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VoIP Packet Overhead

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The world of packet overhead, the envelopes which ensure our information reaches our destination.

It is easy to forget these specific values however they can be necessary to engineer WAN links for client VoIP deployments.

The following is a summary of common overhead values for your ease of reference.

I will attempt to update this page with pertinent ‘overhead’ related information over time.

Comment below with any suggestions you may have and I will try my best to add them.  Thanks.


Standard Layer 2 Voice Packet Overhead

Ethernet II:
18 Bytes

Ethernet (with 802.1Q) VLAN Tag:  22 Bytes

Frame Relay Forum Standard 12 (FRF.12):  6 Bytes

HDLC:  7 Bytes

MPLS: 4 Bytes

PPP: 12 Bytes

MLP:  6 Bytes

ATM:  5 Bytes

IPSec:  50 – 57 Bytes

L2TP / GRE:  24 Bytes


Standard Layer 3+ Voice Packet Overhead

RTP: 12 Bytes

UDP: 8 Bytes

IP: 20 Bytes

Total:  40 bytes

Note:  Compressing the above header using cRTP can bring the 40 bytes down to 2-bytes of overhead (4-bytes if UDP checksum is being used).

Common CODEC Types and their Associated Payload and Packet Sizes

CODEC Payload Size and Type

Standard Voice CODEC Payload Sizes and Types

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About Behzad Munir

Behzad Munir, P.Eng, is a Voice Solutions Consultant working in Toronto, Canada

voip phone service 01
voip phone service 01

Informative article! understanding this figures is very important if got voip service.

Richie Mordue
Richie Mordue

Appreciate it for helping out, fantastic info .

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