[arm-allstar] Hub or no hub, that is the question

[Jeremy georges]

 Thanks Chris.
I was hoping to get a better understanding of the packet flow and loop prevention - especially when not using a 'hub'.

I just did a tcpdump on 3 nodes...and it appears that whatever order you connect the nodes, that is the UDP packet flow on port 4569. If a node is already connected (even if its one of the other 2 of the 3 nodes) it will say already connected("remote already in this mode")...even though I do not see any UDP traffic between node 3 and node 1.
Example:Node 3 is the main site. I connect node 1 to 3 and node 2 to 3.When transmitting, I only see bi-directional traffic (UDP port 4569) between node 1 and 3 and node 2 and 3. There is no direct communication between node 1 and 2. It appears that node 3 is doing all of the processing of packets.
If I try to connect node 1 & 2, I get the message "Remote already in this mode".

So this leads me to a couple of questions:
1. How are we preventing loops? So in the above example, I did not manually connect node 1 & 2, (just 1 to 3 and 2 to 3) but it already knew that these nodes all have an active path to each other. It's using node 3 to get to the other node. Is the node ID connected list broadcasted to all of these that are connected? And its just using the Node ID to prevent a loop?
2. I don't see any authentication. It appears that we'll just accept anything on port 4569. Is there any way to add some sort of authentication? Even if its just a simple md5 key?

If there is a doc somewhere I should be reading on this, please let me know. It seems like info is around...just scattered. Maybe its just my Google-fu is not good enough :-)
Thanks,
-J
    On Sunday, January 10, 2021, 4:45:07 PM PST, Chris Andrist <chris.andrist at outlook.com> wrote:  
 
 Hi Jeremy,

app_rpt will allow each node to be a node, hub, or node and hub.

Personally I like to use hubs. This make the system more redundant to me.

However, that is the beauty of app_rpt. Do what works best for you and your group.

—
Regards,

Chris Andrist, KC7WSU

> On Jan 10, 2021, at 5:40 PM, Jeremy georges via ARM-allstar <arm-allstar at hamvoip.org> wrote:
> 
> Folks,
> For 3 private nodes, do you need a dedicated hub? Or can you just define them on one of the centralized nodes and make it a 'hybrid'  node. In other words, just define all the other nodes in the rpt.conf file on the main site and then the other sites just have the main hub site listed in their respective rpt.conf?
> Or do I have to have a dedicated hub for more than 2 concurrent nodes attached?
> I did not see any clear documentation on this; if there is some notes somewhere, please share that.
> Thanks!
> -J
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