TCP/IP Model:
à TCP/IP Model also known as Department of Defense (
DOD) model , was created by the DOD.It consisting of four layers
- Application Layer === Application + Presentation + Session Layer of OSI model.
- Host to Host Layer ==== Transport Layer of OSI model.
- Internet Layer ===== Network Layer of OSI model
- Network Access ==== Data Link + Physical Layer of OSI model.
Application Layer:
à Application Layer of TCP/IP model combines the
functionalities of top three layers of OSI model.
à Application Layer provides services to the application
software such as web browser.
à Basically it provides interface between applications
running on the computer and network.
Transport Layer:
à Transport Layer of TCP/IP model having the same
features of OSI Layer model and it is also known as the Host to Host layer.
à Transport Layer basically uses two protocols known
as
1) Transmission
Control Protocol (TCP)
2) User
Datagram Protocol ( UDP)
à There are lots of differences between TCP and UDP.
TCP
|
UDP
|
1. Connection oriented Protocol
|
1. Connection less protocol
|
2. Reliable
|
2. Unreliable
|
3. Slower data transfer speeds
|
3. Faster Data transfer speeds
|
4. Complicated Header
|
4. less complex
|
5. Used in many applications.
|
5. Used in fewer applications.
|
6. Used in Downloading, mail
|
6. Used in video and voice
applications.
|
7. ex: HTTP,FTP,HTML,SMTP
|
7. ex: TFTP,DNS,DHCP
|
8. Port number: 6
|
8. Port number : 17
|
9. Retransmission possible
|
9.Retransmission not possible
|
Note: we need to
memorize TCP header format and UDP header format for the CCNA exam. Which
application is using TCP and which application using and their port numbers
need to be remembered.
TCP Applications:
- FTP===============20,21
- Telnet==============23
- SMTP==============25
- DNS=============53
- HTTP============80
- POP3============110
- HTTPS===========443
- NNTP============119
UDP
Applications:
- DHCP=======67,68
- DNS========53
- TFTP========69
- NTP=========123
- SNMP========161
Note: DNS is used by
both TCP and UDP.
Figure: TCP Header
Internet Layer:
à
Internet Layer of TCP/IP model is similar to Network
Layer of the OSI layer model.
à
IP, ICMP,ARP,RARP and Proxy ARP are the
protocols used in the Internet layer.
Network Interface Layer:
à
Network Interface layer combines the
functionalities of both data link layer and Physical layer of the OSI layer.
à
Ethernet
, PPP , Token Ring and FDDI are the protocols used in this layer.
Sir, you're remembering me DNS used both tcp & udp protocols, it had slipped my mind.
ReplyDeletePlease sir, some details given Proxy ARP about..