The five layer TCP/IP model 
5. Application layer 
DHCP • DNS • FTP • HTTP • IMAP4 • IRC • NNTP • MIME • POP3 • SIP • SMTP • SNMP • SSH • TELNET • BGP • RPC • RTP • RTCP • TLS/SSL • SDP • SOAP • L2TP • PPTP • … 
4. Transport layer 
3. Network layer 
IP (IPv4 • IPv6) • ARP • RARP • ICMP • IGMP • RSVP • IPSec • … 
2. Data link layer 
1. Physical layer 
Ethernet physical layer • ISDN • Modems • PLC • RS232 • SONET/SDH • G.709 • WiFi • … 
Archive for ELearning
OSI basic
Logical shift and operation
It calls that all bit of binary is shifted on left and right logical shift. When it shifts logically, value changes as description below.
On the left n bit shift: It becomes 2 ntuple
On the right n bit shift: 2 the ntuple (the value which is divided with 2n) it becomes
Therefore, the bit just is shifted can do multiplication and division.
Example: Binary “0101” on the left 2 bit shifts
(The result which is shifted 2 ntuple (4 times) verification the thing which becomes)
Binary 

When it converts to decimal, “0101” > “5”
Binary on the left 2 bit shifts 

2 bits it shifts to the left, it inserts “0” into the bit which is less crowded
The result and 2 ntuple (4 times) “20” you can verify that is
Then, it will try solving the problem of logical shift and operation.