Service routing for user equipment

1 . An apparatus comprising:

at least one processor; and

at least one memory, said at least one memory stored with computer program code thereon,

the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform:

receiving a service request from a user equipment;

selecting at least one control plane routing identifier for the user equipment, the control plane routing identifier corresponding to one of a plurality of control plane entities in a network;

sending the at least one control plane routing identifier to the user equipment;

receiving a message comprising a lower layer protocol header comprising the control plane routing identifier; and

routing the message to the one of the control plane entities based on the control plane routing identifier.

2 . The apparatus according to claim 1 , wherein the apparatus is further caused to perform:

activating at least one signalling radio bearer for the user equipment for carrying control plane messages; and

sending indication of the activated at least one signalling radio bearer to the user equipment.

3 . The apparatus according to claim 1 , wherein the apparatus is further caused to perform:

associating the at least one control plane routing identifier with one or more specific messages and/or triggering conditions.

4 . The apparatus according to claim 1 , wherein the apparatus is further caused to perform:

selecting a plurality of control plane routing identifiers for the user equipment and associating each of the selected control plane routing identifiers to a specific message and/or triggering condition.

5 . The apparatus according to claim 1 , comprising a protocol stack having two or more layers in hierarchical order, wherein the apparatus is further caused to perform:

including the control plane routing identifier in a message header of a layer below the highest layer in the hierarchical order of layers.

6 . The apparatus according to claim 1 , wherein the apparatus is further caused to perform:

including the control plane routing identifier in at least one of a packet data convergence protocol header, a radio link layer header, a medium access layer header.

7 . The apparatus according to claim 5 , wherein the apparatus is further caused to perform at least one of the following:

indicating the at least one control plane routing identifier explicitly in the message header;

indicating the at least one control plane routing identifier implicitly in the message header.

8 . The apparatus according to claim 4 , wherein the specific message is a radio resource control message, a location positioning protocol message or a non-access stratum message.

9 . A method comprising:

receiving by a control-plane network entity a service request from a user equipment;

selecting by the control-plane network entity at least one control plane routing identifier for the user equipment, the control plane routing identifier corresponding to one of a plurality of control plane entities in a network;

sending by the control-plane network entity the at least one control plane routing identifier to the user equipment;

receiving a message comprising a lower layer protocol header comprising the control plane routing identifier; and

routing the message to the one of the control plane entities based on the control plane routing identifier.

10 . An apparatus comprising:

at least one processor; and

at least one memory, said at least one memory stored with computer program code thereon, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform:

sending a service request to a control-plane network entity;

receiving at least one control plane routing identifier from the control-plane network entity, the control plane routing identifier corresponding to one of a plurality of control plane entities in a network;

storing the at least one control plane routing identifier to a memory;

generating a message comprising a lower layer protocol header comprising the control plane routing identifier to cause the message to be routed to the one of the control plane entities based on the control plane routing identifier.

11 . The apparatus according to claim 10 , wherein the apparatus is further caused to perform:

receiving an indication of at least one activated signalling radio bearer for carrying control plane messages.

12 . The apparatus according to claim 10 , wherein the apparatus is further caused to perform:

including at least one control plane routing identifier in one or more specific messages and/or triggering conditions.

13 . The apparatus according to claim 10 , wherein the apparatus is further caused to perform:

receiving a plurality of control plane routing identifiers each associated with a specific message and/or triggering condition.

14 . The apparatus according to claim 13 , wherein the specific message is a radio resource control message.

15 . The apparatus according to claim 10 , wherein the apparatus is further caused to perform at least one of the following:

retrieving the at least one control plane routing identifier explicitly from the message;

retrieving an implicit indication of the at least one control plane routing identifier from the message.

16 . The apparatus according to claim 10 , wherein the apparatus is further caused to perform:

preparing a message for transmission to the network entity; and

associating the control plane routing identifier with the message.

17 . The apparatus according to claim 10 , wherein the apparatus is further caused to perform:

preparing a message for transmission to the network entity, wherein the message or a part of the message is intended to multiple different entities in the network; and

associating a plurality of control plane routing identifiers with the message.

18 . The apparatus according to claim 10 , wherein the apparatus is further caused to perform:

storing the one or more control plane routing identifiers into a memory and information of association between the one or more control plane routing identifiers and the one or more signalling radio bearers.

19 . The apparatus according to claim 18 , wherein the apparatus is further caused to perform:

retrieving from the memory one or more of the control plane routing identifiers and information of one or more signalling radio bearers associated with the retrieved one or more control plane routing identifiers.