Lucent Technologies PacketStar PSAX 4500, Руководство пользователя

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Chapter 3 System Features
Multiservice Media Gateway Software Features
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PacketStar
®
PSAX 4500 Multiservice Media Gateway User Guide , Issue 2 Release 8.0.0
1. In box 1, the first queue is 386 with a T value = 20. The ATM traffic
shaper reads these values.
2. The ATM traffic shaper sends out a cell from queue 386, and calculates
the new location for queue 386:
T value = 20 + box # 1 = (20+1) = 21
3. The ATM traffic shaper transfers queue 386 into box 21 on the ATM Traf-
fic Shaping table (to the bottom of the queue stack in box 21 if that box
has other queues in it. If the box is empty, queue 386 is now first in line
to transmit a cell when the ATM traffic shaper gets to box 21).
4. The ATM traffic shaper progresses to box 2 on the ATM Traffic Shaping
table, and repeats the process described in Steps 1 and 2 above.
5. On box 2 of the ATM Traffic Shaping table, the first queue is 1999 with a
T value = 35. The ATM traffic shaper reads these values.
6. The ATM traffic shaper sends out a cell from queue 1999, and calculates
the new location for queue 1999:
T value 35 + Box # 2 = (35+2) = 37
7. The ATM traffic shaper transfers queue 1999 into box 37 on the ATM
Traffic Shaping table to the bottom of the queue stack in box 37.
8. The ATM traffic shaper progresses to box 3 on the ATM Traffic Shaping
table, and repeats the process described in Step 1 and 2 above.
9. On box 3 of the ATM Traffic Shaping table, the first queue is 6 with a T
value of 50. The ATM traffic shaper reads these values.
10. The ATM traffic shaper sends out a cell from queue 6 and calculates the
new location for queue 6:
T value 50 + Box # 3 = (50+3) = 53
11. The ATM traffic shaper transfers queue 6 into box 53 on the ATM Traffic
Shaping table to the bottom of the queue stack in box 53.
12. The ATM traffic shaper progresses to box 4 of the ATM Traffic Shaping
table and repeats Steps 1 through 3 and cycles through all 80,000 cells
over and over, using this algorithm.
Traffic-shaped queues have the priority of "VBR-shaping" which is below
VBR-rt2 and above VBR-nrt1. Generally, in an AQueMan environment, traf-
fic from all CBR queues and VBR-rt queues will be sent before the traffic
shaped queues are examined. The existence of CBR and VBR-rt traffic on the
ATM module will cause the module to send traffic shaped cells below the tar-
geted PCR.
Formula for
Determining the PCR
of an ATM Traffic-
Shaped Connection
For ATM traffic-shaped connections, you should set the PCR value so that it
conforms to the following expression:
where:
PCR >
SCR
(1 - F )