Comtech EF Data SLM-5650A Vipersat Parameter Editor - Manual (Page 36)

Vipersat
2-20 SLM-5650A Parameter Editor User Guide
Typically the default value will be sufficient. Note that this value must be less
than the value specified for the SCPC Step Up Threshold.
Step Delay
This field appears for the Remote modem only.
The Step Delay feature provides a switching delay period to ensure that a
premature switch up or down in the SCPC rate does not occur due to a tempo-
rary rise or fall in traffic.
Excess Capacity
This field appears for the Remote modem only.
During each SCPC Step Up switch, the excess capacity data rate value entered
by this command is added to the new SCPC data rate. This excess is added each
time an SCPC Step Up switch occurs. This setting makes additional bandwidth
available for when the demand arises while minimizing Step Up switching
events.
ToS (Type of Service)
This menu item appears under Switching when the Unit Role is Remote, and is
used to define and make modifications to the ToS switching rules.
Type of Service (ToS) is defined by an eight bit field within an IP packet header
that is used to set up per-hop-based QoS rules for prioritizing packets. Because
the ToS field remains untouched by most encryption methods, ToS switching
provides an alternative means of SCPC switching when encryption prevents the
detection of SIP and H.323 protocols.
ToS detection occurs in the Remote modem which only looks at traffic that is
passed in the LAN-to-WAN (Remote to Hub) direction. Once the ToS Switch
Detection feature is enabled, the Remote modem will send a switch request to
the VMS when a packet stamped with the ToS is detected. The request contains
the destination IP address of the ToS stamped packet, the desired SCPC rate,
and the VMS Switch Type (policy #). If available hardware and bandwidth
exist, the VMS will establish the SCPC carrier automatically.
ToS switch detection is controlled by the Remote, and thus appears only in the
Automatic Switching: Remote dialog where it is Enabled via a check box
(figure 2-12).
ToS switch rules are configured by clicking on the TOS menu item that appears
for Remote modems, as shown in figure 2-13.