If you’re using multiple networks simultaneously, it stands to reason that having more connections would mean more reliability. After all, if one network fails, there are lots of other options, so there’s less of a chance your stream would go offline – right? More modems = more bandwidth = better reliability, right?

No, not necessarily.

The way your networks are managed by your codec is more important than the number of networks you have connected. In fact, we’ve found in our testing that having more modems can often cause interference (which is why our Comrex Connect Modems are RF-optimized).

Say you’re working with a bonded connection that has four cellular networks. Your system is sending a certain amount of data on each one, and it’s working fine. Suddenly, one of the networks becomes patchy, and it’s no longer able to handle its data load.

But your codec doesn’t quickly change the amount of data it’s allocated to the network – it keeps sending more than the network can handle. In this case, even though you’re running four networks at once, you’ll still end up with delays and decreased audio quality, because the data load isn’t being managed efficiently.

This is how we think about bonded IP at Comrex –

If you’re sending audio over cellular connections, we can’t control how fast or slow a connection will be; however, we can control the way that data is distributed across networks.

That’s why we’ve focused on creating and perfecting CrossLock, our VPN technology that includes a suite of reliability tools designed to intelligently and responsively manage network connections in real time

What makes CrossLock different?

CrossLock allows our IP codecs to use multiple IP networks at once. Its adaptive management engine monitors the performance of each network link, and dynamically adjusts data load depending on each network’s performance. 

When used in bonding mode, CrossLock does more than just aggregate the available bandwidth of your networks. It compares each network’s performance to calculate the highest quality and lowest delay combination of networks, even temporarily quarantining any underperforming networks so that they don’t detract from performance. It does all of this seamlessly, so your listeners won’t hear any drops in audio. And it works automatically, so engineers don’t have to adjust settings.

CrossLock features forward error correction, deadline sensitive retransmission, and congestion detection – all tools the adaptive management engine employs when network conditions change. 

CrossLock can also be used in redundancy mode, in which an identical audio stream is simultaneously transmitted over a second network, providing a fail-safe should one network fail completely. 

CrossLock is included with all new Comrex IP audio codecs, and is free to install on older IP audio codecs that can support firmware version 4.0 or higher.


Learn more about CrossLock

Curious about our IP audio codecs?
Contact our sales team.

Not sure if your unit supports CrossLock?
Need assistance with updating firmware?
Contact the techies during business hours.


Click here for this blog post in Spanish.