ArcLight Hub User’s Guide
General System Description
1-22 1081006 Rev. 001
1.4.3.2.5 Return Channel Chipping Rate
Return Channel chipping rate is selectable within an information rate
dependent range.
It is expected, but not required, that all Return Channels in a given
network will be operated with the same chipping rate.
1.4.3.3 Data Link Layer Requirements
1.4.3.3.1 Packetization
Return Channel data are packetized into standard 53 octet
Asynchronous Transfer Mode (ATM) cells prior to being burst over the
channel.
IP data are encapsulated by the VMT into ATM cells using the
techniques of ATM Adaption Layer 5 (AAL5).
Permissible Return Channel burst sizes are 1, 2, or 4 ATM cells.
The burst size(s) that a particular VMT may employ is a configurable
parameter, settable either locally or remotely via the NMS.
1.4.3.4 Robust Return Channel
Each ArcLights network includes at least one correlator operating at a
date rate that is sufficiently low for the least advantaged network VMT
to successfully close a satellite link to the Hub at that rate.
This Robust Return Channel rate is used by all VMTs to transmit its
login message to the NMS. The VMT continues to use this Robust
Return Channel rate until instructed to use an alternate rate by the
NMS.
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