[Planetlab-devel] Wireless Mesh and MyPLC

[WangITR, Wei]

Hi Marc,

The system crashes either just after I type "ping ..." or at most after
receiving one reply. The following are the dump messages (omit the
address and return values) after the system crashes (only the last
screen since the system is not responsive). It actually varies every
time. Sorry I cannot provide more because I copied them by hand ...

Ieee80211_xmit
_ip_conntrack_confirm
Ip_finish_output2
Copy_skb_header
Qdisc_restart
Dev_queue_xmit
Neigh_resolve_output
Ip_push_pending_frames
Raw_sendmsg
Inet_sendmsg
Sock_sendmsg
Autoremove_wake_function
Copy_from_user
Verify_iovec
Sys_sendmsg
Recalc_task_prio
Schedule
Schedule_timeout
Sock_pull
Do_pollfd
Sys_socketcall
Sys_gettimeofday
Syscall_call


Wei


-----Original Message-----
From: Marc E. Fiuczynski [mailto:mef at CS.Princeton.EDU] 
Sent: Tuesday, January 30, 2007 1:38 PM
To: WangITR, Wei
Cc: Chan, Winson C; devel at lists.planet-lab.org
Subject: Re: [Planetlab-devel] Wireless Mesh and MyPLC

Hello Wei and Winson,

You are right.  When VNET is not running the "old" nodemanager software 
fails, as it expects to interact with VNET.  And when it fails pl_conf 
and other slices do not get created.

Winson mentioned that VNET crashes even when sending just a ping message

via your ported WiFi/mesh driver.  This presumably is due to some 
strange interaction between VNET and your driver.  Could you give us 
more information on the VNET crash?  Does the oops by any chance 
indicate a call stack or the function within VNET that is causing the
crash?

On a different note, the PL team @ Princeton is working hard towards a 
MyPLC 1.0 (and PlanetLab 4.0) release.  It looks like we will either 
settle with a kernel based on 2.6.16.xx.  The benefits of the new 
release will be (the beginning of) support for Federation, which was 
something that John V. mentioned would be of use to your specific 
project.  The release will also contain a rewritten node manager, which 
will be easier for us to fix as we do not plan to make fixes or 
enhancements to the old node manager.

It might be a good idea to chat on the phone sometime in the not to 
distant future to re-sync between your efforts, our efforts, and the 
efforts of others who are enabling MyPLC with WiFi nodes.

Marc



WangITR, Wei wrote:
> Hi Marc,
> 
> We tried to disable vnet via " chkconfig --del vnet ". But no slice
> (even the pl_conf) will be created after node boots. Is it possible to
> create slices without VNET?
> 
> 
> Wei
> 
> -----Original Message-----
> From: Marc E. Fiuczynski [mailto:mef at CS.Princeton.EDU] 
> Sent: Tuesday, January 30, 2007 1:11 PM
> To: Chan, Winson C
> Cc: devel at lists.planet-lab.org; WangITR, Wei
> Subject: Re: [Planetlab-devel] Wireless Mesh and MyPLC
> 
> Winson,
> 
> You will need to provide more info on the crash, as I don't know what 
> might cause VNET to fail.  To the best of my knowledge, VNET is
agnostic
> 
>   to the type of device you are using for networking.  Of course, it 
> does care about protocols.  Are you using something other than IPv4
for 
> Layer-3 or some other non-standard/new Layer-4 protocol?
> 
> You can certainly disable VNET.  You can do so by de-installing its
rpm 
> (rpm -e vnet) or by disabling it from being invoked upon boot by using

> chkconfig (chkconfig --del vnet).
> 
> Marc
> 
> 
> Chan, Winson C wrote:
> 
>>Marc,
>>
>> 
>>
>>This is a follow up to the wireless mesh integration with MyPLC.  We 
>>ported our wireless mesh software to run on the MyPLC 0.4 RC1 kernel 
>>(2.6.12).  Whenever our wireless mesh software is running, VNET
> 
> crashes 
> 
>>the system (sometimes after receiving the first ping reply via the 
>>wireless link).  If we disable our wireless mesh software, the node
> 
> runs 
> 
>>fine and we are able to create slices.  Do you have any idea what's 
>>causing VNET to crash?  Also, is it possible to circumvent this, say 
>>disabling VNET?
>>
>>
>>Thanks.
>>Winson
>>
>> 
>>
>>
>>
> 
>
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> 
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