|
|
This chapter describes how to calculate the resource allocation for MCU services. The topics include:
The Cisco IP/VC 3510 MCU is designed for small- to medium-size videoconference calls. The number of calls the MCU can process at one time depends on the number of participants and the video bit rate allotted for each call. The participants-per-video-bit-rate tables in Chapter 5 show the maximum number of participants for both standard videoconference calls and videoconference calls with continuous presence. (For stacked MCUs, the values apply to each MP.)
The MCU uses admission control to determine whether to process a videoconference call request. The system bases its determination on the resources that are allocated for the calls in progress and the resources that need to be allocated for the requested call. Resources are allocated using the values specified in the service the user dials to initiate the call. If the resources required for the requested call plus the resources the MCU is allocating for current calls are within the processing capacity, the MCU processes the requested call. If these resources exceed the capacity, the MCU rejects the requested call.
For example, if the MCU is managing 115-kbps video bit rate videoconferences for four participants and seven participants, and a request for a third 115-kbps video bit rate videoconference for three participants is received, the MCU will process the call. In this case, the total number of participants at the 115-kbps rate is 14. The MCU can process calls for up to 15 participants at this video bit rate. A request for a fourth 115-kbps video bit rate videoconference for three participants would push the MCU to 17 participants and exceed the processing capacity. The fourth call is rejected.
The MCU uses a weighting system to determine the resources allocated to a service and the resources available for processing. The following algorithms let you calculate how much processing capacity standard and continuous presence services use.
To determine the resource capacity a standard MCU service uses, use the following algorithm:
where:
| Bandwidth Calculation | Call Weight |
|---|---|
If 100 <= 2 * (video BW + audio BW)< 250 | 25 |
If 250 <= 2 * (video BW + audio BW) < 328 | 19 |
If 328 <= 2 * (video BW + audio BW) < 448 | 15 |
If 448 <= 2 * (video BW + audio BW) < 568 | 14 |
If 568 <= 2 * (video BW + audio BW) < 700 | 13 |
If 700 <= 2 * (video BW + audio BW) < 900 | 11 |
If 900 <= 2 * (video BW + audio BW) < 1088 | 10 |
If 1088 <= 2 * (video BW + audio BW) < 3000 | 9 |
If 3000 <= 2 * (video BW + audio BW) | 5 |
To determine the resource capacity a standard MCU service uses, use the following algorithm:
where:
| Bandwidth Calculation | Call Weight |
|---|---|
If 100 <= 5 * video BW + audio BW< 528 | 12 |
If 528 <= 5 * video BW + audio BW < 678 | 11 |
If 678 <= 5 * video BW + audio BW < 928 | 10 |
If 928 <= 5 * video BW + audio BW <1228 | 10 |
If 1228 <= 5 * video BW + audio BW < 1628 | 9 |
If 1628 <= 5 * video BW + audio BW < 1728 | 11 |
Posted: Wed Sep 20 09:08:58 PDT 2000
Copyright 1989-2000©Cisco Systems Inc.