Encapsulation of Protocols

Encapsulation and bytes overhead of protocols related to ISO/OSI reference model…

UDP@L4

                                 ------------------
064b (08B)                       | UDP |   Data   |
..........                  -----------------------
160b (20B)                  | IP |      Data      |
..........            -------------------------------------------
192b (24B)            | ESP |        Data         | ESP trailer |
..........       ------------------------------------------------
160b (20B)       | IP |           Data            |
.......... ------------------------------------------------
208b (26B) | Eth |              Data              | CRC32 |
.......... ------------------------------------------------
784b (98B) ... Total ...

TCP@L4

                                 ------------------
160b (20B)                       | TCP |   Data   |
..........                  -----------------------
160b (20B)                  | IP |      Data      |
..........            -------------------------------------------
192b (24B)            | ESP |        Data         | ESP trailer |
..........       ------------------------------------------------
160b (20B)       | IP |           Data            |
.......... ------------------------------------------------
208b (26B) | Eth |              Data              | CRC32 |
.......... ------------------------------------------------
880b (110B) ... Total ...

Technically, there is an IFG (12B) following the CRC32 field. Considering that IEEE 802.1Q is not used, the minimum size of the Data field within the Ethernet frame is 46B and the maximum size is 1500B.

Calculation of the Ethernet overhead:

Overhead = (FrameSize - Data) / FrameSize

Calculation of the size of an Ethernet frame:

FrameSize = Preamble + SoF delimiter + MAC dest + MAC src + Ethertype/length + Data (Payload) + FCS + IFG 

Ethernet protocol overhead for minimum size of Data:

Overhead_dsmin = (7+1+6+6+2+46+4+12 - 46) / (7+1+6+6+2+46+4+12) ~ 0.452 ~ 45.2%

Ethernet protocol overhead for maximum size of Data:

Overhead_dsmax = (7+1+6+6+2+1500+4+12 - 1500) / (7+1+6+6+2+1500+4+12) ~ 0.025 ~ 2.5%
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