The SP1 seems fixed the problem perfectly! (although I don't know what was the problem;p)  
My script runs whole night for more than 600 times now and all NICs are still alive working hard.

Many many thanks!  

Yours
Jay

> Please can you try this with the latest driver in 6.5.0 SP1, available on
> our web site.
> 
> 
> 
> On 12-06-21 7:14 AM, "y cheng" <community-noreply@qnx.com> wrote:
> 
> >Hi all,
> >
> >I need your help finding out what could be the problems causing the
> >io-pkt-v4-hc crash occationally when I issue a "ifconfig en0 down"
> >command on QNX 6.5.0. All clues are appreciated!
> >
> >Some details of the setting up.(Please let me know if you need more
> >information):
> >
> >There are two QNX PCs(works as 1+1 backup). Each QNX PC has two NICs (en0
> >and en1); one of the two NIC (en1) on each PC is used to connect with the
> >other PC's en1 running mqueue with qnet protocol. The other NICs (en0) on
> >each PC are configured with the same MAC/IP addresses (one PC en0 is down
> >and another PC en0 is up) to work as 1+1 backup. Both en0 are connected
> >with a third PC to provide service. I am running rp-pppoe 3.20(built from
> >source) server on both QNX PCs and pppoe client on the third PC. I need
> >to test hot swap between two QNX PCs  (basically, move the established
> >pppoe sessions from one PC to another without redial, both PCs have the
> >same pppoe session information before moving).
> >
> >It works well most of the time. After I "ifconfig en0 down" one PC and
> >"ifconfig en0 up" another PC, the pppoe sessions on the second PC take
> >over by redoing the LCP negotiation automatically. But some time, when
> >issuing the ifconfig en0 down on one PC and issuing the ifconfig en0 up
> >on another(down is about 300ms earlier than the up command), the one
> >which ifconfig en0 down is issued reports "bad file descriptor" for the
> >socket or "no such process" errors. And the io-pkt-v4-hc disappeared from
> >the "ps -A" list. When I checked by pidin mem, neither io-pkt-v4-hc nor
> >devn-rtl.so/devnp-shim.so/devn-rtl.so/lsm-qnet.so exist. nicinfo is
> >empty. ifconfig list is empty too. I have to reload all NIC drivers or
> >restart the OS to recover this.
> >
> >It does not happend all the time, some time it happens if I swap once;
> >some time I need to do swap more than 100 times to make it happen.
> >
> >Thanks a lot in advance!
> >
> >Yours
> >Jay
> >
> >
> >
> >_______________________________________________
> >
> >Networking Drivers
> >http://community.qnx.com/sf/go/post93804
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