2-6CHAPTER 2: LAN EMULATION OVERVIEW

Packets Versus Cells The ATM Backbone SwitchModule converts Ethernet- and FDDI-originated packets to and from ATM cells.

Figure 2-6 illustrates the conversion of SwitchModule packets to and from ATM cells.

SwitchModule packet

From

ATM

Padding and error correction

Segmentation/

Reassembly

48 Octets

Cells

HDR

 

 

 

 

 

 

 

 

 

 

 

 

53 Octets

 

 

 

 

 

 

 

48 Octets

HDR

53 Octets

48 Octets

HDR

53 Octets

To ATM

HDR = ATM Cell Header (5 octets)

Figure 2-6Converting SwitchModule Packets to and from ATM Cells

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3Com 5000 ATM manual 6Converting SwitchModule Packets to and from ATM Cells