From 94f880ad23c8ac7e6650226fdf22088d7ffb18d8 Mon Sep 17 00:00:00 2001 From: Cedric Roux <cedric.roux@eurecom.fr> Date: Mon, 10 Apr 2017 17:31:21 +0200 Subject: [PATCH] bugfix: increase RLC UM header size The constant RLC_UM_SEGMENT_NB_MAX_LI_PER_PDU is set to 24. This is too low. Running a downlink TCP iperf with a 10MHz or 20MHz cell leads to lots of the following warning in the log: [RLC][W][SN 792] Bad RLC header! Discard this RLC PDU (size=618) The problem is that the uplink RLC PDU contains a lot of TCP ack. We can see much more than 24 of them. The RLC layer is not happy and discards the PDU. Putting 256 for RLC_UM_SEGMENT_NB_MAX_LI_PER_PDU (arbitrarily chosen, big but not too big) solves the problem, at least for 10MHz. --- openair2/LAYER2/RLC/UM_v9.3.0/rlc_um_constants.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/openair2/LAYER2/RLC/UM_v9.3.0/rlc_um_constants.h b/openair2/LAYER2/RLC/UM_v9.3.0/rlc_um_constants.h index 2d0a875edb..acd94fa205 100644 --- a/openair2/LAYER2/RLC/UM_v9.3.0/rlc_um_constants.h +++ b/openair2/LAYER2/RLC/UM_v9.3.0/rlc_um_constants.h @@ -53,7 +53,7 @@ // UM_Window_Size = 512 when a 10 bit SN is configured and UM_Window_Size = 0 // when the receiving UM RLC entity is configured for MCCH or MTCH. // li field (values shifted 1 bit left) -# define RLC_UM_SEGMENT_NB_MAX_LI_PER_PDU 24 +# define RLC_UM_SEGMENT_NB_MAX_LI_PER_PDU 256 //---------------------------------------------------------- // Events defined for state model of the acknowledged mode entity /** Internal event defined for state model of the RLC UM. */ -- GitLab