Which of the following are connectionless protocols on the OSI model at the network layer?
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First, the OSI model is just a model, and things in the real world do not necessarily match. In particular, OSes, do not implement the Session and Presentation layers separately from the Application layer. Show
The network (Internet for the TCP/IP model) layer is connectionless. The two most-used transport protocols are TCP and UDP. TCP is connection-oriented, but UDP is connectionless. Since the OSI model is an ISO standard, the ISO/IEC wording is what you should go by. As you read in the ISO/IEC 7498-1:1994(E), the Transport Layer is defined as both connection-oriented and connectionless. There are explanations about using it both ways (I highlighted the relevant text in this section, but the entire document speaks to connectionless-mode):
The ISO definition of the OSI model is the definition of the OSI model. Anybody else who writes anything that disagrees with the ISO definition is making up something that is not the OSI model. Just because it is published in a web page does not make it true. It is true only if it agrees with the ISO definition of the OSI model. Edit: I found a paper that lays out the update discussions to the original OSI model. It appears that in the original model, there was no connectionless mode, even in the Network Layer. In any case, this was all hashed out well before the Internet went commercial in 1995, and any web sites that claim the Transport Layer cannot use connectionless protocols are simply incorrect. The current OSI model, available since before the Internet went commercial, has always included the connectionless mode. It's like reading the reports by doctors from the 1940s and 1950s claiming that smoking is good for you. I know people who still quote those doctor recommendations. Networking moves orders of magnitude faster than medicine, and the original OSI model was out of date before the Internet went commercial; it has been obsolete for 24 years. and anyone who cares about the original version far out of touch with reality. Connectionless communication, often referred to as CL-mode communication,[1] is a data transmission method used in packet switching networks in which each data unit is individually addressed and routed based on information carried in each unit, rather than in the setup information of a prearranged, fixed data channel as in connection-oriented communication. Attributes[edit]Under connectionless communication between two network end points, a message can be sent from one end point to another without prior arrangement. The device at one end of the communication transmits data addressed to the other, without first ensuring that the recipient is available and ready to receive the data. Some protocols allow for error correction by requesting retransmission. Internet Protocol (IP) and User Datagram Protocol (UDP) are connectionless protocols. A packet transmitted in a connectionless mode is frequently called a datagram. Connectionless protocols are usually described as stateless protocols because the end points have no protocol-defined way to remember where they are in a "conversation" of message exchanges. Connectionless communication has lower overhead than connection-oriented communication because in connection-oriented communication the communicating peers must first establish a logical or physical data channel or connection in a dialog preceding the exchange of user data. Connectionless communication allows for multicast and broadcast operations in which the same data are transmitted to several recipients in a single transmission. In connectionless transmissions the service provider usually cannot guarantee that there will be no loss, error insertion, misdelivery, duplication, or out-of-sequence delivery of the packet. However, the effect of errors may be reduced by implementing error correction within an application protocol. In connectionless mode there is less opportunity for optimization possible when sending several data units between the same two peers. By establishing a connection at the beginning of such a data exchange the components (routers, bridges) along the network path would be able to pre-compute (and hence cache) routing-related information, avoiding re-computation for every packet. In connection-oriented communication, network components can also reserve capacity for the transfer of the subsequent data units of a video download, for example. Architecture and implementations[edit]Distinction between connectionless and connection-oriented transmission may take place at several layers of the OSI Reference Model:
Notable connectionless protocols are: Internet Protocol (IP), User Datagram Protocol (UDP), Internet Control Message Protocol (ICMP), Internetwork Packet Exchange (IPX), Transparent Inter-process Communication, NetBIOS, and Fast and Secure Protocol (FASP). References[edit]
Which of the following is a connectionless network layer protocol?UDP is a connectionless protocol. No connection needs to be established between the source and destination before you transmit data.
Which of the following protocols are connectionless?Internet Protocol (IP) and User Datagram Protocol (UDP) are connectionless protocols.
Which of the following protocols work at the network layer of the OSI model?The network layer assists the following protocols: Internet Protocol (IPv4), Internet Protocol (IPv6), IPX, AppleTalk, ICMP, IPSec and IGMP.
At which layer of the OSI model will you find connectionless communication?Layer 3 transmissions are connectionless, or best effort - they don't do anything but send the traffic where it's supposed to go. More on data transport protocols on Layer 4. Once a node is connected to the Internet, it is assigned an Internet Protocol (IP) address, which looks either like 172.16.
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