Bandwidth calculation for Voip + Video Surveillance cameras

Hi Guys!

We hav a customer who has 150 sites which needs to be connected through satellite .Now the applications which customer needs to run on this network includes

1) Voip
2) Video Surveillance streaming video (traffic monitoring cameras)
MPEG4 format + 320*240 resolution + 30FPS ( frames per sec ) .

Now these two types of traffic needs to be transported from remote locations through satellite to HQ .Now i have to calculate Download and upload data throughput for which to calculate the Link Budgets .I wana know how can i estimate the D/L , U/L bandwidth ?
Customer provides following info .

1) Voip calls ( SIP based , G.729a codec , 5X5 )

5 X 5 means 5 simultanous calls of 5 min each , per hour

2 ) traffic monitoring cameras, MPEG4 format + 320*240 resolution + 30FPS ( frames per sec )

How can i calculate (estimate total upstream and downstream bandwidth for which i hav to design the network ?
Any Help will be appreciated.

Rgds
Taqqi

Hi Taqqi,

I'll try to tackle the VOIP bit.

Your customer has stated that the requirements are:
- Sip Based
- G.729a Codec (8kb/s)
- 5 x 5 - five calls of five minutes per hour

a) Peak Call Rate
============
My first observation is that the 5x5 is meaningless. this look like an average call rate estimation and what you need is the peak demand

For example an average of 5x5 could indicate the peak is all 5 calls simultaniously for 5 minutes...or they could be spread out nicely.

So I would assume the peak to be 5 calls of 5 minute simultanously for this example.

b) CODEC
=======

We know from the customer the codec to be used is G729a. This is a 8kb/s codec, which samples 10 milliseconds of voice per frame.

c) Headers
========

In a typical scenerio there will be 3 headers involved : IP(20 bytes), UDP(8 bytes) and RTP(12 bytes). Or 320 bits per packet. The packet can contain a single voice sample or multiple voice samples.


Now lets figure it out the bandwidth needed.

Firstly we need the number of voice sample per second:
Second / voice sample = no of samples
1000ms / 10ms = 100 samples

Now figure out the overhead:
no of samples x 320 bits = overhead
100 x 320 = 32 000 bits = 32kb/s

Total bandwidth per sample:
overhead + codec = total BW
32 Kb/s + 8 Kb/s = 40 Kb/s

Now let's apply this to our busiest traffic time as stated earlier

5 simultanous calls x 40Kb/s = 200Kb/s

so by my reckoning your customer will need a min of 200kb/s to ensure the potential peak traffic can be accomodated. This could be reduced by better understanding the traffic profile for the calls between sites, and by increasing the number of samples per packet.

I hope this makes sense!

(thanks to www.snom.com/wiki/index.php/Bandwidth_requirements_and_QoS for help)

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