[ros-users] image transport saturating network

Dan Lazewatsky lazewatskyd at cse.wustl.edu
Mon Apr 12 20:03:36 UTC 2010


So far no luck messing with fragmentation threshold and RTS threshold. 
They default to 2346 and 2347 respectively, and I've tried bumping them 
both (and individually) way down with no effect.

ifconfig on the robot doesn't show any errors, dropped packets or overruns.

-Dan

On 4/9/10 4:49 PM, Blaise Gassend wrote:
> Well, you defnitely do have some long packets in there, so the steps I
> described before could help. Can you get error counts from your wireless
> interface?
>
> On Fri, 2010-04-09 at 16:06 -0500, Dan Lazewatsky wrote:
>    
>> Here's some more:
>>
>> 16:03:05.393873 00:16:44:c6:4f:f4 (oui Unknown)>  00:26:08:e9:8a:bc (oui
>> Unknown), ethertype IPv4 (0x0800), length 1514:
>> toil.robots.cse.wustl.edu.53552>  192.168.1.115.49680: .
>> 1130888:1132336(1448) ack 1 win 108<nop,nop,timestamp 5842447 497191153>
>> 16:03:05.393892 00:26:08:e9:8a:bc (oui Unknown)>  00:16:44:c6:4f:f4 (oui
>> Unknown), ethertype IPv4 (0x0800), length 66: 192.168.1.115.49680>
>> toil.robots.cse.wustl.edu.53552: . ack 1133784 win 65535
>> <nop,nop,timestamp 497191169 5842447>
>> 16:03:05.394168 00:16:44:c6:4f:f4 (oui Unknown)>  00:26:08:e9:8a:bc (oui
>> Unknown), ethertype IPv4 (0x0800), length 1514:
>> toil.robots.cse.wustl.edu.53552>  192.168.1.115.49680: .
>> 1132336:1133784(1448) ack 1 win 108<nop,nop,timestamp 5842456 497191153>
>> 16:03:05.394182 00:26:08:e9:8a:bc (oui Unknown)>  00:16:44:c6:4f:f4 (oui
>> Unknown), ethertype IPv4 (0x0800), length 66: 192.168.1.115.49680>
>> toil.robots.cse.wustl.edu.53552: . ack 1133784 win 65535
>> <nop,nop,timestamp 497191169 5842456>
>> 16:03:05.394233 00:26:08:e9:8a:bc (oui Unknown)>  00:16:44:c6:4f:f4 (oui
>> Unknown), ethertype IPv4 (0x0800), length 66: 192.168.1.115.49680>
>> toil.robots.cse.wustl.edu.53552: . ack 1129440 win 65535
>> <nop,nop,timestamp 497191168 5842437>
>> 16:03:05.394353 00:26:08:e9:8a:bc (oui Unknown)>  00:16:44:c6:4f:f4 (oui
>> Unknown), ethertype IPv4 (0x0800), length 66: 192.168.1.115.62595>
>> toil.robots.cse.wustl.edu.ssh: . ack 752 win 33304<nop,nop,timestamp
>> 497191168 5842439>
>> 16:03:05.394458 00:26:08:e9:8a:bc (oui Unknown)>  00:16:44:c6:4f:f4 (oui
>> Unknown), ethertype IPv4 (0x0800), length 66: 192.168.1.115.49680>
>> toil.robots.cse.wustl.edu.53552: . ack 1130888 win 65535
>> <nop,nop,timestamp 497191168 5842447>
>> 16:03:05.394563 00:26:08:e9:8a:bc (oui Unknown)>  00:16:44:c6:4f:f4 (oui
>> Unknown), ethertype IPv4 (0x0800), length 66: 192.168.1.115.49680>
>> toil.robots.cse.wustl.edu.53552: . ack 1133784 win 65535
>> <nop,nop,timestamp 497191169 5842447>
>> 16:03:05.395265 00:26:08:e9:8a:bc (oui Unknown)>  00:16:44:c6:4f:f4 (oui
>> Unknown), ethertype IPv4 (0x0800), length 98: 192.168.1.115>
>> toil.robots.cse.wustl.edu: ICMP echo request, id 12823, seq 5952, length 64
>>
>> -Dan
>>
>> On 4/9/10 3:56 PM, Blaise Gassend wrote:
>>      
>>>> The man file isn't particularly useful for figuring out how what the
>>>> output means, so here is a few lines:
>>>>
>>>> 15:04:57.045705 IP toil.robots.cse.wustl.edu.53552>
>>>> 192.168.1.115.49680: . 931064:932512(1448) ack 1 win 108
>>>> <nop,nop,timestamp 4970372 497156321>
>>>> 15:04:57.045710 IP 192.168.1.115.49680>
>>>> toil.robots.cse.wustl.edu.53552: . ack 931064 win 33304
>>>> <nop,nop,timestamp 497156335 4970352>
>>>> 15:04:57.045711 IP 192.168.1.1.http>   192.168.1.115.49706: P 1:351(350)
>>>> ack 597 win 6556<nop,nop,timestamp 172066583 497156334>
>>>> 15:04:57.045777 IP 192.168.1.115.49680>
>>>> toil.robots.cse.wustl.edu.53552: . ack 933960 win 33304
>>>> <nop,nop,timestamp 497156335 4970372>
>>>> 15:04:57.045809 IP 192.168.1.115.49706>   192.168.1.1.http: . ack 351 win
>>>> 33129<nop,nop,timestamp 497156335 172066583>
>>>>
>>>>          
>>>>> Have you tried using compressed image transports?
>>>>>
>>>>>            
>>> Strange, I have never seen tcpdump not print packet lengths. Try adding
>>> -e.
>>>
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