Questions tagged [computer-networks]
Questions about problems that arise when you connect multiple computers to form a network.
348
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IP Fragmentation
I have an IPv4 packet, 3523 byte of information Data a MTU (maximum transmission unit) of 516 (496 byte + 20 byte IP header), also an TCP header with 20 byte.
How does this result is created from the ...
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TCP Connection Termination - FIN, FIN ACK, ACK
I've been reading that to terminate a TCP connection 3 handshakes are required: FIN, FIN ACK, and ACK. However, when closing a connection, Wireshark displays FIN ACK, FIN ACK, ACK; it never displays ...
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Hashing methods for validating dowloaded files
The standard algorithm to generate hashes of files which are downloaded is MD5. For example, when ISO files of Linux distributions are offered most of the time they also give the MD5 sum so that you ...
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Difference between Bandwidth and Propagation Speed in computer networks?
I want to know the difference between Bandwidth and propagation speed. How are they associated with each other i.e. the impact on bandwidth if propagation speed varies or the impact on speed if ...
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Combine the following IP Addresses into a single block
I was asked to combine the ip addresses into a single block:
16.27.24.0/26, 16.27.24.64/26, 16.27.24.128/25
I managed to convert the given ip addresses into binary:
00010000.00011011.00011000....
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Go-Back-N ARQ Protocol Throughput Question
I am an undergraduate studying Data Coms and Networking and this question about go-back-N ARQ popped up that I am struggling to get my head around and cant find anything similar online. Any help at ...
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Lower limit on the number of check bits needed to correct single errors
I was going through Andrew S. Tannenbaum's computer networks book, and on page 206 of it, he has derived the number of check bits needed to correct single bit errors. The derivation goes as follows:
...
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What are networking technologies to distribute the file faster with storing on more replicas?
Question: Suppose you launch a job on 10,000 machines in your own data centre. The job is slow to start because all the machines are trying to load the same large executable file. Name two networking ...
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Do networking ports come from "port-mapped I/O"?
Do networking ports come from "port-mapped I/O"?
I was watching a hardware basic video by Brian Will:
https://www.youtube.com/watch?v=9-KUm9YpPm0
And they brought up this concept at 18:15
...
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Paris-Traceroute and Traceroute Difference
I am trying to understand the difference between Paris-traceroute and normal traceroute.
I am using this website ( https://paris-traceroute.net/about) and trying to get the idea, what is Paris-...
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New Idea for accessing memory across an inter-network connected system
I have the following idea for a network-based operating system.
Suppose we have two computers A and B in a network. If computer B wants to access the memory of computer A, it can access by using the ...
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2
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If all frames are naturally broadcast in a LAN, what is the need for a broadcast address?
The Ethernet MAC address FF:FF:FF:FF:FF:FF is reserved for broadcasts. If all frames are naturally broadcast in a LAN, what is the need for a broadcast address?
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Which one should I report as total network I/O bytes among Sum(InBound) or Sum(InBound + OutBound)?
I have a set of experiments with distributed environments.
I am planning to present a total network I/O bytes usage of the system for each run.
Which one should I report as total network I/O bytes ...
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Do we include Transmission delay in Round trip time?
Is RTT = $2*T_{Propagation delay}$ only. Or we include Transmission delay to send packets as well. Some examples include Transmission delay some not. I'm confused. Can anyone help.
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Polynomial generator required to detect single bit error in Cyclic Redundancy Check codes
I was reading about CRC coding from two books:
Data Communication and Networking by Forouzan Page 294
Computer Network by Tanenbaum Page 188
They use following notations:
$d(x)$: dataword to be ...
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We can control tcp/udp traffic using router. Then why is it in Network layer and not transport layer?
Routers make use of the IP address, etc to shape the traffic. So obviously they must reside in at least the Network layer.
However we can also shape the traffic using tcp/udp. Routers usually have the ...
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Sliding Window Protocol, waiting Time calculation
With regard to this explanation in finding Round Trip Time I tried attempting the following question
Question
Frames of $1000$ bits are sent over a $10^6$bps duplex link between two hosts. The ...
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transmission delay in store and forward, what is L/W and how to compute tw [closed]
I don't understand some things in Store and Forward equation:
D -> Number of channels and switches pairs.
tr -> Routing time.
tw -> Transfer time in a channel.
What is the L/W?
And normally ...
2
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1
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337
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Why is ARP needed in a host - router system if the router already has list of addresses it assigned using dhcp?
The hosts are assigned IP address by the router using dhcp. So, the router has a list (mac addresses) of all the hosts that are directly connected to it as well their ip addresses.
Now if a packet ...
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Relationship between flow and resource consumption in VNFs (Middleboxes)
A middlebox consumes some resources (CPU ticks, RAM, etc.) to process a traffic, e.g., a IDS consume 50% CPU and 20% RAM to process a 100M bps flow.
Here is the problem. 100M bps flow may consume ...
1
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1
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clarification on multiple access in data link layer
In physical layer, we already have methods to share a common link by dividing into channels using FDM etc.
Then why do we need to think about multiple access at data link layer? I.e why csma, csma/...
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How does a remote connection knows it's endpoint inside a LAN?
I'm very curious about anything related to packet headers since im not well aware of how TCP/UDP protocols identify it's connection endpoint after a public IP is addressed. As for today I know the ...
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Data link layer Sliding Window utilization formula query
In the data link layer, the Sliding Window is used for flow control.
There are two link utilization formula that can be use. They are :
U = 1, for N > 2a + 1
OR
U = N/(1+2a), for N < 2a + 1
In ...
