In networking and communications, a protocol is the formal specification that defines the procedures that must be followed when transmitting or receiving data. Protocols define the format, timing, sequence, and error checking used on the network.
In plain English, the above means that if you have two or more devices that want to communicate, they need a common protocol, or set of rules, that guides the computers about how and when to talk to each other.
Protocols are defined by RFCs (requests for comments), in which the IETF maps out the new standard or protocol. Vendors (IBM, Cisco, Microsoft, Novell) then follow these standards and implement them in their products.
There are hundreds of protocols out there, and it is impossible to list them all here. Instead we have included the most common and will follow up with more specialized protocols in future articles.
The table below shows the most popular TCP/IP protocols. The OSI model shows at which layer each of these protocols works.
One thing to keep in mind is that as you move from the lower layers (Physical) to the upper layers (Applications), the device that's dealing with the protocol will require more processing time.
TCP/IP protocol stack ..................The OSI model
The series focuses on all things IP...
Lesson 1: Introduction to IP
Lesson 2: Binary and the Internet Protocol
Lesson 3: The Internet Protocol (IP) header
Lesson 4: Internet Protocol classes - Network and host ID
Lesson 5: Introduction to subnetting
Lesson 6: IP subnetting - The basic concepts
Lesson 7: Subnet masks and their effect
Lesson 8: Subnetting analysis
Lesson 9: Subnet routing and communications
Lesson 10: Subnetting guidelines
Our next series will focus on:
TCP
UDP
ICMP
DNS
FTP
TFTP
Ethernet
RIP
OSPF
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