Questions tagged [tcp]

For questions about Transmission Control Protocol (TCP), a transport protocol used to encapsulate data across a network for reliable communication.

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Application Layer [closed]

I have this pseudocode down here in the picture? I think this is an UDP connection because it doesn't have listen and accept in the while loop!. And i think this is the Client do i have got it ...
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How does a device get a response from a HTTP request without an open port on the router?

I don't know much about how TCP/IP works, so please bear with me here. I was wondering how, when your computer makes an HTTP request from a random port(on that device) to port 80 on a server, it gets ...
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1answer
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How to use the TCP traceroute in Juniper?

How to use the TCP traceroute in Juniper? In Juniper OS I only know traceroute ip_address I don't know how to traceroute a destination with TCP protocol. is it possible to implement it?
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How to find the client's application port during communication [closed]

After reading firewall rules about inbound and outbount I have some questions and the most sources focus on the server's ports. What happens to the client side when is trying to make a connection to ...
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What would it require by a server and a connection to have 10000 TCP clients connected to a server pumping out 20k bytes per second? [closed]

Not sure if its the right place here but i am abit lost in trying to imagine what machinery is needed and network needed the following and dont really know what params to calculate upon : A server ( ...
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1answer
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IPv4 and UDP/TCP packets inside of ICMP packet?

A week ago, after opening wireshark, i was surprised by seing a storm of ICMP packets from different IP addresses. While deep analysing of thoses packets, i noticed that those ICMP packets contains ...
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1answer
38 views

how data are fragmented based on MTU and MSS?

just to be clear.. if a sender wants to send a data of 1800bytes ( assuming MTU be 1500bytes so MSS = 1500-40 (taking min ip and tcp header) = 1460bytes) Then there will be three segments 750 + 750 + ...
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28 views

RFC 6298 application

I got this? How many Fragments that are going to be sent are: 10800 / 1200 = 9 segments to Host B. And the full time is: (9*1200) / 1600000 = 6.75 ms According to RFC 6298 [1]: (2.2) When the first ...
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Congestion control in transport and network layers in TCP/IP

Why do we need congestion control in BOTH the transport layer and network layer in TCP/IP model. Cant we be good enough with control in just one of the layers only? And how do they differ?
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What flow control mechanism does ethernet uses?

Datalink layer is basically responsible for 3 major functions - Error detection/correction - CRC is used by ethernet Collision detection - CSMA/CD is used by ethernet But I couldn't find what flow ...
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What if receiver changes its IP address during the transmission process?

Suppose I am sending data to a laptop with IP address say x but before data could reach its destination the laptop is moved to another network and now its IP address becomes Y. Will the receiver still ...
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1answer
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Suspect MTR showing incorrect packet loss through router; other tools are not showing loss

Using MTR (sending TCP with or without SYN), I'm consistently seeing packet loss on one intermediate router in the path. UDP does the same. I'm use TCP to avoid the ICMP packet flood limits set. I ...
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1answer
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Propogation delay vs time required to send out a complete frame on channel

I was reading Data Communications and Networking by Behrouz A. Forouzan in which for simple Aloha protocol the vulnerable time given was T(fr) (time required to send out a complete frame on the ...
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2answers
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What will happen if a server receives a duplicate SYN for an existing connection?

If a server receives a fresh SYN packet for a connection that is already established, what should it do? I have already seen What will happen at server side if it received 2 SYN packet from the same ...
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4answers
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TCP Handshake fails on Cisco ASA

I am using a Traffic Generator for setting up a TCP connection that should pass a Cisco ASA firewall. My topology looks like this: +------------------+ ...
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what's the window size of TCP pipelined sending

We know that instead of send a packet and wait a RTT then send another(stop and wait), TCP use pipelined sending as picture below shows: so my question is, what's the maximum packets can be send in ...
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1answer
51 views

Which of TCP flags will use a timer, and what Timer will use?

