LISA-U series - System Integration Manual
UBX-13001118 - R17
Advance information
Features description
Page 152 of 190
3.4
TCP/IP and UDP/IP
Via the AT commands it is possible to access the TCP/IP and UDP/IP functionalities over the Packet Switched data
connection. For more details about AT commands see the
u-blox AT Commands Manual
LISA-U modules support the Direct Link mode for TCP and UDP sockets. Sockets can be set in Direct Link mode
to establish a transparent end-to-end communication with an already connected TCP or UDP socket via serial
interface. In Direct Link mode, data sent to the serial interface from an external application processor is
forwarded to the network and vice-versa.
To avoid data loss while using Direct Link, enable HW flow control on the serial interface.
3.4.1
Multiple PDP contexts and sockets
Two PDP context types are defined:
“external” PDP context: IP packets are built by the DTE, the MT’s IP instance runs the IP relay function only
“internal” PDP context: the PDP context (relying on the MT’s TCP/IP stack) is configured, established and
handled via the data connection management packet switched data commands described in
u-blox AT
commands manual
Multiple PDP contexts are supported. The DTE can access these PDP contexts either alternatively through the
physical serial port, or simultaneously through the virtual serial ports of the multiplexer (multiplexing mode
MUX), with the following constraints:
Using the MT’s embedded TCP/IP stack, only 1 internal PDP context is supported. This IP instance supports
up to 7 sockets
Using only external PDP contexts, it is possible to have at most 3 IP instances (with 3 different IP addresses)
simultaneously. If in addition the internal PDP context is used, at most 2 external PDP contexts can be
activated
Secondary PDP contexts (PDP contexts sharing the IP address of a primary PDP context) are also supported.
Traffic Flow Filters for such secondary contexts shall be specified according to
3GPP TS 23.060
At most 2 secondary PDP contexts can be activated, since the maximum number of PDP contexts, both normal
and secondary, is always 3.
3.5
FTP
LISA-U modules support the File Transfer Protocol and Secure File Transfer Protocol functionalities via AT
commands. Files are read and stored in the local file system of the module. For more details about AT commands
see
u-blox AT Commands Manual
FTP files can also be transferred using FTP Direct Link:
FTP download
: the data coming from the FTP server is forwarded to the application processor via the serial
interface (for FTP without Direct Link mode the data is always stored in the module’s FFS)
FTP upload
: the data coming from the application processor via the serial interface is forwarded to the FTP
server (for FTP without Direct Link mode the data is read from the module’s FFS)
When Direct Link is used for a FTP file transfer, only the file content pass through the serial interface, whereas all
the FTP commands handling is managed internally by the FTP application.
Due to the limited size of module FFS, FTP direct link is useful to transfer files with size greater than FFS.
To avoid data loss while using direct link, enable HW flow control on the serial interface.
3.6
HTTP
LISA-U modules support Hyper-Text Transfer Protocol (HTTP/1.0) functionalities as an HTTP client is implemented:
HEAD, GET, POST, DELETE and PUT operations are available. The file size to be uploaded / downloaded depends
on the free space available in the local file system (FFS) at the moment of the operation. Up to 4 HTTP client
contexts can simultaneously be used.
