Comtech EF Data CDM-625 - Manual (Page 440)

CDM-625 Advanced Satellite Modem Revision 15
Quality of Service (QoS) MN-CDM625
20–8
• Since the modem Tx bandwidth and QoS output data rates are the same, there is no need
for normalization.
• The data rate for each port is as follows:
VLAN
Priority
L2 QoS
Priority
Input Data Rate QoS Output Data
Rate
Remaining Data Rate (After
Serving the Priority Queue)
Output Data
Rate
7 4 500 Kbps 500 Kbps 500 Kbps 500 Kbps
5 3 500 Kbps 500 Kbps 0 Kbps 500 Kbps
3 2 500 Kbps 0 Kbps 0 Kbps 0 Kbps
1 1 500 Kbps 0 Kbps 0 Kbps 0 Kbps
Total ► 2 Mbps 2 Mbps 0 Kbps 1 Mbps
QoS Example 5
1. Port- and VLAN-based Layer 2 QoS mode is selected.
2. Port Layer 2 QoS Priorities are set as follows:
• Port 1 priority is set to 1;
• Port 3 priority is set to 3;
• Ports 2 and 4 priorities are set to trunk mode (native disabled).
3. The modem data rate is set to 4000 Kbps.
4. The ingress traffic on Port 1 is set to 2 Mbps.
5. The ingress traffic on Port 3 is set to 1600 Kbps.
6. The ingress traffic on Port 2 is set to 2000 Kbps with a VLAN Priority of 1.
7. The ingress traffic on Port 4 is set to 800 Kbps with a VLAN Priority of 7.
QUESTION: What is the total output data rate and what are the individual port output data
rates?
ANSWER “A” – For HW Ver. Rev 2.1 and newer:
• Based on Table 20-1 for a modem Tx bandwidth of 4 Mbps, the QoS output bandwidth is set
to 4 Mbps.
• Since the modem Tx bandwidth and QoS output data rates are the same, there is no need
for normalization.
• Based on Table 20-2, the VLAN Priorities 7 and 1 are mapped, respectively, to L2 QoS
Priorities 4 and 1.