10.1.0 General remark about EPS bearer contexts and PDP contexts
27.0073GPPAT command set for User Equipment (UE)Release 18TS
According to 3GPP TS 23.401 [82], there is a 1 to 1 mapping between active EPS bearer context and active PDP context:
– An active default EPS bearer context is associated with an active non secondary PDP context.
– An active dedicated EPS bearer context is associated with an active secondary PDP context.
In consequence to the implicit logical relation between EPS PDN connection and its associated Default EPS Bearer, hereafter a same non secondary PDP context identifier <p_cid> can be used to refer either an EPS PDN connection context or its associated Default EPS Bearer context.
As dedicated EPS bearer contexts are activated by the network, the network can then activate a new dedicated EPS bearer or modify an existing one to fulfil the request. For bearer resources activated by the network a context identifier is allocated by the MT/TA.
For easy reading the term PDP context is used for PDP contexts in UMTS/GPRS as well as PDN/default EPS bearers and traffic flows in EPS.
The feature "initial PDP context" may be supported and is a manufacturer specific option. For this option, the context with <cid>=0 (context number 0) is defined upon startup and does not need to be created with the +CGDCONT command. The initial PDP context has particular manufacturer specific default settings disassociated with any other default settings of +CGDCONT. When in E-UTRAN or according to the AT-command +CIPCA in GERAN and UTRAN, the initial PDP context is automatically activated by the MT following a successful registration to the network. If all active contexts are deactivated, the initial PDP context can be (re)established. This is manufacturer specific and depends on the current RAT as well as how the active contexts are deactivated.
NOTE 1: Care must be taken to secure that repetitive PDP context activations / deactivations are not performed and that PDP contexts are not activated in situations where it is a determined choice by the terminal or the network to discontinue connectivity. Examples of such deliberate discontinuation of connectivity are the AT-commands +CGATT=0 or +CGACT=0, receipt of a detach request from the network with "re-attach not required" or when all PDP contexts are deactivated by the network.
Table 10.1.0-1: AT commands/results applicable for EPS
(equivalence between PDP context / PDN Connection or Default EPS Bearer)
|
AT commands |
Comments |
|
+CGDCONT |
Used to define PDN connection for EPS. |
|
+CGACT |
Used to activate a bearer resource for EPS. |
|
+CGCONTRDP |
Used to show dynamically allocated PDN parameters. |
|
+CGEV: xxx … |
Used to indicate EPS bearers operations status. |
Table 10.1.0-2: AT commands/results applicable for EPS
(equivalence between PDP context / EPS Bearer Resources)
|
AT commands |
Comments |
|
+CGACT |
Used to activate a modification of a PDP context or EPS bearer resource. |
|
+CGDSCONT |
Used to define EPS Bearer Resource for a specific PDN for EPS. |
|
+CGSCONTRDP |
Used to show dynamically allocated EPS Bearer Resource parameters. |
|
+CGCMOD |
Used to request a modification of a PDP context or EPS Bearer Resource. |
|
+CGTFT |
Used to define a Traffic Flow Template for a PDP context or a Traffic Flow Aggregate for an EPS bearer resource. |
|
+CGTFTRDP |
Used to show the network assigned Traffic Flow Template for an EPS bearer resource. |
|
+CGEQOS |
Used to define the EPS bearer resource Quality of Service parameter. |
|
+CGEQOSRDP |
Used to show the network assigned EPS QoS parameters for an EPS bearer resource. |
|
+CGEV: xxx … |
Used to indicate EPS PDN connection and bearer resources operations status |
Table 10.1.0-3: AT commands applicable for EPS
|
AT commands |
Comments |
|
+CGATT |
Used to attach/detach the MT from the Packet Domain service. |
NOTE 2: The above is not a complete list of AT commands for EPS but only those applicable to PDN connections and EPS bearer resources.