If lifetime expires of queued LLC frames, they are discarded. The number
of discarded frames and the sum of their octets are reported to SGSN
via LLC-DISCARDED message.
The lifetime can be overridden via VTY. The value can be centi-seconds
or "infinite".
In order to do downlink assignment during uplink TBF, the content
resolution must be completed. It is completed when the first Packet
Uplink Ack/Nack message is transmitted to the mobile.
It turned out that the final ack flag may not be set, but all packets
have been acknowledged. This patch will finish transfer in case all
blocks are acknowledged.
The slot must be the control channel TS, which is selected by the
allocation algorithm. The MS must be able to respond at this TS.
The counter to trigger polling is incremented until polling has to be
performed. Then the counter stops. When the transmission of data block is
requested on control channel TS, the counter is reset. The counter-value
is also used to poll immediately when the transmission has finished.
In order to send control blocks to MS and receive control blocks from MS
(polling), it is required to select one timeslot that the MS must be
able to send and receive. The allocation algorithm must take care of
selecting that slot.
The new data structure is required to define slot/TFI assigment for MS
with multislot capability.
Now there are two lists for TBFs: uplink and downlink. It is possible to
have different TBFs with same TFI in the same direction, as long as they
are assigned on different timeslots.
See tbf.txt for description.
Note: This does not implement any multislot support. It defines the new
data structure. Currently only the first slot is assigned.
Merge is based on jolly_new branch with two modifications.
1. Modified PCU L1 interface.
pcu_l1_if.cpp - common functions for tx and rx messages on L1 interface.
sysmo_sock.cpp - SYSMO-PCU socket functions.
openbts_sock.cpp - OpenBTS-PCU socket functions.
pcuif_proto.h - L1 interface's primitives.
2. Modified encoding of RLC/MAC Control messages, now we use structures and encode_gsm_rlcmac_downlink() function for encode control blocks (without hand-coding).
Only when using LOGL_DEBUG, every detailled information is displayed.
When using LOGL_INFO, a summary of the process is displayed.
When using LOGL_NOTICE, only errors and warnings like timeouts
or invalid received informations are displayed.
When using LOGL_ERROR, only local error like software errorss are
displayed.
The pseudo length may not include the rest-octets, so it stays compatible
to non-GPRS phones.
At pcu_l1_if.c (OpenBTS) no pseudo length is given, so the frame is
only 22 bytes long. I could not test if it works.
These informations provide RAI, timers, counters and other attributes to
the BSSGP and RLC/MAC processes.
The attributes are stored in gprs_rlcmac_bts global structure.
It uses history buffer and sends ack/nack control messages about received
blocks. It defragments the blocks and forwards them to upper layer. It
does content resolution and ignores other MS. It sends final ACK after
all blocks have been sucessfully received. Timers are used to detect
loss of uplink, and repeat lost final ACK.
Andreas Eversberg