Type Of Service (Tos) Switching - Comtech EF Data Vipersat CDM-570 User Manual

T y p e o f S e r v i c e ( T o S ) S w i t c h in g

Type of Service (ToS) Switching

Type of Service (ToS) switching is used on circuits carrying encrypted traffic
where the packets cannot be examined to determine the type of traffic being
carried. 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 Automatic Switch Request (ASR) messages.
The VMS switch detector service then applies the required or requested band-
width using policies which have been pre-configured in the VMS.
For example, in a non-encrypted network if 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, detection function allows application-based-
switching in encrypted networks where the signaling protocols are encrypted or
effectively hidden. ToS adds the type of service to the un-encrypted Quality of
Service byte (QoS) in the header which then can be analyzed to determine the
type of service being transmitted. Once the type of service is determined, VMS
uses this information to perform switching following the policies established for
the detected traffic type.
Note: Load switching by VMS is not affected by enabling ToS detection.
NOTE
Applying a ToS value to an application (VoIP, IPVC, or priority data) through
either preservation or classification packet stamping allows the VMS to func-
tion in an encrypted network.
A p p e n d i x A u t o m a t i c S w i t c hi n g
B - B-13