The AnywhereUSB/14 offers two redundancy features: IP Network Failover and Redundant Power Supplies. This article contains detailed descriptions of these features.
1. IP Network Failover
To configure IP Network Failover on an AnywhereUSB/14, two network cables should be connected to the two network interfaces "LAN1" and "LAN2" on the back of the unit. LAN1 is considered the primary network interface, and LAN2 is considered the secondary.
Those two cables should ideally be connected to two different Ethernet switches - LAN1/primary to what we''ll call the primary switch, and LAN2/secondary to what we''ll call the secondary switch. In this scenario, if the primary switch fails (either the port that the AnywhereUSB/14 IS connected to, or the switch as a whole), the secondary switch would take over.
Otherwise, those two cables should be connected to two different ports of the same switch - LAN1/primary to what we''ll call the primary port, and LAN2/secondary to what we''ll call the secondary port. In this scenario, if the primary port of the switch fails, the secondary port of the switch would take over.
By default, an AnywhereUSB/14 is configured with IP Network Failover enabled. To confirm this, log into the Web UI of the AnywhereUSB/14, click the "Network" link on the left, then click the "IP Network Failover settings" link in the middle. "Enable IP Network Failover" should be checked. Just underneath that, "Enable IP Network Failover for the Ethernet Interface" should also be checked.
The default "No Test" option means that failover will occur based on the physical "Up or Down" connection status of LAN1/primary. Up means there''s a link to the switch and Down means there''s no link to the switch. As long as LAN1/primary is Up, failover will not occur. If LAN1/primary is Down, failover will occur, where LAN2/secondary would take over. Scenarios where LAN1/primary may be Down are such events as the attached network cable becoming unplugged or cut, or the attached switch or switch port failing.
The other "Ping Test" and "TCP Connection Test" options are advanced methods for the AnywhereUSB/14 to determine if LAN1/primary has a working network connection.
"Ping Test" configures the AnywhereUSB/14 to ping the IP address of a specified network-attached device, i.e. a server (some stable device). If ping replies are not received by the AnywhereUSB/14, failover may occur, depending on the settings related to this option.
"TCP Connection Test" configures the AnywhereUSB/14 to open a TCP connection to an application, i.e. a web server (the default port is 80). If a connection is not successful, failover may occur, depending on the settings related to this option.
Ping Test and TCP Connection Test should generally be used on an "as needed" basis. As an example, let''s say that we test failover using the default No Test option, and the AnywhereUSB/14 takes longer than it should to re-connect to the host PC, due to the switch not yet being aware that the AnywhereUSB/14 is connected to a different port. A longer than usual re-connection time might cause an issue on the host PC related to software that interfaces with the attached USB devices. In this hypothetical scenario, it may be worth trying the Ping Test or TCP Connection Test options, in an effort to decrease the re-connect time. There''s no right or wrong option to use. It depends on the attached USB devices, their related software, and how sensitive they are to the re-connect time of the AnywhereUSB/14. Also note that the Ping Test and TCP Connection Test of add more traffic to the network than the No Test option.
When Failover occurs, the link LED of LAN2/secondary should turn on, and the link LED of LAN1/primary should turn off, both immediately. Also, the AnywhereUSB/14 should remain connected to the host PC.
For more information on configuring IP Network Failover, and a description of the related settings, click the Help link at the top-right, in the AnywhereUSB/14 Web UI.
2. Redundant Power Supplies
The AnywhereUSB/14 has 2 power supplies. If a single power cord / power source is connected to either of the "A/C IN" ports, the unit will power on and function, but without any redundancy. If two power cords / power sources are connected to both of the "A/C IN" ports, the unit will have redundancy - protection from either one of the power supplies going bad, or from one of the power sources (i.e. the battery backup or wall outlet) going bad.