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