Finally ended up with these assumptions guyz...
Band Width Calculations:
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1. Web Browsing :
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// Assumptions :-
// Limited downloads and Low graphics web pages.
No. of simultaneous sessions : 500
Estimated bandwidth / user : 10 Kbps
Total Bandwidth : 500 * 10 = 5000 Kbps
(Margins are calculated on total bandwidth)
2. E-mail :
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// Assumptions :-
// Attachment size < 1 MB (since intranet usage only). Average size of E-mail is 3 KB.
// suppose each user send 10 Email per hour, 40% emails with attachment.
Bandwidth consumed by each user in 1 hr = (4*1000 + 6*3)*8
Required bandwidth per user : 32144/3600 = 8.9 kbps ~ 10 kbps
NO. of intranet e-mail sessions : 600
Total Bandwidth required : 600 * 10 = 6000 Kbps
3. Intranet FTP :
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No. of FTP sessions : 60
Bandwidth per user : 1 Mbps
Required Bandwidth : 60 Mbps
4.Video Streaming :
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// Assumptions :-
// Frames per second : 30
// Resolution : 320 x 240 Pixels
// Webcasting type video streaming
Estimated Bandwidth per session : 512 kbps (Moderate quality)
No. of video sessions : 6
Total Bandwidth required : 512 * 6 = 3072 Kbps ~ 3000 Kbps
5. VoIP calls :
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// Assumptions :-
// Codec G.711 – 64 kbps, 20 ms sample period
// 1 frames per packet (20 ms)
// Standard IP headers, Ethernet transmission medium
One packet is sent every 20 ms => 50 packets per second.
Payload is 64,000 ÷ 50 = 1,280 bits (160 Bytes).
Fixed IP overhead = 40 Bytes. Fixed Ethernet overhead 38 Bytes. Total size 238 Bytes.
Bandwidth required per session is (160 + 40 + 38) x 50 x 8 = 95.2 kbps.
No. of VoIP sessions : 4
Required bandwidth : 95.2 * 4 = 380 Kbps ~ 400 Kbps.
6. Others:
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// Assumptions :
// Other small bandwidth consumptions are included in the margins.
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FINAL SOLUTIONS :
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Total Backbone Bandwidth required : ( 5 + 6 + 60 + 3 + 0.4 )* 1.35 = 100 Mbps link.
Total ISP bandwidth required : (5 + 3 + 0.4) * 1.2 = 10 Mbps link (Dedicated Link required)
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References :
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VoIP Calculations : *www.newport-networks.com/pages/voip-bandwidth-calculator.html
Video Streaming : *sorenson-usa.com/vbe/index.html
bandwidth calculations: *www.busyaccess.com/calc.cfm
Bandwidth Statistics : *www.linktionary.com/b/bandwidth.html
