Re: Reliable Message Delivery - JxtaBiDiPipes

On 10-Aug-05, at 2:43 PM, Poole, Paul P1 wrote:

> Hi all:
>
> As my previous posts might suggest, I am very interested in  
> reliable communication with MyJXTA.  In my build of JXTA, I have  
> set JxtaBiDiPipe communication to default to reliable (e.g.  
> isReliable = true).  With this build, I have setup an isolated  
> environment consisting of only 2 nodes (laptops).  As a test of the  
> reliability of these pipes, I did the following:
>
>         1. Fired up MyJxta on laptop (node) 1
>         2. Set node 1 as a rdv
>         3. Fired up MyJxta on laptop (node) 2
>             Note: both nodes see each other fine
>         4. Initiate a "chat with peer" from node 1 (rdv) to node 2
>             Note: a test shows that the one-on-one chat is working  
> correctly for both nodes
>         5. Remove node 2 from the network (I simply unplugged the  
> ethernet cable)
>         6. Send a sequence of messages from nodes 1 and 2
>
> At this point in the test, after a few messages are sent (within 10  
> - 15 seconds), both node's MyJXTA windows stop responding.  It is  
> as if when it detects that the linkage has been broken, a blocking  
> occurs.  Upon reconnection of the ethernet cable (after about 20 -  
> 30 seconds) the two nodes start responding again and can  
> communicate.  Importantly, not all of the messages sent from the  
> two nodes reach their destination… some messages are lost and those  
> that are received are not necessarily in order (this goes for both  
> nodes).
>
> Interestingly, if I perform this exact test with the JxtaBiDiPipe's  
> isReliable set to false, then the two nodes do NOT stop responding  
> AND ALL of the messages are received for both nodes (for these  
> tests, the node was removed from the network for about 45 - 55  
> seconds).  However, the order is not always correct.
>
> Is this an expected result?  If not, can someone reproduce these  
> results?
>
> What I would consider ideal is when a node leaves for a BRIEF  
> period of time, messages will be queued by the senders (by this I  
> mean messages sent by the node that left and the one that stayed)  
> until the node returns.
>
> My next test will be to add a third node, which will be the rdv and  
> can act as a liaison.
>
> Any thoughts?

I believe if you use a relay between the peers, the relay will store  
and forward messages on behalf of briefly disconnected clients.

Vanessa


> Thanks,
>
> Paul Poole
> Software Engineer
> Lockheed Martin
>