Short notes of OSI layers

Layer7(Application):

To allow access to network resources.

e.g: Telnet, FTP. NFS, NIS

Layer6(presentation):

To translate encrypt and compress datas.

e.g: jpeg, mpeg

Layer5(session):

To establish, manage and terminate sessions.

e.g: RPC

Layer4(Transport):

To provide reliable end to end message delivery and error recovery. e.g: TCP, UDP

Layer3(network layer):

To move packets from source to destination to provide internetworking.

e.g: ip, ARP/RARP/ICMP

Layer2(datalink layer):

To organize bits into frame to provide node-to-node delivery.

e.g:ethernet, FDDI, PPP, HDLC

Layer1(physical layer):

To transmit bits over a medium to provide mechanical and electrical specifications.

e.g: Fiber, coax, 100baseT