Ethernet Overhead Article no. 5382

Introduction

Ethernet Overhead

Ethernet is how we have delivered Internet service since Dial-up accounts. Ethernet connectivity is frequently referred to as 10/100 or 10/100/1000 Ethernet. These numbers indicate speed limits that Ethernet has always had as a networking protocol. These limitations happen more because of physical hardware more than software.

These speeds are raw concepts which mean that nothing ever sees the full capacity of the speeds advertised.

Resolution Steps

How does this affect us?

• Ethernet overhead is why we can never experience greater then 92 Meg out of a 10/100 Linksys e1200 router or a full Gigabit from a cable modem to a single Internet device
   
• Ethernet overhead is a universal networking concept that affects all providers
   
• For example, when we say this speed, after overhead we mean this speed:
  
   

  Stated Ethernet Speed	Usable Speed
  10m	8-9m
  100m	90-92m
  1000m	850-900m

  
  
  As you can see above, the advertised maximum speed is never available. This is because the additional bandwidth is taken up by packet buffers and other needed pieces of information.