protocols in osi model

What are protocols in osi model

The osi model is the reference model for developing network protocols. In this tutorial we will discuss about the protocols used in each layer of osi model.  When a protocol is developed according to OSI model, first thing is, which OSI layer will provide the service to the new protocol? The layer selection will be based on the functionality and the network requirements. For example , if you  want to develop a network protocol which needs only routing functionality for IP packets.   Then this will be above the Network layer of OSI model and if it needs connection oriented delivery of messages the new protocol will be above the transport layer of OSI model.  Following is a list of protocols along with the OSI layer they belongs too.

DHCP osi layer :

DHCP is an application layer protocol. In real implementation , DHCP works over TCP/IP protocol.  The full form is Dynamic Host Control Protocol. When a network connection comes up. Computer needs and IP address to work in computer network. The computer which is connecting to the computer network works as DHCP client. It request to the server , to get the IP. You might have seen while configuring IP address for the Ethernet card or LAN card on Window machine.  The internet router works as DHCP server in this case.

ARP osi layer :

ARP stands for Address Resolution Protocol. It resolves an IP address to the MAC address of the Ethernet card.  ARP is the data link layer protocol in osi model.

DNS osi layer :

This is domain name system.  It is an application layer protocol.

ICMP osi layer:

It works as user of IP layer. ICMP routes protocol messages to the remote end using IP layer protocol.  As this provides a service to end user so it is an application layer protocol.

udp osi layer:

UDP is a transport layer protocol. This is data gram protocol , where no connection is setup. Not reliable , but good for real time delivery. It is a transport layer protocol

tcp osi model:

It is another example of layer four (transport layer ) protocol. It is a relational protocol.

ss7 and osi model:

SS7 itself have many layers. Following is the tabular mapping of ss7 protocol layers with the osi model.

SS7 Layers OSI  layers
MTP1 Physical Layer
MTP2 Data Link Layer
MTP3 Network Layer
SCCP Transport Layer
TACP, ISUP Session Layer and Presentation Layer
MAP, INAP , Camel Application Layer

Telnet and osi layer:

Telnet is an application layer protocol of osi model. It is for remote operations over computer network. Uses TCP/IP for transport of telnet protocol messages.

SIP and osi layer:

Sip is session initiation protocol used in VoIP network. This belongs to the application layer of OSI.

IP and osi layer:

IP is Internet Protocol, it is a layer 3 protocol example of OSI model. IP uses services of data link layer and provides services to the transport layer.  At transport layer examples are SCTP, TCP, UDP etc.


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