What is PDP Context and whats the difference between Primary and Seconday PDP Context?
Please refer to the PDP Context Tutorial in Tutorials Section.
Can you please tell me what AT commands to use to Secondary PDP Context activation? We use AT+CGATT for Primary PDP Context activation.
The following AT commands are generally used for PDP Context activation:
Format: AT+CGDCONT=<cid>,<PDP_type>,[<APN>,[<pdp_addr>]]
Example 1: AT+CGDCONT=1,”IP”
Example 2: AT+CGDCONT=1,”IP”,”internet”
Where
<cid>: Local PDP Context Identifier. A numeric parameter which specifies a
particular PDP context definition and can be quoted in other PDP context related
commands as reference (e.g. in AT+CGDSCONT, AT+CGTFT, AT+CGEQREQ,
AT+CGACT, etc.)
<PDP_type>: Packet Data Protocol Type. A string parameter, typically “IP” is used
(for IPv4)
<APN>: Access Point Name. A string parameter (case insensitive) which is used to
select an access point in the GGSN. If the value is null (“”) or omitted, the
subscribed value will be requested.
<PDP_addr>: PDP Address. A string parameter that identifies the MT in the
address space applicable to the PDP. In case of IP PDP type this means the IP
address. If the value is null or omitted the TE may provide the address (which will
be used at PDP context activation) or a dynamic address will be requested and
assigned by the GGSN. Typically dynamic IP address assignment is used
(dynamic HPLMN PDP address).
For Secondary PDP Contexts
Format: AT+CGDSCONT=<cid>,<p_cid>
Example 1: AT+CGDSCONT=2,1
Example 2: AT+CGDSCONT=3,1
Where
<cid>: Local PDP Context Identifier. A numeric parameter which specifies a
particular secondary PDP context definition and can be quoted in other PDP
context related commands as reference (e.g. in AT+CGTFT, AT+CGEQREQ,
AT+CGACT, etc.)
<p_cid>: Primary PDP Context Identifier. The secondary PDP context will be
associated with this (already defined) primary PDP context.
Note:
- The primary PDP context with the identifier has to be defined in
advance (with the use of AT+CGDCONT)
- Context identifier(s) already assigned to primary context(s) can not be used
for the secondary context(s) (i.e. the context identifier pool is common for all the
primary and secondary contexts)
References:
3GPP TS 27.007: AT command set for User Equipment (UE)