Questions tagged [osi]
For questions about the Open Systems Interconnect (OSI) model defined by the International Organization for Standardization (ISO).
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Why are large networks unable to rely solely on the use of physical addressing? [duplicate]
First of all, I would just like to point out just how new I am to the subject of computer networking. Therefore, I apologise if my question seems a poor one however I am currently unable to find an ...
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0answers
12 views
Benefits of encapsulation? [on hold]
Some benefits for encapsulation can include:
data can share network links since chunk of data is identified individually,
data can be flexibily routed over different routes,
encapsulation allows ...
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1answer
26 views
Whats the security difference between Policy Based IPSec VPN tunnel vs HTTPS + Basic auth
We have several customers with the same service installed within their DMZ. This service is a HTTPS server. The server does not have authentication, this is solved by configuring the NetScaler ...
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1answer
114 views
What's the meaning of `circuit level gateway`?
The proxy server is an important security function provided by the Internet "circuit level gateway". Its work is mainly at the session layer of the Open Systems Interconnection (OSI) model, which acts ...
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0answers
15 views
what protocols does EAP AKA use?
can someone please explain me what protocols does EAP AKA use with respect to the OSI model? (for example what protocol it uses in data link layer and what protocol in transport layer)
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2answers
39 views
LLC connections
TCP establishes a logical connection before sending data,where LLC connections are physical and are being held just between two computers,not more.
Is this correct?
If so,why LLC=LOGICAL LINK ...
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1answer
26 views
why can't we use the sequence number to distinguish them since every packet has a different sequence number? [closed]
It is a question from Networking stanford course.
A server typically listens for TCP connections on a particular port
(e.g. 80 for HTTP or 22 for SSH). Which fields can the server use to
...
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0answers
18 views
Which fields can the server use to distinguish packets for a particular client connection? [duplicate]
A server typically listens for TCP connections on a particular port (e.g. 80 for HTTP or 22 for SSH). Which fields can the server use to distinguish packets for a particular client connection?It is a ...
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2answers
830 views
At which OSI layer a user-generated data resides?
I am getting a bit confused about which OSI layer is being used to store user-generated data.
As far as I understand the process of encapsulation, the higher layers (starting with layer 7 - ...
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3answers
62 views
How to explain the data flow of OSI model layers in a single picture [duplicate]
Take an example of searching www.example.com in a web browser. I have some confusions at each layer and they are
We have opened a web browser and searched for www.example.com. Now, As far as I know, ...
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2answers
300 views
Do the concepts of IP address and network interface not belong to the same layer?
https://unix.stackexchange.com/a/508065/674
You are confusing the device driver layers and the IP layers of the
stack.
At the IP layer, 127.0.0.1 is just another IP address and treated the
...
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1answer
38 views
Message formatting and encapsulation
I've gotten confused when reading about encapsulation and the OSI and TCP/IP models. I first read about message formatting and encapsulation and the diagram I read showed:
Destination | Source
and ...
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1answer
52 views
OSI Model vs Network Model: Does It Matter Which One You Use?
The OSI (Open Systems Interconnection) model is comprised of the following layers:
7. Application Layer
6. Presentation Layer
5. Session Layer
4. Transport Layer
3. Network Layer
2. Data Link ...
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8answers
2k views
Using sound waves in layer 1
Is it possible, in theory, to use sound waves as the physical medium to transmit data over a network?
In other words, could you implement layer 1 of the OSI networking model using sound waves or am ...
6
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4answers
757 views
OSI layer of Neighbor Discovery Protocol
NDP operates using ICMPv6 and, even though ICMPv6 messages are encapsulated in payload field of IPv6 datagram, ICMPv6 and ICMP are usually considered as network layer protocols. At least, on Wikipedia ...
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1answer
36 views
Abstract service primitive
In SNMP RFC documents, often the concept of abstract service primitive (ASP) is used. What is ASP in fact ? I think it is also used in ISO OSI.
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3answers
373 views
Session layer vs Transport layer
It seems both do the same thing (or establishing a session between two hosts differs from establishing a connection between two?) So what exactly is the difference here that make us consider them as ...
