User's Manual

EnRoute500 User’s Guide
TR0149 Rev. C5
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It is recommended that an IP address, rather than a hostname, is specified for the
‘monitor.health.host’ parameter to avoid a DNS failure from causing the gateway to
believe that its backhaul link is down. The IP address of the closest backhaul router
would be an appropriate host to specify.
15.3 Layer 2 Emulation
Certain back-end systems (Internet gateways) use the MAC addresses of client devices for
authentication and accounting purposes. The EnRoute500 uses a layer 3 approach to mesh
routing, which means that the client MAC addresses are typically not provided to the back-end
servers. A layer 2 emulation mode can be enabled on the EnRoute500 to provide the client
MAC address information to back-end systems.
When the layer 2 emulation mode is enabled, a mesh cluster gateway will send Ethernet (layer
2) frames to the WAN using the MAC address of the device the packet originated from as the
source address. Mesh gateways will also act as proxies and forward packets with MAC
destination addresses of clients that are in the mesh cluster they service.
Layer 2 emulation is enabled with the ‘l2_client_mac_fwd’ parameter in the ‘sys’ interface. This
parameter should be set to the same value for all devices in a given mesh cluster. The
example below shows how to enable layer 2 emulation.
> use sys
sys> set l2_client_mac_fwd=yes
In combination with a centralized DHCP server, layer 2 emulation allows the EnRoute500
mesh network to behave like a series of access point bridges, a mode which is required by
certain Internet gateways to successfully forward IP packets to clients. For more information on
setting up a centralized DHCP server, see section 10.2.