opensand team mailing list archive

[Julien BERNARD <jbernard@xxxxxxxxxxxxxxxxxxx>]

Hi Andrei,
> While  carrying  out a series of experiments I faced a problem when at
> some point Satellite Terminal stops working.
> The  testbed  topology  is  presented in the attached file. I generate
> multiple  traffic  flows (1 to 9) from  the  Sender  to  the  Receiver  in the
> direction  from GW to ST using iperf with MSS = 1400 bytes. The buffer
> of the GW (max_fifo) reduced to the value of 2500.
> At  some  point  of the experiments (after 40-100 seconds form flow(s)
> start)  the  ST  stops  processing  traffic (sometimes ST indicator in
> OpenSand  Manager  turns red, sometimes it's still green but TCP flows
> don't flow).

I tried to reproduce your problem in your conditions but among many 
tests I only encounter a crash a couple of times and this is not enough 
to investigate.

My tests:
 - I configure GW fifo size to 2500 and  start OpenSAND
 - I launch 9 or more iperf flows with the command "iperf -c 
192.168.19.1 -p 3004 -M 1400 -t 500 -m" in a workstation behind the GW
Am I missing something ? Do you have a problem for each test or is it 
random ?

> In  the  core.log  I  see  the  following  errors after which ST stops
> working:
>
> Jul 24 15:28:40 router st: [encap] [Mpeg.cpp:deencapsulate():193] ERR: [Mpeg::Context::deencapsulate] cannot create a burst of packets, drop packet
> Jul 24 15:28:42 router st: [encap] [Mpeg.cpp:deencapMpeg():515] ERR: [Mpeg::Context::deencapMpeg] MPEG frame(s) lost (MPEG CC = 12, CTXT CC = 8), reset context, sync on PUSI
> Jul 24 15:28:42 router st: [encap] [Mpeg.cpp:deencapMpeg():515] ERR: [Mpeg::Context::deencapMpeg] MPEG frame(s) lost (MPEG CC = 15, CTXT CC = 2), reset context, sync on PUSI
> Jul 24 15:28:43 router st: [dvb_rcs_tal] [bloc_dvb_rcs_tal.cpp:connectToQoSServer():1138] [Tal][BlocDVBRcsTal::connectToQoSServer] service on TCP/12000 is not available
> Jul 24 15:28:44 router st: [encap] [Mpeg.cpp:deencapMpeg():536] ERR: [Mpeg::Context::deencapMpeg] PUSI not set in current MPEG frame, drop it
> .............................
> Jul 24 15:28:56 router st: [encap] [../../src/common/IpPacketHandler.h:build():89] ERR: [IpPacketHandler::build] cannot get IP version
> Jul 24 15:28:56 router st: [encap] [Ule.cpp:deencapUle():397] ERR: [Ule::Context::deencapUle] cannot create a IP packet, drop the ULE packet
> Jul 24 15:28:56 router st: [encap] [Ule.cpp:deencapsulate():191] ERR: [Ule::Context::deencapsulate] cannot create a burst of packets, drop packet
> Jul 24 15:28:56 router st: [encap] [../../src/common/IpPacketHandler.h:build():89]
The errors seems to be in the encapsulation plugins, could you try with 
GSE on forward link instead of MPEG/ULE ?
You may have to install libopensand-gse-encap-plugin on hosts and 
libopensand-gse-encap-plugin-manager on manager.


> Could you please tell me what can cause this problem?

I think there is a bug in OpenSAND appearing at high throughput but I 
need a way to reproduce it easily in order to fix it.

Best regards,

--
Julien BERNARD