How Ethernet frame sizes are defined

Two commonly used terms to describe frame characteristics are frame size and Maximum Transmission Unit (MTU) size.

The frame size of a standard Ethernet frame (defined by RFC 894) is the sum of the Ethernet header (14 bytes), the payload (IP packet, usually 1,500 bytes), and the Frame Check Sequence (FCS) field (4 bytes).

The MTU size specifies the maximum number of bytes of data (the payload) that can be encapsulated in an Ethernet frame. For example, the MTU size of a standard Ethernet frame is 1,500 bytes; this is the default for your storage systems. However, a jumbo frame, with an MTU size of 9,000 bytes, can also be configured.

• Benefit of increasing Gigabit Ethernet frame sizes
  Increasing the default frame size for any Gigabit Ethernet interface supported on your storage system, as well as the Gigabit Ethernet infrastructure to which it connects, can significantly increase performance depending upon the activity.
• Benefit of using jumbo frames
  You might want to reduce your CPU processing by using jumbo frames with your network interfaces. Because jumbo frames are larger than standard frames, fewer frames are needed and therefore CPU processing overhead is reduced.
• Flow control
  Flow control is the management of the flow of frames between two directly connected link-partners. To achieve flow control, you specify a flow control option that causes packets called Pause frames to be used as needed.