diff options
| author | Daniel Willmann <dwillmann@sysmocom.de> | 2020-04-09 17:43:56 +0200 |
|---|---|---|
| committer | Pau Espin Pedrol <pespin@sysmocom.de> | 2020-08-17 19:11:19 +0200 |
| commit | 624b5cdc221ebb254b6091bacd4630b8a9339290 (patch) | |
| tree | 9ea1c94465a80d4e0a454d552e9e6e1394803644 /doc | |
| parent | d6daf726a2176539b07a6bce41b91385f498f9e0 (diff) | |
osmo-bts-trx: Use much lower clock advance values towards PCU and TRX
osmotrx fn-advance (which is the clock_advance variable here) and
osmotrx rts-advance together make up the minimum delay the BTS can react
to a channel request, etc.
The default of 20 are around 92ms which is clearly too much. With
modern hardware and using SCHED_RR a lower value should not be an issue.
See OS#4487 for some related measurements on more CPU-limited devices like a
LimeNet-micro3.
Fixes: OS#4487
Fixes: SYS#4885
Related: SYS#4881
Change-Id: I7da3d0948f38e12342fb714b29f8edc5e9d0933d
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/manuals/chapters/bts-models.adoc | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/doc/manuals/chapters/bts-models.adoc b/doc/manuals/chapters/bts-models.adoc index 495571fa..5cb04616 100644 --- a/doc/manuals/chapters/bts-models.adoc +++ b/doc/manuals/chapters/bts-models.adoc @@ -270,8 +270,7 @@ on a remote host will inevitably require a higher fn-advance than running it on the same machine, where the UDP packets are just passed over the loopback device. -The default value for `fn-advance` is 20 (corresponding to 92 -milliseconds). +The default value for `fn-advance` is 2 (corresponding to 9.2 milliseconds). ===== `osmotrx rts-advance <0-30>` @@ -290,7 +289,7 @@ reported on L1SAP to higher layers will be computed as follows: N + fn-advance + rts-advance -The default value of `rts-advance` is 5 (corresponding to 23 milliseconds). +The default value of `rts-advance` is 3 (corresponding to 14 milliseconds). Do not change this unless you have a good reason! ===== `osmotrx rx-gain <0-50>` |