ViaSat ArcLight, User Manual, Page: 302 / 368

ArcLight Hub User’s Guide
Component Operating Procedures
5-50 1081006 Rev. 001
5.11 Forward Link Modulator (VFLM-70)
5.11.1 Overview
The VFLM-70 is a 19-inch rack-mounted unit that runs ViaSat’s FLM
(Forward Link Modulator) software and provides the delivery of
broadband IP data to a collection of VMTs within the ArcLight satellite
network. The VFLM-70 consists of a single unit 19-inch rack-
mountable enclosure and is installed at a ArcLight Hub site. The FLM
interfaces to the network on the hub side over a 10/100 base-T
Ethernet interface and outputs an RF signal at a 70MHz IF. The FLM IF
is connected to a PCMA Hub Canceller and through it to an appropriate
upconverter, e.g. L-Band or Ku-Band.
The majority of IP traffic originating at the ArcLight Hub, or received at
the Hub from its external interfaces, is routed through the FLM to the
VMT network popluation. Other packets terminate at the FLM. The FLM
has a unique IP address held in non-volatile memory for network
addressing. This address is typically on the main ArcLight Hub segment
10.1.1.0/24, e.g. 10.1.1.47/24.
Figure 5-34 illustrates the IP packet flow in the FLM. The FLM supports
the following services for its control and management:
•
ICMP
•
Telnet Server
•
FTP Server
•
SNMP Agent
•
LEDs/Front Panel Indicators
SNMP
TELNET
5.1
FLM
Satellite
Network
User LAN
IP network with
- Multicast
- ICMP
5.2
FTP
ICMP
NOC LAN
- TCP/IP
- UDP
Figure 5-34. FLM Data Flow Diagram.
5.11.1.1 ICMP
The FLM provides an ICMP application so that “Ping” can be used to
test for proper FLM IP connectivity.