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