Tos Switch Detection - Comtech EF Data Vipersat CDM-570 User Manual

V i p e r s a t C o nf i g u r a t i o n
Entering I at the command prompt toggles the Video Switch Detection
command for the CDM-570/570L between Enabled and Disabled. When
enabled, a video data-stream will be detected, causing the CDM-570/570L to
send a switch request to the VMS to switch from STDMA to SCPC mode.

ToS Switch Detection

This menu item appears for Remote modems only.
One of the four automatic switching functions that the Vipersat CDM-570/570L
is able to perform is ToS (Type of Service) Switching. 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-SAT (Remote to Hub) direction. Once the ToS Switch
Detection feature is enabled, the Remote modem will send an ASR to the VMS
when a packet stamped with the ToS is detected. The ASR contains the destina-
tion 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.
Entering T at the command prompt in figure 3-35 toggles the TOS Switch
Detection command for the CDM-570/570L between Enabled and Disabled.
When enabling ToS switching, the ToS switching control parameters must be
defined as described in the section "ToS Switching Parameters" on page 3-38.
Applying a ToS value to an application (VoIP, IPVC, or priority data) through
either preservation or classification packet stamping allows the Vipersat switch-
ing system to function in an encrypted network. Normally in a non-encrypted
Vipersat network, packets are classified by the Remote CDM-570/570L using
protocol classification detection and the results are forwarded to VMS via
VESP (Vipersat External Switching Protocol) or, in legacy VMS systems, via
an ASR (Automatic Switch Request) message. The VMS switch detector
service then applies the required or requested bandwidth using policies which
have been pre-configured in the VMS. Refer to the VMS User's Guide for
details.
For example, if in a non-encrypted network a voice application service connec-
tion is started, the CDM-570/570L's classifier analyzes signaling and data
protocols (H.323, SIP, & Data RTP) being routed through the CDM-570/570L.
After connection detection, the process waits for data (RTP). Data is normally
sent after the receiving party answers, which then triggers the system to process
an ASR. Using the ToS classification, the detection function allows application-
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