The protocols serve to guarantee data transport. They represent in themselves "languages", with which different systems communicate with one another. Certainly, some protocols are involved in each communication process. According to the tasks performed by the protocols can be classified as follows;
Protocols for physical data transmission.
Protocol for finding the route of the packages and their transport.
Protocol for data transport.
services
Services make protocols available to an environment where they can perform tasks such as configuring network information, or preparing data to be sent to remote systems. Finding the dividing line between services and protocols is not always that easy. Thus, the Internet service is based on its own protocol (HTTP), while the Domain Name System (DNS) service uses the DNS protocol.
Today's widespread services include a large number of different tasks. Many of these tasks are guaranteed by more than one protocol, but are covered through several different services. This partially leads to a different performance of networks, user systems, users, and applications.
Network services are divided into three major groups:
Networking Services
Services for operating systems
Services for users and applications
Service Access Points
Every network communication needs to use some protocols in order to
Provide for data-free network transport. In order for the data to pass by
One layer in the respective service of the other layer should be addressed to the designated gates
For this purpose. These are also referred to as Service Access Points (SAP).
Gates and services
Ports are address fields, which are used in network protocols, so that data packets are assigned the respective services. Usable gates are counted as follows:
Ports 0 to 1024 are described as wellknown ports.
Ports 1024 through 49151 are summarized as registered port ports and are reserved through applications.
Ports up to 65535 are dynamic or private ports that are not used by standard services and can be addressed by the user themselves.
Some of the popular service ports are listed below:
FTP (File Transfer Protocol) 21, SMTP (Simple Mail Transfer Protocol) 25, Telnet 23,
POP (Post Office Protocol) 110, IMAP (Interactive Mail Access Protocol) 143,
SSH (Secure Shell) 22, HTTP (Hyper Text Transfer Protocol) 80, HTTPS443,
DNS (Domain Name System) 53, Simple Network Management Protocol (SNMP) 161.
LAN access procedures, Ethernet technology
Ethernet technology is today more prevalent in local networks. It is based on the new broadcast principles, which were then developed and standardized by IEEE. The architecture specified in section 802. IEEE for the Ethernet standard is based on assigning the functions of the two lower layers of the OSI model. For Ethernet, sections 802.1, 802.2 and 802.3 are significant, where general designations of the LAN architecture and LLC are available. Today, Ethernet is used for transporting various materials, as well as different speeds and ways to transmit data.
Community of TCP / IP protocols and tasks
The TCP / IP protocol community (TCP / IP-Protocol-Stack) includes a range of protocols that fulfill various network tasks. The common denominator of these protocols is all, for data transport use the Internet Protocol (IP) belonging to the OSI model layer layer (Network Layer). The following table gives a general overview of the most important protocols protocol (protocol protocol stack).\
ICMP's accumulation in the Internet layer is the result of protocols tasks. Even if ICPM is assigned to its own IP-SAP, it is still found in the Internet layer. The classification of ARP / RARP as part of the layered model is not so simple as the protocols perform a Network Layer information classification with the Data Link Layer information. They are referred to as the sub-protocols of LLC and are thus placed in the layer layer layer.
| Application Layer | Telnet, FTP, TFTP, HTTP, LDAP, DHCP, BOOTP, DNS, POP, NETBIOS, SMTP ... | |
| Host-to-Host Layer | TCP | UDP |
| Internet Layer | | ICMP |
| IP | ||
| Network-Interface Layer | ARP, RARP | |
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