created on a specific port or channel by identifying the service with a specific encapsulation ID.