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.
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.
