Virtual Interfaces (VLAN)

On the SonicWALL NSA Series and SonicWALL PRO 2040/3060/4060/4100/5060 security appliances, virtual Interfaces are sub-interfaces assigned to a physical interface. Virtual interfaces allow you to have more than one interface on one physical connection. Virtual interfaces provide many of the same features as physical interfaces, including Zone assignment, DHCP Server, and NAT and Access Rule controls. Selecting Layer 2 Bridged mode is not possible for a VLAN interface.

VLAN support on SonicOS Enhanced is achieved by means of sub-interfaces, which are logical interfaces nested beneath a physical interface. Every unique VLAN ID requires its own sub-interface. For reasons of security and control, SonicOS does not participate in any VLAN trunking protocols, but instead requires that each VLAN that is to be supported be configured and assigned appropriate security characteristics.

Figure 2. VLAN Interfaces

SonicOS Enhanced 4.0 and higher can apply bandwidth management to both egress (outbound) and ingress (inbound) traffic on the WAN interface. Outbound bandwidth management is done using Class Based Queuing. Inbound Bandwidth Management is done by implementing ACK delay algorithm that uses TCP’s intrinsic behavior to control the traffic.

Class Based Queuing (CBQ) provides guaranteed and maximum bandwidth Quality of Service (QoS) for the SonicWALL security appliance. Every packet destined to the WAN interface is queued in the corresponding priority queue. The scheduler then dequeues the packets and transmits it on the link depending on the guaranteed bandwidth for the flow and the available link bandwidth.