In addition to the physical interfaces, you can create the following types of logical interfaces on the FortiVoice Gateway:
A Virtual LAN (VLAN) subinterface, also called a VLAN, is a virtual interface on a physical interface. The subinterface allows the forwarding of VLAN tagged packets using that physical interface, but it is separate from any other traffic on the physical interface.
VLANs use ID tags to logically separate devices on a network into smaller broadcast domains. These smaller domains forward packets only to devices that are part of that VLAN domain. This reduces traffic and increases network security.
One example of an application of VLANs is a company’s accounting department. Accounting computers may be located at both main and branch offices. However, accounting computers need to communicate with each other frequently and require increased security. VLANs allow the accounting network traffic to be sent only to accounting computers and to connect accounting computers in different locations as if they were on the same physical subnet.
For information about adding VLAN subinterfaces, see Configuring the network interfaces.
On the FortiVoice Gateway, you can combine two or more physical interfaces to provide link redundancy. This feature allows you to connect to two or more switches to ensure connectivity in the event one physical interface or the equipment on that interface fails.
In a redundant interface, traffic is only going over one interface at any time. This differs from an aggregated interface where traffic is going over all interfaces for increased bandwidth. This difference means redundant interfaces can have more robust configurations with fewer possible points of failure. This is important in a fully-meshed high availability (HA) configuration.
A physical interface is available to be in a redundant interface if the following conditions are met:
- The physical interface is not a VLAN interface.
- The physical interface is not already part of a redundant interface.
- The physical interface has no defined IP address and is not configured for DHCP.
- The physical interface does not have any VLAN subinterfaces.
- The physical interface is not monitored by HA.
When a physical interface is included in a redundant interface, it is not listed on the System > Network > Network page. You cannot configure the interface anymore.
For information about adding redundant interfaces, see Configuring the network interfaces.
A loopback interface is a logical interface that is always up (no physical link dependency) and the attached subnet is always present in the routing table.
The loopback IP address of the FortiVoice Gateway does not depend on one specific external port, and it is therefore possible to access it through several physical or VLAN interfaces. In the current release, you can only add one loopback interface on the FortiVoice Gateway.
For information about adding a loopback interface, see Configuring the network interfaces.