Types of ethernet

Ethernet : having speed of 10 Mbps, alternate name 10baseT, name given by IEEE 802.3. Media used by this ethernet is copper cable having length upto 100m, means it can transmit data upto the lenth of 100 m distance.

FastEthernet : speed of 100 Mbps. Alternate name 100BaseTX, IEEE name 802.3u, it use Copper cable of 100 mtr. length same as ethernet.

Gigabit Ethernet : speed of 1000 Mbps, Alternate name 1000BaseLX and 1000BaseSX, IEEE name 802.3z, It use fiber cable, 550 mtr. (SX) and 5 KM (LX).

Gigabit ethernet : speed of 1000 Mbps, alternate name 1000BaseT, IEEE name 802.3ab. It uses copper cable having length of 100 mtr.

OSI Encapsulation

OSI defines the process by which a higher layer asks the services from the next lower layer. To provide the services , the lower layer encapsulates the higher layer's data behind the header.

OSI Model uses more Generic term called Protocol data unit ( PDU ). A PDU represents the bits that include the headers and trailers for that layer, as well as encapsulated data. The following diagram shows the process:

 

Figure - 1.1 OSI Model PDUs

TCP/IP model uses term segments, packets, frames and bits, in above figure.