The type of encapsulation protocol configured on this port's network interface. If tmnxPortEncapType has a value of 'nullEncap', frames received will not carry any tags or labels and as a result only one service can be configured on this port. Sometimes this is referred to as raw Ethernet packets.

If tmnxPortEncapType has a value of 'qEncap', ingress frames carry 802.1q tags where each different tag can signify a different service. This is not a valid value if tmnxPortClass has a value of 'sonetPath'.

If tmnxPortEncapType has a value of 'bcpNullEncap', Bcp is used on the sonet path as the NCP control protocol. The BCP IEEE 802 Tagged Frame Configuration Option (type 8) is negotiated to 'enabled'. VLAN tagged frames are allowed into the sonet path. Only a single SAP can be associated with the sonet path. 'bcpNullEncap' is valid only if tmnxPortClass has a value of 'sonetPath'.

If tmnxPortEncapType has a value of 'bcpDot1qEncap', BCP is used as the NCP control protocol. The BCP IEEE 802 Tagged Frame Configuration Option (type 8) is negotiated to 'enabled'. VLAN tagged frames are allowed on the sonet path. This encapsulation type is required when multiple SAPs are defined on the sonet path where each one is service delimited by a provisioned Dot1q tag. When 'bcpDot1qEncap' is specified, BCP does not enter the 'open' state unless the far end peer also supports 'bcpDot1qEncap'. This allows a LCP negotiation to transmit configuration request and confirmation messages to enable this feature. 'bcpDot1qEncap' is a valid value only if tmnxPortClass has a value of 'sonetPath'.

If tmnxPortEncapType has a value of 'ipcpEncap', BCP will not be used on this sonet path. IPCP NCP is used instead. 'ipcpEncap' is a valid only if tmnxPortClass has a value of 'sonetPath'.

If tmnxPortEncapType has a value of 'frEncap', Frame Relay is the expected encapsulation.

If tmnxPortEncapType has a value of 'pppAutoEncap', IPCP is automatically enabled. This encap type is only valid on ports/paths in network mode.

If tmnxPortEncapType has a value of 'atmEncap', the encapsulation on the port is ATM. The 'atmEncap' is also used when mirroring ATM ports.

If tmnxPortEncapType has a value of 'wanMirrorEncap', the port is used for mirroring of frame-relay and POS ports. On such ports no link management protocol would run.

If tmnxPortEncapType has a value of 'ciscoHDLCEncap', the Cisco HDLC encapsulation is applied. This encap type is only valid if TmnxPortClass has a value of 'tdm' or 'sonet'.

If tmnxPortEncapType has a value of 'cemEncap', encapsulation of frames will be circuit emulation. This is used to support transparent transmission of frames. This encap type is only valid if TmnxPortClass has a value of 'tdm' or 'sonet' in access mode.

tmnxPortEncapType is set to 'unknown' for physical SONET/SDH and TDM ports.