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0
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Authority section in DNS packet always contains NS records?
I'm new to DNS and I'm trying to understand the DNS packet format. From what I understand, the authority section of a DNS packet gives information about servers that are authoritative for the domain ...
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0
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fundamental doubt in definition of routing table
I have some very simple doubt in definition of routing table, and would be thankful if anybody could clarify it.
The doubt is that can the routing table of any node, say w, be smaller than the degree ...
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The throughput of the ALOHA protocol if the Binomial distribution was used
In all the examples of ALOHA I've seen, the Poisson distribution is used. Theoretically, how could the throughput be calculated if a Binomial distribution was used instead?
For example, in the case ...
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Two word computer term ending in word "complex" meaning computers connected together
I remember seeing a Computer Science jargon which means multiple computers connected together; a network. It ends in the word "complex" and the first word (I cannot remember this but I shall guess to ...
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Practical communication example for a data rate scenario
Having difficulty with the following question.
I can answer parts I and II but having trouble finding a practical example.
Question:
Compute the maximum data rate of the following communication links;...
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How does the destination IP address go from Application\End to End Layer to the Network Layer?
If the TCP segment does not contain the destination IP in its header, how does the(first) network layer decide the first link to traverse, to get closer to the destination IP.
I have learnt that the ...
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How to ensure connectedness in a masterless gossip protocol?
This is a theoretical question about how gossip protocols work; I am not asking about any specific implementation or piece of software.
I've read the wikipedia page https://en.wikipedia.org/wiki/...
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Proof of Diameter of a network topology [closed]
How do I prove that diameter of undirected Ring Topology is n/2?
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Compute RTT in theoretical system
This is problem from my Networks class. It wants us to compute the round trip time of a point-to-point network and I'm just not sure which information is pertinent. The question:
NASA deployed ...
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Can queueing model capture insights of a system in terms of CPU utilization & service delay? [closed]
After some efforts, I'm really doubtful about the application of that queueing model in analyzing network servers (specially in my case, IP Multimedia Subsystem) as well as predicting the workload. ...
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Link utilization of sliding window protocol
Before I ask my doubt I would like to state that problem which led me to my doubt. It can also serve as a good example scenario.
A $20\ Kbps$ satellite link has a propagation delay of $400\ ms$. ...
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Role of network layer in Routers
I just started reading communication networks.
Now, routers contain the network layer, data link control layer and physical layer.
That being true I am confused as to why the network layer is ...
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How would the Internet work between planets?
Say that in the future there are people on other planets, e.g., Mars. The one-way communication delay to Mars is between 3 and 21 minutes.
Say we want to connect the people on Mars to the Internet. ...
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How does TCP manage to discard segment received from a source other than the one with which the connection has been established?
It is known that TCP is a connection oriented transport layer protocol of the TCP/IP suite. But TCP (and UDP) operate over a connection less network layer protocol, the IP (internet protocol). What ...
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How do bridges divide a larger network into smaller broadcast domains?
I am recently brushing up my computer network knowledge, and came across a seemingly peculiar statement:
A network bridge divides a network into smaller broadcast domains.
As far as I could grasp ...
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Go Back N ARQ Question
I am a computer science under graduation student, and was going through some Go Back N ARQ (Computer Networking) videos on YouTube, and got a doubt in a question, which according to me should have a ...
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0
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Byte Stuffing, escaping a flag at maximum frame
I want to encode a message using byte stuffing where every frame delimited by a flag byte 'F' at both ends and escape code equal to the character E. I am trying to encode the message 'DEEP-FRIED-...
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Throughput in sliding window protocol
Can anyone help me with this test question ? I am not really expert on this.
Assume $1000$BASE-LX network. Communication is using sliding window protocol with $15$ frames, each frame with $1000$ ...
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Difference between centralized computing and distributed computing using Client-Server
I already understand that Distributed Computing is the breakup of having multiple clients rely on a single source, and having each client utilize other clients for information. But my confusion comes ...
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When is an ATM network connection superior to an IP connection?
Currently learning about Networks in Computer Science, and I don't understand why you would ever use an ATM (asynchronous transfer mode) network instead of IP, as IP doesn't have to be as reliable ...
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What is the difference between centralised, decentralised, distributed, fully-distributed?
What is the difference between centralised, decentralised, distributed, fully-distributed, partially-centralised, partially-decentralised system?
Which type or topology is the system attached in the ...
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How Can a Network Server Identify a Specific Computer, Is There a Computer Fingerprint?
Most of websites put some restrictions on how to use their services; the following paragraphs are taken from “Terms of Service” of such website:
Only one account per computer is allowed to view ads. ...
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What exactly would stop me from registering a domain from my own nameserver? [closed]
Can I just make a nameserver and claim away? Are there implemented measures to stop this from happening?
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Resending old frame when a damaged frame has been received in one bit sliding window protocol
I'm reading Tanenbaum's and Wheterall's book on Computer Networks.
I'm trying out some examples of situations that can occur in the one bit sliding window protocol for a datalink layer.
The code for ...
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3
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What is the difference between transmission delay, queuing delay, and processing delay?
My book defines queuing delay as the time the packet waits to be transmitted onto the link. It defines transmission delay as the amount of time required to push all of the packet's bits onto the link. ...
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Difference between 2f+1, 2f and 3f+1
I am currently reading the Practical Byzantine Fault Tolerance paper. I am unable to completely understand the difference between 2f and ...
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How internet speed is manipulated at the physical level
Although I am a computer science major, I am having a hard time understanding how internet providers have control over internet speed (example: offer different speeds to different customers, one with ...
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