Appendix K. Quality Of Service (Qos; Overview; Qos Characteristics; Traffic Filtering - Comtech EF Data CDM-760 Installation And Operation Manual

K.1

Overview

Quality of Service (QoS) is available when the CDM-760 Advanced High-Speed Trunking Modem
is equipped with the optional High-Speed Packet Processor. Use of WAN QoS is typically
required either to filter traffic or perform traffic shaping. WAN QoS should be considered if your
traffic or satellite link meets either criteria and the traffic is packet-based.
K.2

QoS Characteristics

K.2.1

Traffic Filtering

Traffic Filtering prevents certain types of traffic from traversing the network. The need for
Traffic Filtering exists to:
• Block a certain type of service (VOIP, Video, Non-IP, Port Number, etc.).
•
Block a subnet or range of subnets.
•
Block VLANs or a VLAN range.
• Block certain traffic with MPLS-EXP (Multi-Protocol Label Switching Experimental) bits.
K.2.2

Traffic Shaping

Traffic Shaping ensures that high-priority/high-value traffic is more protected than
low-priority/low-value traffic. The need for Traffic Shaping exists when:
•
The traffic on the LAN to be sent over satellite exceeds the WAN capacity.
•
A non-static WAN capacity such as Adaptive Coding and Modulation (ACM) is used, where
user throughput varies.
•
A non-static WAN capacity such as dynamic Single Carrier Per Channel (dSCPC) is used,
where circuits are being set-up, torn down and re-sized.
It is important to note that traffic shaping takes effect on the traffic moving from the LAN to the
WAN. Traffic shaping does not impact WAN-to-LAN traffic.
Appendix K. QUALITY
K–1
SERVICE (Q
OF
S)
O