A method of performing a dual connectivity operation to add a small secondary evolved Node B, SeNB, by a request of a master eNB, MeNB, in a heterogeneous network environment, the method performed by the MeNB to update a user plane path according to a SeNB addition comprising: determining a movement of part of services provided to a user equipment, UE, to the SeNB; transmitting, to the SeNB, a SeNB addition request message associated with establishing a connection between the SeNB and the UE, wherein the SeNB addition request message is for handover of the part of services; receiving, from the SeNB, a SeNB addition acknowledgment message for the SeNB addition request message, wherein the SeNB addition acknowledgement message includes information related one or more E-RABs to be switched in a downlink list in order to continuously provide, through the SeNB, the part of services provided by another SeNB, to the UE; transmitting a small cell path information notify message related to the update of the user plane path to a mobility management entity, MME; receiving a small cell path information notify response message for the small cell path information notify message from the MME; and transmitting, to the SeNB, an E-RAB information notify message, the method being characterized in that the small cell path information notify message includes: one or more information elements, IEs, indicating E-RABs to be switched in the downlink list and each comprising an E-RAB ID, a transport layer address, a General Packet Radio Service Tunneling Protocol, GTP, - Tunelling Endpoint Identifier, TEID, a cell identifier, ID, of a cell of the another SeNB providing the part of services prior to service switch, a cell ID of a cell of the MeNB, and information for notifying the MME that a path switch request message is small cell switch information, if the path switch request message is used, and in that each of the small cell path information notify response message and the E-RAB information notify message includes: one or more IEs indicating E-RABs to be switched in an uplink list and each comprising an E-RAB ID, and one or more IEs indicating E-RABs to be released in case th at the EPC failed to perform user plane path switch for at least one E-RAB. determining a movement of part of services provided to a user equipment, UE, to the SeNB; transmitting, to the SeNB, a SeNB addition request message associated with establishing a connection between the SeNB and the UE, wherein the SeNB addition request message is for handover of the part of services; receiving, from the SeNB, a SeNB addition acknowledgment message for the SeNB addition request message, wherein the SeNB addition acknowledgement message includes information related one or more E-RABs to be switched in a downlink list in order to continuously provide, through the SeNB, the part of services provided by another SeNB, to the UE; transmitting a small cell path information notify message related to the update of the user plane path to a mobility management entity, MME; receiving a small cell path information notify response message for the small cell path information notify message from the MME; and transmitting, to the SeNB, an E-RAB information notify message, the method being characterized in that the small cell path information notify message includes: one or more information elements, IEs, indicating E-RABs to be switched in the downlink list and each comprising an E-RAB ID, a transport layer address, a General Packet Radio Service Tunneling Protocol, GTP, - Tunelling Endpoint Identifier, TEID, a cell identifier, ID, of a cell of the another SeNB providing the part of services prior to service switch, a cell ID of a cell of the MeNB, and information for notifying the MME that a path switch request message is small cell switch information, if the path switch request message is used, and in that each of the small cell path information notify response message and the E-RAB information notify message includes: one or more IEs indicating E-RABs to be switched in an uplink list and each comprising an E-RAB ID, and one or more IEs indicating E-RABs to be released in case th at the EPC failed to perform user plane path switch for at least one E-RAB. one or more information elements, IEs, indicating E-RABs to be switched in the downlink list and each comprising an E-RAB ID, a transport layer address, a General Packet Radio Service Tunneling Protocol, GTP, - Tunelling Endpoint Identifier, TEID, a cell identifier, ID, of a cell of the another SeNB providing the part of services prior to service switch, a cell ID of a cell of the MeNB, and information for notifying the MME that a path switch request message is small cell switch information, if the path switch request message is used, and in that each of the small cell path information notify response message and the E-RAB information notify message includes: one or more IEs indicating E-RABs to be switched in an uplink list and each comprising an E-RAB ID, and one or more IEs indicating E-RABs to be released in case th at the EPC failed to perform user plane path switch for at least one E-RAB.