SD-WAN Customer Administration Guide

On the LAN side, SD-WAN routers support several connectivity options for connecting users, devices, and local networks

The following LAN connectivity types are supported:

Ethernet

LAN subnets can be deployed on gigabitethernet (1 Gbps) or tengige (10 Gbps) interfaces.

In the simplest topology, user devices are connected directly to an Ethernet interface on the SD-WAN router.

However, the most common deployment model is to connect an Ethernet switch between the SD-WAN router and the user devices. This allows multiple devices to access the same subnet and simplifies network expansion.

The following design illustrates common Ethernet deployment topologies.

VLAN (virtual LAN)

VLAN technology allows multiple LAN subnets to share the same Ethernet interface while remaining logically isolated from each other.

In this deployment model, the SD-WAN router is typically connected to an external Ethernet switch through an IEEE 802.1Q trunk link.

Each VLAN is identified by a VLAN tag. The SD-WAN router adds the appropriate VLAN tag to outgoing traffic and processes only the traffic associated with the configured VLANs.

The Ethernet switch uses these VLAN tags to forward traffic to the appropriate access ports, allowing multiple isolated LAN segments to coexist on the same physical infrastructure.

This approach is commonly used to separate different categories of users or devices, such as corporate users, guest networks, servers, or voice services.

The following design illustrates a VLAN-based LAN topology.

Switch

By default, Ethernet interfaces on the SD-WAN router operate as routed interfaces, meaning that each interface belongs to a separate Layer 3 network.

Alternatively, multiple Ethernet interfaces can be grouped together to form a switching domain, also known as a bridge group. In this mode, the router behaves like an Ethernet switch and forwards Ethernet frames between the interfaces that belong to the same bridge group.

This deployment model is useful when multiple ports must provide access to the same LAN subnet.

To forward traffic efficiently, the switching function maintains a table of MAC addresses associated with each port. When an Ethernet frame is received, the router uses the destination MAC address to determine the port on which the destination device is located and forwards the frame accordingly.

When physical interfaces are grouped into a bridge group, the router creates a Bridge Virtual Interface (BVI). The BVI acts as the Layer 3 gateway for the bridged network and hosts the IP address associated with the LAN subnet.

The following design illustrates an Ethernet switch topology.

Wireless LAN

On SD-WAN routers equipped with a Wireless LAN controller, IEEE 802.11 Wi-Fi connectivity is available, allowing the router to operate as a Wireless LAN Access Point (WLAN AP).

The wireless controller supports up to four Wi-Fi networks, represented in the Customer Portal by the interfaces wifi1, wifi2, wifi3 and wifi4.

Each Wi-Fi interface corresponds to a wireless network identified by a Service Set Identifier (SSID), which is broadcast to wireless clients by the router's radio network.

In the most common deployment model, each Wi-Fi interface is associated with its own LAN subnet and hosts the IP address used as the default gateway for wireless devices. In this configuration, wireless and Ethernet networks operate as separate LAN segments and communicate through IP routing.

In some deployments, wireless and Ethernet devices must belong to the same LAN subnet. To support this requirement, Wi-Fi and Ethernet interfaces can be added to the same bridge group.

In this configuration, Ethernet frames are bridged between wired and wireless interfaces, allowing devices to communicate at Layer 2 as if they were connected to the same switch. A Bridge Virtual Interface (BVI) is used to host the IP address associated with the shared LAN subnet.

The following design illustrates common Wi-Fi deployment topologies.