Comtech EF Data Vipersat CDM-570 Podręcznik Użytkownika Pobierz pdf (Strona 139)

Appendix B - Automatic Switching B-21

ToS Switching

Figure B-10

Per Type ToS Switching Example

ToS Remarking

For situations where the application device is not capable of stamping a packet

with a ToS value, or where the application traffic is generated by a variety of

different hosts and protocols, ToS remarking should be considered. ToS

remarking refers to a device, such as a router, that has the capability of re-

stamping packets with a user defined ToS value. Devices that support remarking

often allow users to assign a ToS value to packets that match certain source or

destination IP addresses, port numbers, and/or protocols.

Example 1: A user wants to switch up whenever a host performs an FTP across

the satellite. A device that supports remarking can be placed between the appli-

cations and the remote modem. The device can then be configured to stamp all

traffic that utilized FTP port 21 with a particular ToS value. The remote modem

can then be configured to detect this value and switch to a specific SCPC bit

rate.

Example 2: A remote customer is using an IP based video encoder to transmit

video over the satellite. The encoder does not have the option to assign a ToS

value for prioritization. Again, a remarking device can be placed between the

encoder and the remote modem and configured to assign a ToS value to all

packets received from the encoder.

Figure B-11 provides an example of a router performing ToS remarking for

VoIP phones.

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Comtech EF Data Vipersat CDM-570 Podręcznik Użytkownika Strona 139