1.0 Network+ Certification Cram Notes : Networking Fundamentals

1.5 Common ports and protocols, their application, and encrypted alternatives

Explain the following IP protocol types

1. Internet Control Message Protocol (ICMP) - ICMP is a network protocol used to send error messages or to provide information about network conditions. It is commonly used for diagnosing network problems and measuring network performance.

2. Transmission Control Protocol (TCP) - TCP is a reliable, connection-oriented protocol that is used to transmit data over a network. It establishes a reliable, two-way communication channel between two applications and ensures that data is delivered accurately and in the correct order.

3. User Datagram Protocol (UDP) - UDP is a simple, connectionless protocol that is used to send data over a network. Unlike TCP, it does not guarantee the delivery of data or guarantee that data will be received in the correct order.

4. Generic Routing Encapsulation (GRE) - GRE is a protocol that is used to create a virtual private network (VPN) over an IP network. It enables data to be transmitted securely between remote networks by encapsulating the original data within a GRE packet.

5. Internet Protocol Security (IPSec) - IPSec is a set of protocols that provide security for IP-based networks. It includes two main protocols: Authentication Header (AH) and Encapsulating Security Payload (ESP). AH provides authentication for the data being transmitted and ESP provides both authentication and encryption for the data.

1. Authentication Header (AH) - AH is a protocol used in IPSec to provide data authentication. It ensures that the data being transmitted has not been altered in transit and that it came from the original sender.

2. Encapsulating Security Payload (ESP) - ESP is a protocol used in IPSec to provide data encryption and authentication. It protects the data being transmitted from unauthorized access and ensures that the data has not been altered in transit.

Connectionless vs. connection-oriented

The terms "connectionless" and "connection-oriented" refer to two different types of data transmission protocols.

In a connectionless protocol, data is sent as individual packets with no guarantee of delivery or order. These protocols are often used for broadcast or multicast applications, where the data is sent to multiple recipients and the loss of a few packets is not critical. Examples of connectionless protocols include the User Datagram Protocol (UDP) and the Internet Control Message Protocol (ICMP).

In a connection-oriented protocol, a reliable and ordered data transmission is established before the actual data transfer takes place. This is accomplished by establishing a virtual circuit between the sender and receiver. The virtual circuit provides a reliable and ordered delivery of data packets between the two endpoints. Examples of connection-oriented protocols include the Transmission Control Protocol (TCP) and the Stream Control Transmission Protocol (SCTP).

In general, connection-oriented protocols are more reliable than connectionless protocols, but they are also slower and less efficient, due to the overhead involved in establishing and maintaining the virtual circuit.