Comtech EF Data CDM-760 - Example 3

Appendix K Revision 4
CDM-760 Advanced High-Speed Trunking Modem MN-CDM760
K–10
K.4.2.3.3 Example 3
• Select Min/Max as the QoS Mode.
• Configure each queue with minimum bandwidth and cost as shown in Table K-8.
• The total available bandwidth is 5000 kbps.
Calculate each individual allocated kbps.
Table K-8. Example 3 – QoS Classification
Queue
Min BW (kbps)
Weight
Allowed BW
Q1 2000 9 – –
Q2 4000 8 – –
Q3
6000
7
– –
Q4
8000 6 – –
Total ► 20000 30 5000
Table K-9. Example 3 Solution – Calculated BW Allocation
Queue
1
st
Round
2
nd
round
N
th
round
Final
kbps
Weight
Given
Leftover
Weight
Given
Leftover
Weight
Given
Leftover
Q1
9
1500
– –
– –
– –
– –
– –
– –
– –
1500
Q2
8
1334
– –
– –
– –
– –
– –
– –
– –
1334
Q3
7
1166
– –
– –
– –
– –
– –
1166
Q4
6
1000
– –
– –
– –
– –
– –
1000
Total ►
30
5000
0
0
0
0
0
5000
Table K-9 displays the solution for Example 3.
Step 1 – Calculate each bandwidth share, based on total weights (30) and available bandwidth
(5000 kbps):
• Q1 = 5000 * (9/30) = 1500 kbps
• Q2 = 5000 * (8/30) = 1334 kbps
• Q3 = 5000 * (7/30) = 1166 kbps
• Q4 = 5000 * (6/30) = 1000 kbps
Step 2 – After the first round, there is no more leftover bandwidth and the calculation loop
stops here.
Step 3 – Each queue’s share after all rounds:
• Q1 = 1500 kbps
• Q2 = 1334 kbps
• Q3 = 1166 kbps
• Q4 = 1000 kbps