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VoIP Bandwidth

Pick the codec, the concurrent calls, the packetization and the layer-2 overhead and get the per-call and total bandwidth of your VoIP trunk. Includes header compression (cRTP) and a codec comparison table.

How many ms of voice travel in one packet. Fewer ms = more packets per second (pps) = more overhead.

Compresses the RTP+UDP+IP headers on point-to-point links (typical on serial WAN). Greatly reduces per-packet overhead.

redzilla.cl — voip 
 
  
 
 
Per call
 
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Trunk total
 
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Packets per second
 
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per call
 
 
  
 
 Per call —  
 
 Total —  
 
 Packet —  
 
  
 
Bandwidth by codec
 

With the selected packetization and overhead. The highlighted row is
          the chosen codec.

 
 
  
CodecPayloadkbps/callTotal
   
 
 
 
 How it is calculated · payload, headers and pps 
 
 1. pps = 1000 / ms. With 20 ms
            of voice per packet that is 50 pps.

 
 2. payload (B) = (codec_bps / 8) × (ms / 1000).
            G.711 at 64 kbps with 20 ms = 160 B.

 
 3. Headers per packet:
RTP+UDP+IP = 40 B (or ~2 B with cRTP) plus
            the layer-2 overhead (Ethernet=18 B,
+VLAN=22 B, MPLS=4 B).

 
 4. bw_per_call (bps) = (payload + headers) × 8 × pps.
            The total = bw_per_call × number of calls.

 
 
 
 
 
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