> For the complete documentation index, see [llms.txt](https://prosbcdocs.telcobridges.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://prosbcdocs.telcobridges.com/telecom-references/sip-and-voip/voip-bonding.md).

# VoIP Bonding

VoIP Bonding refers to the capability of Tmedia units to use the two available VoIP Ethernet ports as a bonding pair. When the active port becomes unusable (cable disconnected, limited connectivity), the other port is used to transport Ethernet traffic.

Detection of offline ports is currently achieved through two methods:

1. Ethernet PHY polling to quickly discover if a cable is connected or not to the unit;
2. Sending IPv4 ping requests to a known host to ensure that a logical IP path is available to the unit.

The voip0 (first VoIP port) MAC and IP addresses are used on both VoIP ports of the Tmedia unit when VoIP bonding is activated. However, in that mode, the voip1 port MAC and IP address are not usable (i.e. protocol stacks assigned to voip1 will not work and voip1 will not respond to ICMP requests). Therefore, IP services and stacks (such as SIP, SIGTRAN and port ranges) must be assign to voip0 only.

The VoIP Bonding feature also makes the Tmedia units report the bonding state as the voip0 port state. For instance, the IPv4 statistics reported by the Web Portal for voip0 are actually for the bonding pair. The PHY state is also for the bonding pair (so it would only be down if both voip ports are down). To know the true state of the physical voip0 and voip1 ports, the SNMP protocol must be used.

The feature has no effect on Virtual IP Interfaces configured in the Web Portal. Virtual IP Interfaces configured on either voip0 or voip1 physical ports still work exactly the same whether VoIP Bonding is activated.

### Web Portal Display

**VoIP0 Port Status**

Since VoIP0 and VoIP1 are bonded together, VoIP0 represents an aggregated status of the bonded ports. This means VoIP0 will be shown as "RED" only if both VoIP0 and VoIP1 ports are unavailable.

**VoIP1 Port Status**

VoIP1 port status represents its own physical connectivity.

**Web Portal Ports Display Status**

|                       | Physical Connectivity  | Physical Connectivity  | Physical Connectivity  | Physical Connectivity  |
| --------------------- | ---------------------- | ---------------------- | ---------------------- | ---------------------- |
| VoIP0 Interface       | UP                     | UP                     | DOWN                   | DOWN                   |
| VoIP1 Interface       | UP                     | DOWN                   | UP                     | DOWN                   |
|                       | Web Portal Port Status | Web Portal Port Status | Web Portal Port Status | Web Portal Port Status |
| VoIP0 (Bonded Status) | GREEN                  | GREEN                  | GREEN                  | RED                    |
| VoIP1                 | GREEN                  | RED                    | GREEN                  | RED                    |

### Configuration

* [VoIP Bonding](https://github.com/telcobridges-main/tmedia-wiki/tree/main/tmedia/configuration/configuring-a-virtual-port/README.md)


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