Qnet and Shared memory

QNX USERS QNX6 - OS
1

Problem 1-
how to specify the links and QoS policy in Qnet??
if i want to use serial link for message passing and use "Exclusive " QoS policy, how to specify it??

Problem -2: can shared memory of other node can be accessed???

2

QNET only works on ethernet link. For a serial link, you can, use the “psudo ether driver” devn-fd.so,
by start your io-net like:

io-net -d fd fd=/dev/ser1,ahdlc -p qnet

You can then “ls /net/remote~exclusive:en0”. However, with the lantency on serial link, you will need to tweak a lot of timer (see “use /lib/dll/npm-qnet.so”) and won’t be satisfy with the performance.

For shared memory, the answer is No.

3

Thanks for the help.
Still i have one doubt. now i have established link between 2 computers using qnet. my computer is node-1(my computer) and other is node-2.
Is it not possible to do a Msgsend() to node-2 and specifying that the message transmission has to be thru serial(ser-1) ??
Or do a Msgsend() to node-2 and specify that the message transmission has to be using QoS policy of redundant thru ser1, ser2???

is this doubt valid and please help me to solve this??

4

I am a little confusing here.

So you have node-1 and node-2, and you already established link between them? Can you “ls /net/node-2/” from node-1? What/How do you establish the link? Through Ethernet or through /dev/serX ?

In general, yes, you can use QoS to restrict traffic on one interface, these restriction are per connection based (per “open” based), not per MsgSend() based. When you open a file, you
open it with QoS, something like:

fd = open("/net/node-2/dev/zero~exclusive:en0", O_RDWR);

After that, any read/write to the fd, will restrict traffic exclusively on en0.

5

Hi,
thanks for the reply. i think u may have almost solved the problem.
yes , i have established network using ethernet. i can “ls /net/node-2/”
now i have 1 ethernet and 2 serial ports,
Now what i want to do is ,i want to use ethernet for some other work. i want to use my 2 serial ports to pass messages(some information) to the other node-2 , such that if my one serial port fails , the mesage will be automatically sent through the other serial port.
is there a QoS policy(i think redundant is there) for this or is there any other method. if there is some soution please mention the solution like u mentioned in the last reply:fd = open("/net/node-2/dev/zero~exclusive:en0", O_RDWR);

so basically i want to implement redundancy using serial ports, now that i have established the network.
waiting for ur reply???

6

one more thing, even if there is “redundant” QoS policy for this please mention how to use it ??