Comtech EF Data CDM-760 - Example 4

Appendix K Revision 4
CDM-760 Advanced High-Speed Trunking Modem MN-CDM760
K–11
K.4.2.3.4 Example 4
• Select Min/Max as the QoS Mode.
• Configure each queue with minimum bandwidth and cost as shown in Table K-10.
• The total available bandwidth is 8000 kbps.
Calculate each individual allocated kbps.
Table K-10. Example 4 – QoS Classification
Queue
Min BW (kbps)
Weight
Allowed BW
Q1 1000 9 – –
Q2 2000 8 – –
Q3
3000
7
– –
Q4 4000 6 – –
Total ► 10000 30 8000
Table K-11. Example 4 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
2400
1400
-
-
-
-
-
-
1000
Q2
8
2134
134
-
-
-
-
-
-
2000
Q3
7
1866
-
7
826
-
-
-
-
2692
Q4
6
1600
-
6
708
-
-
-
-
2308
Total ►
30
8000
1534
13
1534
0
0
0
0
8000
Table K-11 displays the solution for Example 4.
Step 1 – Calculate each bandwidth share, based on the total weights (30) and available
bandwidth (8000 kbps):
• Q1 = 8000 * (9/30) = 2400 kbps
• Q2 = 8000 * (8/30) = 2133 kbps
• Q3 = 8000 * (7/30) = 1866 kbps
• Q4 = 8000 * (6/30) = 1600 kbps
Step 2 – After the first round, only Q3, and Q4 still have unmet max bandwidth queues.
Calculate each bandwidth share, based on the total remaining weights (13) and available
bandwidth (1534 kbps):
• Q3 = 1534 * (7/13) = 826 kbps
• Q1 = 8000 * (6/30) = 708 kbps
Step 3 – After the second round, there is no more leftover bandwidth so the calculation loop
stops here.
Step 4 – Each queue’s share after all rounds:
• Q1 = 1000 kbps
• Q2 = 2000 kbps
• Q3 = 2692 kbps
• Q4 = 2308 kbps