CalAmp Viper 100 User Manual page 77

― Status Frequency (Available on VPN servers only). The delay (in seconds) between server-status advertisements sent to
VPN clients. An advertisement consists of a few packets sent at an interval determined by the Network Latency setting.
A server's status includes its VPN service state (enabled/disabled) and load (0-100% tunnel capacity in use). A non-zero
value permits VPN clients to 'discover' servers (e.g. they do not need to be pre-configured with server IP addresses).
Clients that are aware of more than one server can select one based on its advertised load.
Note: Regardless of the Status Frequency setting, a VPN server always sends a status to its clients upon its VPN service
changing state (becoming enabled or disabled).
Note: To minimize RF traffic, Server-status packets are broadcast over radio link; devices acting as radio-relays must
therefore explicitly enable station relay mode to forward VPN server-status packets.
Default: 10 seconds
Minimum: 5 seconds (0 = disabled)
Maximum: 60 seconds
― Idle Timeout. Default = 15 minutes. Enter 0 to disable. Enter a value to represent the number of minutes the device
can go with no traffic on the tunnel before it will attempt the Idle Probe and/or Key Exchange. This value affects the
time it takes for VPN clients to re-establish their tunnels after a VPN server (access point) is restarted.
― Idle Probes. Default = 3. Enter 0 to disable. Enter a value to configure the number of Idle Probes to attempt without
receiving a reply back after the Idle Timeout. An Idle Probe attempt consists of a 100 byte UDP packet that is sent or
received via a VPN tunnel. If reply is received, no action is taken. If no reply is received after the specified number of
attempts, the Key Exchange is started immediately. The retry frequency of each probe attempt is affected by the
Network Latency setting. For a Network Latency of 10, the probe frequency is 10 seconds. Idle Probes will not be sent if
the Idle Timeout is set to 0.
― Key Timeout. Enter a value to represent the maximum duration of VPN tunnel security keys (in hours). Default = 6. For
security reasons, the VPN protocol requires all endpoints on the VPN network to re-key periodically. Key Exchange
consists of approximately 12 (80-100) byte long TCP packets (~1 kilobyte), which may take several seconds or more
when retries required. The retry frequency of each key exchange attempt is affected by the Network Latency setting.
For a Network Latency of 10, the key exchange attempt frequency is 10-80 seconds.
― Network Latency. Default =10. This parameter is a multiplier factor for tuning VPN management operations, and
affects the frequency of Idle Probes and Key Exchange attempts. Only change this value by small increments (1-5).
Values should be larger if key exchanges do not complete (refer to the Status and Statistics Section 4.5.3.3). Refer to
the Idle Probe and Key Timeout for the impact of Network Latency.
4.5.3.6 CLIENT SETTINGS
When the operating mode is set to 'Client', the 'Server Settings' part of Figure 56 above is replaced with:
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