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2answers
61 views
Do protocols ever have standards that affect multiple layers of networking?
I'm reading about higher-level protocols such as HTTP and SOAP (concerning the application layer at the highest level) in addition to lower-level ones such as TCP. So far these protocols concern only ...
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1answer
78 views
Where does DNS resolution fit within the TCP/IP stack?
I know that it's possible to whitelist/blacklist IP addresses (for example, only allowing a few external IP addresses to be contacted from within a VPN). But since IP address destinations are the ...
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1answer
205 views
Dependency between IEEE 802 and OSI model [duplicate]
My question is focussed on IEEE 802.11x for (WLAN) and 802.15.1 (Bluetooth)
Wikipedia and other sources underline, that the mentioned IEEE standards just define the PHY and MAC layer from the OSI ...
3
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1answer
609 views
Data link layer acknowledgement
I'm confused with some concepts please help me out,
Data link layer manage flow control hop to hop. Flow control requires acknowledgement receiving but If we observe data link layer header, it does ...
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1answer
35 views
Are there any network devices that can be configured to add information from one layer to another?
If I have a corporate network, no WWW Internet outside of it, only different subnets. Can a Cisco router or switch be configured to take information from one layer and embed it in another layer?
For ...
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3answers
101 views
What is the physical representation of the OSI model?
I read on the Internet that the NIC resides on the physical layer of the OSI model so what about the other 6 layers. I know what they actually do but i want to know how it's done. In other wards, what ...
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3answers
291 views
Do OSI and TCP/IP models use the same protocols?
OSI is known for using hundreds of protocols to do its job. Both OSI and TCP/IP have Transport and Network(Internet) layers where TCP and IP protocols work respectively. It is clear that TCP/IP model ...
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1answer
39 views
How to add new tasks to layers of OSI or TCP/IP?
Which software and hardware parts of a computer are responsible for adding or removing values to the initial payload of a data packet in every layer of OSI or TCP/IP model? In other words, which parts ...
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3answers
3k views
Is the addressing done at transport layer or network layer of OSI?
According to the OSI model, the transport layer divides the data into segments and then attaches the source IP and destination IP along with the port numbers. Also it is said that the network layer ...
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2answers
71 views
what are multiple formats of message when passed through all the TCP/IP layers
I was wondering how the message changes its form or structure while passing through multiple layers.
Consider host 'A' sending "Hello" as message to host 'B'.
So how it changes its form while ...
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1answer
281 views
How is Network Access Layer/Link Layer of TCP/IP model different from Layer 1 and Layer 2 of OSI?
I was reading CCNA R&S book by Todd Lammle, I saw this in the chapter TCP/IP Basics under Network Access/Link Layer
Advantage of this layer over Layer 1 and Layer 2 of OSI model is that there ...
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6answers
2k views
Why do we need FTP when there are layers to transmit data?
In OSI, there are layers for routing, encapsulating and transmitting the data. Then why do we need FTP?
I read the following definition of FTP in books:
FTP is used for transferring files on ...
4
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3answers
1k views
Error Detection across OSI layers confusion
Confusion:
How does the transmitter know that his information( bits in physical layer, frames in data link layer, packet in network layer ) was transmitted correctly to the receiver?
I know that in ...
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1answer
77 views
What requirements must general firewall/routing software meet, to make OSI 2 port mirroring work correctly?
The basics are obvious, but there are technical points of networking implication which I don't understand.
Some of these are general to networking, others general to all routing/firewall softwares ...
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2answers
2k views
What is the difference between TCP/IP protocol and TCP model?
We know that there are two models OSI and TCP model. But TCP/IP protocol is
different from TCP model as this protocol used in both OSI as well as TCP model. So why the two are named the same is ...
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3answers
962 views
Does the OSI model support connectionless communication in the transport layer? [closed]
In section 7.4.4.1.2 of ISO/IEC 7498-1:1994(E) it begins with:
In connectionless-mode, the Transport Layer provides the following
functions to support connectionless-mode transmission:
But many ...
