Socket Server Reference

This topic provides a summary of related documentation for the ESock APIs.

Socket Server APIs:

Server session APIs   Header Description



RSocketServ establishes and reserves resources for the base communication session to the socket server. All other client interfaces require a valid session to be opened

RSocketServ Subsession APIs



End point for all socket-based communications.



Makes host name resolution queries.



Used to startup and manage active connections. It is possible to start a connection either implicitly, via the RSocket or RHostResolver APIs, or explicitly via the RConnection API. The RConnection creates a default subconnection.

RConnection API Reference



Used to organise channels within a connection and manage Quality of Service. Multihoming-aware applications must use this API. Only valid in the context of an RConnection.



Interface for network database access.



Provides an interface to resolve service names and ports.




Provides access to the Comms Management Plane, including Access Point queries.

Bearer Mobility APIs

Bearer mobility APIs Header Description



Comms Mobility API extension for application client running an Active Scheduler.



Comms Mobility API extension for application client not running an Active Scheduler.



Interface to be implemented by the application client to support mobility API extension. See Bearer Mobility Client.

How APIs related to the 3-Plane Comms Architecture.

Figure 1. Figure 1 - How ESock APIs related to the 3-Plane Comms Architecture

The Sockets Client API also defines a number of support classes used in conjunction with the above interfaces. These encapsulate:

  • Addresses: a base address class TSockAddr is defined. Specific protocol address classes are derived from this. Each address can be identified by its Protocol Family, an integer which identifies protocol suites from others.

  • Resolution queries: queries made through RHostResolver objects are packaged in TNameEntry descriptors. These are packages for TNameRecord objects that contain TSockAddr objects to pass in addresses.

  • Protocol information: a comprehensive description of a protocol’s capabilities and properties can be dynamically obtained through the TProtocolDesc class. Capabilities are identified by constants.

  • Endian issues: BigEndian, LittleEndian, and ByteOrder can be used to order integers to and from network order.

RSubConnection Events

CSubConGenEventDataClientJoined, CSubConGenEventDataClientLeft

These two events derive from CSubConGenEventDataClientBase, which provides the functionality for both. The source and destination end points of the data client are presented with this event, along with the IAP ID of the connection on which it was created.


Both generic and extension sub-connection events derive from this class. The rules for generic and extension events are the same as for parameter sets. That is, a generic event MUST be able to be understood by all technologies.

The IsGeneric() method identifies whether the event is generic.

The GroupId() method returns the UID of the factory that contains the event, and Id() returns the class type Id within that factory. These two pieces of information comprise the STypeId of the event.


Notification of this event occurs after a request to SetParameters() has been made and negotiation with the network has been completed. A notification will be received for each family contained in the parameter bundle that was negotiated successfully. This event presents a generic set and zero or more extension sets (providing they are supported by the underlying sub-connection provider technology) of the parameter family identified by the Id returned from GetFamily().


Notification of this event occurs after a request to SetParameters() has been made and negotiation with the network has failed for some reason. It could be an error within the handset software/configuration, or that the network could not provide the acceptable (minimum) level of QoS. The reason for failure and the parameter family are presented by the accessor methods Error() and FamilyId(). Like the CSubConGenEventParamsGranted event, a notification for CSubConGenEventParamsRejected is received for each family in the parameter bundle that could not be negotiated successfully.


This event occurs when the properties of a parameter family has been renegotiated due to some event on the network. It is not sent in response to a request to change the properties. The change could be the result of an error or just that the level of QoS has improved/worsened. If a new set of parameters are available they’ll be presented as with the CSubConGenEventParamsGranted event. The error status is presented via the Error() method.


This event occurs when the underlying sub-connection has been lost. This could be due to request for it to be closed, or some error on the network. The error status is presented via the Error() method.

RSubConnection QoS Parameters


Parameter Description Directions


Bandwidth the client requires

Uplink / Downlink

Maximum Burst Size

Maximum size of a burst of data the client can handle

Uplink / Downlink

Average Packet Size

Average packet size required (e.g. codec use)

Uplink / Downlink

Maximum Packet Size

Maximum packet size the client can handle

Uplink / Downlink


Acceptable Delay/Latency

Uplink / Downlink

Delay Variation

Acceptable variation in delay (also known as jitter)

Uplink / Downlink


Relative priority the client expects to give this channel compared to it’s other channels

Uplink / Downlink

Header mode

Specify whether the header size should be calculated by the QoS module or specified by the client. Default is to let the QoS module calculate it.



Identity of a “well known” set of QoS Parameters.


If an extension parameter set is added to the family that contains conceptually identical parameters to those in the generic set, it is recommended that you set both instances (generic and extension) of those parameters.

CSubConQosIPLinkR99ParamSet / CSubConQosR99ParamSet

Getter and setter methods are provided for each parameter.

Note: The constants used for it are KSubConIPParamsUid and KSubConQosIPLinkR99ParamsType.

The following parameter sets are available in Symbian platform.


It inherits from the release 4/99 set CSubConQosR99ParamSet. Although it is possible to add both this parameter set and the R4/R99 one, it is not necessary and should not be done.


This class contains the IM CN Signalling Indicator flag.

Test programs