Cellular Network Infrastructure » Radio Access Network » OsmoPCU

It is set by ts_PCUIF_INFO_default, so osmo-bts (TTCN3) is setting it through PCUIF:

t3193_10ms := 160,

It's been 100ms since at least:

commit 28f160e76c3c53029bc6e8de101b2d7ee26eea16
Author: Pau Espin Pedrol <pespin@sysmocom.de>
Date:   Thu Sep 5 14:48:35 2019 +0200

And also even a lot prior to that it was already defaulting to 100ms:

commit dfa563cd3bba9b6214289bc63c84b00f1f7676cd
Author: Andreas Eversberg <jolly@eversberg.eu>
Date:   Fri Jul 6 08:13:59 2012 +0200

    RLC/MAC process makes use from attributes, received from PCU socket

    For OpenBTS interface and BSSGP, fixed values are still used.

And being 1600 in TTCN3 is there since at least:

commit e1fd916b2110e0282f3d9320958c27876b7d91e1
Author: Harald Welte <laforge@gnumonks.org>
Date:   Mon Feb 18 19:47:53 2019 +0100

The problem seems to be that it's defined as 100ms by default in osmo-pcu since ever, but it is also defined as 1600ms in osmo-bts since ever (osmo-bts passes it to osmo-pcu throuygh PCUIF):

src/common/bts.c
159:            [RLC_T3193] = 160, /* 10ms */src/common/pcu_sock.c
289:    info_ind->t3193_10ms = rlcc->parameter[RLC_T3193];

Same in osmo-bsc:

src/osmo-bsc/bts_ipaccess_nanobts_omlattr.c
169:    buf[3] = 160;    /* T3193 (units of 10ms) */

src/osmo-bsc/bts.c
131:            [RLC_T3193] = 160, /* 10ms */

src/osmo-bsc/pcu_sock.c
167:    info_ind->t3193_10ms = rlcc->parameter[RLC_T3193];

So we need to find which is actually the best default value there, either 1600ms or 100ms (or some other value), and set it consistently everywhere.