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1answer
773 views
OSI model peer communication
"In OSI model, each layer provides a protocol to communicate with its peer. When a packet is transmitted by a layer, a header consisting of Protocol Control Information (PCI) is added to the data to ...
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2answers
196 views
Why Ethernet was chosen to be the primary protocol + why carrier ethernet was created?
I'm currently trying to investigate the extra benefit that Ethernet has to offer for the internet today.
As far as i investigated & know, Ethernet gives us a new hardware, cables and functionality ...
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1answer
2k views
Does the physical layer is OSI ISO model add any header?
According to OSI model, does the physical layer add any header to the date it receives from layer 2? Or is it simply sending the data frames it gets from layer2 as shown in the figure below?
Are the ...
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1answer
54 views
What are connectivity associations in LAN? - IEEE Std 802.1X-2010
In IEEE Std 802.1X-2010, Appendix D, Section D.8, there is the following phrase
However simple or complex, the establishment of a
connectivity association for connectionless data transfer ...
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2answers
517 views
OSI and TCP/IP: which is the relation? [duplicate]
In the "network" literature there are always explanations of this two reference models: OSI and TCP/IP.
The TCP/IP conceptual model is indeed a "fact" in terms of implementation. Anyone can find the ...
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2answers
1k views
Packet filtering firewall
I read that packet filtering firewall operates at level 3 (network layer). In the description I read that it filters packets based on IP addresses and ports.
If it's operating at level 3, how can it ...
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1answer
43 views
How will these frames be delivered to respective destination nodes? [closed]
I have the following 3 devices on my network(a bus topology): A,B,C
Let
MAC(i) - denote the MAC address of the device i.
IP(i) - denote the IP address of the device i.
The devices B and C happen ...
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1answer
74 views
In the MAC acronym what do the words Media, Access and Control refer to independently?
I am not a native English speaker and I know what MAC addresses are and how are they used in networks.
However what I do not understand is where this words came from independently.
What does Media ...
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1answer
43 views
Placing a “protocol” field in the IP header breaks the conceptual separation of interests that the OSI aimed for [closed]
I saw that while reading an answer about .. and now I'm confused.
4
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1answer
363 views
How does a NIC know where the start of a frame is?
A question popped into my head today and after a quick few searches on google, I have no idea. When a device is sent a frame there is a layer 1 header/preamble saying the length and layer 2 protocol (...
3
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3answers
194 views
TCP/IP protocol suite
I read that "TCP/IP protocol suite contains relatively independent protocols which can be mixed and matched which is not possible in OSI". What is the meaning of mix and match over here ? Can we mix ...
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1answer
246 views
OSI layer for promiscous / monitor mode
On what OSI layer do network cards operate when the use
promiscuous mode
monitor mode
?
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2answers
632 views
What is the difference between “Network Model” and “Network Architecture”?
I have a great confusion about the terms "Model" and "Architecture". Is the TCP/IP is a model or architecture?. If it is model then what is architecture? What does the both terms refers to.
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1answer
311 views
IP/TCP - most common use cases [closed]
What are the most common use cases for IP and TCP?
I am trying to find out what might be the best use cases for IP and TCP connections but unfortunately I wasn't very succesful so far.
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3answers
592 views
How nodes/switches communicate between each other?
fWe know that they only care about the first 3 layers of OSI-Model so when a node receive the data from a PC/Server, it goes up to layer 2 (Here is MAC address) and then it goes up to Network layer (3)...
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0answers
457 views
Question about the 7 layers of OSI Model [duplicate]
I just saw level 1-2-3-4 (from Physical to Transport)
We have the following :
The thing is: We know that at layer 3 there is the IP protocol that uses DNS Server to get the IP Address of the ...
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1answer
79 views
Why is local network communication handled differently to inter-network communication in the OSI model?
Looking at a Stack Overflow question - https://stackoverflow.com/questions/13006949/what-is-the-difference-between-the-data-link-layer-and-link-layer - one of the answers says that the data link layer,...
