About WAN bonding

WANClosed Wide Area Network bonding is a the process of aggregating two or more WAN interfaces so that data packets are simultaneously distributed across all active connections for increased throughput, optimized latency, and seamless failover. The goal is to improve throughput, reliability, and resilience of a network by treating multiple WAN links as one.

  • Multiple links active: The router uses all available WAN interfaces concurrently — such as LTE/5G, wired broadband, or satellite.

  • Traffic splitting: Outgoing traffic is divided into smaller packets and sent across different WAN links.

  • Recombination at server: On the other end, a WAN Bonding server (also called a tunnel endpoint or aggregator) receives and reassembles the packets into the correct sequence before forwarding them to the destination.

  • Dynamic load balancing: The router continuously monitors link performance (latency, packet loss, jitter, bandwidth) and adjusts how traffic is distributed in real time.

  • Failover and redundancy: If one connection fails, the bonded tunnel remains active using the remaining links — ensuring seamless failover with little or no session interruption.

  • Higher throughput: Combines bandwidth from multiple WANs.

  • Improved reliability: Multiple links mean continuous connectivity even if one link drops.

  • Reduced latency & jitter: Traffic can be optimized dynamically for low latency.

  • Session persistence: Maintains ongoing sessions (VPN, video call, etc.) even during link failover.

  • Better utilization: Makes use of all available WAN resources efficiently.

On most Digi EX, IX, and TX cellular routers, WAN Bonding is implemented via Digi’s SD-WAN / WAN Bonding feature in conjunction with Digi Remote Manager. It uses a secure tunnel to a Digi or customer-hosted bonding server that reassembles the split packets, effectively merging:

  • Cellular + Wired broadband, or

  • Multiple Cellular SIMs (e.g., from different carriers)

This results in higher aggregate bandwidth and uninterrupted connectivity for demanding IoT and enterprise applications.

Note All Digi cellular extenders and routers can use the WAN bonding service except for the EX12, IX10, and IX15.