Bug #1759
Wrong calculation of DL window size for DL assignment
30%
Description
Hi,
When we create DOWNLINK TBF without existing UPLINK TBF i.e DL assignment on PCH case, The calculation of window size is found to be incorrect.
Description:
4 time slots is configured for DL and osmo-pcu.cfg is configured as window-size 64 104.
When we try to do IPERF in DL direction, PCU allocates window-size as 160 but configures 4 time slots
as seen by PCU VTY. Below is the result of VTY output.DL TBFs
TBF: TFI=0 TLLI=0xf73d2ece (valid) DIR=DL IMSI=901555000001280
created=1095 state=0000000a 1st_TS=4 1st_cTS=6 ctrl_TS=6 MS_CLASS=0/1
TS_alloc=4 5 6! 7 CS=MCS-9 WS=160 V(A)=12 V(S)=12 nBSN=138But we see proper calculation of window-size when DL assignement is done on PACCH. as seen by VTY interface belowDL TBFs
TBF: TFI=0 TLLI=0xf73d2ece (valid) DIR=DL IMSI=901555000001280
created=1095 state=0000000a 1st_TS=4 1st_cTS=6 ctrl_TS=6 MS_CLASS=0/1
TS_alloc=4 5 6! 7 CS=MCS-9 WS=480 V(A)=138 V(S)=139 nBSN=138Thanks,
Aravind Sirsikar
Related issues
History
#7 Updated by msuraev 7 months ago
- Related to Feature #1533: Separate the window handling from the TBF more clearly added
#8 Updated by msuraev 7 months ago
- Status changed from New to In Progress
- % Done changed from 0 to 20
Related gerrit 5355, 5336-5341 are under review. Remaining parts: clearly differenciate between CCCH and PACCH assignment, figure out whyit makes a difference to window size calculations and test with different window sizes settings and available channels.
#12 Updated by msuraev 6 months ago
The window size parameter in vty defined as follows:
window-size <0-1024> [<0-256>] Window size configuration (b + N_PDCH * f) Base value (b) Factor for number of PDCH (f)
So the configuration window-size 64 104 means that WS(1TS) = 64 + 1 * 104 = 168 and WS(4TS) = 64 + 4 * 104 = 480. By default f = 0.
#15 Updated by laforge 5 months ago
Hi Max,
On Mon, Feb 05, 2018 at 03:45:50PM +0000, msuraev [REDMINE] wrote:
In addition to difference between PACCH and CCCH, the TBF can be assigned via CCCH but configrmed via PACCH (see rcv_control_ack() function). This and the related #1524 makes it harder to reproduce this reliably.
would it be possible to disable certain variants as a temporary hack?
