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 classifier 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 destination 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 3-34toggles 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 3-32.
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- based switching in encrypted networks where the signaling protocols are encrypted or effectively hidden.
Note: Load switching by the VMS is not affected by enabling ToS detec- tion.