User guide

VMS Network Configuration
3-38 VMS User Guide
switch a terminal to its CIR. Requests for rates above the CIR are granted on a
first-come, first-serve, best effort basis. A terminal that does not have an
assigned CIR has no guarantee for any bandwidth, and is only granted band-
width on a purely opportunistic basis.
The Basic Guaranteed Bandwidth / CIR function depends on the pre-allocation
of system resources, namely RF spectrum and network hardware devices
(demodulators). Overlaying frequency masks are utilized for the pre-allocation
of bandwidth, as illustrated in figure 3-47.
Figure 3-47 Visualization of Basic Guaranteed Bandwidth
Mask 1 designates the frequency spectrum that is reserved for sites with defined
CIR bandwidth slots. The slot size is equal to the Minimum Bit Rate value that
is defined by the site Policy parameter setting.
Mask 2 designates a separate spectrum allocation dedicated to sites that are
selected to operate within this priority frequency segment. Creating this spec-
trum mask is optional when setting up the Basic Guaranteed Bandwidth feature.
CIR Configuration
The configuration of CIR involves four steps:
• Enabling CIR on the Satellite
• Setting the CIR policies — first the Global, then the Local Subnet
• Enabling CIR on the Remote Antenna(s)
• Defining the Priority Bandwidth allocation (optional)