What Causes "Communication Error" and How To Fix It

You may have seen the error above at different times, and it may even have interrupted your stream or prevented you from successfully starting a stream.  This article will take a look at what the error means, some common causes of it, and what to try and do to overcome it.

What Communication Error Means and What Causes It

All LiveU Solo units talk to the LiveU backend via a command and control protocol.  Note, they talk to the LiveU backend, and not directly to the regional servers used for the LRT elastic cloud.  Meaning, your unit talks to the LiveU C&C backend and never communicates directly with a server in Sydney, when you are using AU_Sydney as your zone (never communicates directly, for C&C, video and audio are sent directly from the unit to the regional server, but only as packets of video and audio).

Communication Error means that C&C communication was interrupted in a way that the unit was not able to recover it.  Specifically, since the units use many connections at once (and are built for resiliency), there is a technique used for the C&C communication that relies on more than one of the connections at once and can rapidly switch to other connections if needed.  The LiveU C&C backend is also made up of a cluster of services for redundancy and can make changes based on events like unexpected downtime.  All of this means that in normal and even challenging scenarios, C&C packets should be making it back and forth from the unit to the cloud even as things change - if a modem loses its connection, if a WIFi network disconnects, etc.

However, if a scenario happens that can't be overcome by these resiliency steps, you will get Communication Error.  

What scenarios could lead to this, all the redundancy steps failing and seeing the error? Here are some examples but others are possible as well:

• All of your connections fail: for instance, you are using two modems and you move to an area that has so little cellular coverage, neither modem can provide enough bandwidth to get C&C communication out
• You are only using one connection (perhaps in RTMP Direct mode) and that single connection fails even temporarily
• You are behind a connection that has very restrictive traffic control or a restrictive firewall and it does not allow the C&C packets out
• You have multiple connections, but due to an IP routing conflict the C&C packets are not being routed correctly (this seems to be actually the most common scenario)

Of course, other scenarios, even if less common, could cause this as well:

• The LiveU C&C Backend is entirely down or not responding (thankfully, our uptime on this component is five-nines!)
• C&C packets are being routed however the response causes a crash on the unit (this bug has occurred in some past firmwares, but we have no known open bug for it on latest)

And sometimes it can feel a bit difficult to determine what might be the cause: was this my local connections? Did my modems cause this? or was this LiveU's cloud?  Also, because this single error message is displayed for any scenario where C&C communication is interrupted in a way that the resiliency steps can't recover, it may sometimes feel like it is a more general problem - you may see other users in the user group report the same error, or you may have experienced under specific conditions in the past. However, often times the cause of it is still a specific condition, often local to the connectivity of the unit, and not a more general problem.

As you can see from the scenarios above - the most likely causes are "local" causes -connectivity at the unit either changing, failing, or otherwise behaving badly.

But if ever in doubt, of course contact LiveU support and we can help debug further.

What To Do About Communication Error

Now that you understand the cause of communication error (loss of the C&C communication to the LiveU backend), some potential steps to overcome it will likely make more sense:

1. If you are only using a single connection for streaming, make sure that connection is allowing outbound traffic and is not having trouble such as packet loss or restricted bandwidth
2. Use more than one connection if you can
3. If using two or more connections, be very sure you don't have an IP routing conflict as that can frequently lead to this error
4. If you just recently added a new connection to your toolbox, try a test without that connection - if you just got a new modem for example, and then start seeing this error more frequently, again you may start to suspect some IP routing conflicts or other issues with that new connection
5. If you are using 3 or 4 connections, and are sure you have no IP routing conflict, try eliminating one of the connections that you suspect might be performing poorly

As you can see, all of these steps are focused around "make sure the unit can route C&C to the cloud successfully", as that is the usual cause of this issue.

Conclusions

The Communication Error message is a general message that means the unit did not successfully communicate with the LiveU C&C backend, and is not directly related to the regional LRT servers that provide elastic service.  The most common causes are issues that would block the LiveU Solo unit communicating smoothly with the cloud, such as IP conflict, restrictive firewalls, or connections with very poor performance (high packet loss and low bandwidth).  While the C&C technique on your LiveU Solo has many redundancies built in, when these redundancies can't overcome issues getting to the cloud, you may see Communication Error on our device.