When I study the TCP protocol life cycle, There are 3 stages: Establish Connection Data Transmission Connection Removal TCP have 6 Flag types: SYN, ACK, PSH, FIN, RST, URG. TCP has 4 Timer: ...
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what does PSH flag in TCP header do when the receiver is not reading data?

we know that when TCP data is received with PSH set, it will immediately transfer the received data to the application.and let's when pushed data arrives the receiver side and the receiver application ...
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1answer
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How do I properly serialize a network packet [closed]

So I'm currently writing a program that is essentially just a server and a client. The idea is that I want them to be able to communicate with one and other by sending packets back and forth. And I'm ...
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1answer
36 views

TCP Congestion Control, Sender window = minimum ( Congestion window, Receiver window)

When can the congestion window size be greater than the receiver window size? An example of a scenario will be helpful. I know that the congestion window is used by the sender to gauge the network ...
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no length header to indicate the data size of a TCP segement? [duplicate]

I was reading a textbook on UDP/TCP segment structure as picture below shows: And the author says: an explicit length value is needed since the size of the data field may differ from one UDP segment ...
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1answer
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what's the acknowledgement number after retransmitting the missing segment [duplicate]

I was reading a textbook which describes TCP fast tetransmit, below is a picture If the TCP sender receives three duplicate ACKs for the same data, it takes this as an indication that the segment ...
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2answers
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Estimating the Round-Trip Time in TCP

I was reading a textbook which says: Let’s begin our study of TCP timer management by considering how TCP estimates the round-trip time between sender and receiver. This is accomplished as follows. ...
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why double TimeoutInterval to avoid a premature timeout occurring for a subsequent segment that will soon be acknowledged?

I was reading a textbook which describes how TCP managing the retransmission timeout interval as: TimeoutInterval = EstimatedRTT + 4 *DevRTT An initial TimeoutInterval value of 1 second is recommended....
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Confused with packet reordering

I was reading a textbook which says about TCP protocol "Selective Repeat": We have assumed that packets cannot be reordered within the channel between the sender and receiver. This is ...
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20 views

Sequence number in acknowledgement

Let's say there are two host A and B, and host A sends data to host B and host B only sends ack segement(I know TCP is full-duplex but in this scenario, only A sends data to B, B only sends ack to A). ...
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Can anyone explain to me the difference between the PSH and URG flags in TCP segment?

According to me when PSH flag is set, it indicates that data will have to be sent immediately to the wire and on receiving side the data has to be pushed to the application immediately. When URG flag ...
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How to find which protocol is used by lower layers? [duplicate]

When we type https://stackoverflow.com/ all the data which is sent to this server would be using HTTPS protocol in transport level So is it possible for me to know which error detection, flow control ...
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no way of knowing whether or not the receiver has correctly received the last piece of transmitted data when checksum is corrupted? [closed]

I was reading a text book which shows a simple reliable data transfer service that is similiar to TCP: And the author said: Protocol rdt2.0 may look as if it works but, unfortunately, it has a fatal ...
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How does UDP control the flow of data in file transferring?

I know that transferring files over UDP is possible even though TCP is preferred. My question is how does the server know how much the client can handle or vice versa, or any router in between. TCP ...
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1answer
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Sequence numbers and wrap around concept

I was reading an article about the topic and I came across this :"During connection establishment each party uses a Random number generator to create initial sequence number (ISN), which is ...
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3answers
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How is tcp/ip implemented

Well, first of all I am new to networking. And I have studied the layered structure of tcp/ip protocol stack. I know that the layered structure is an abstract model, but I didn't know how the ...
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When the first bit reaches the host B, which bit is exit from the host A?

When the first bit reaches the host B, which bit is exit from the host A?
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Connecting to device which requires specific IP [closed]

[Disclaimer: I'm a complete networking novice, and this question might not even be well suited for this site. I welcome pointers to other stack exchanges if appropriate.] I'm trying to connect a ...
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1answer
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Do both sides need to agree on MSS value?

By definition, The TCP Maximum Segment Size (MSS) is the maximum amount of data that a host is willing to accept in a single TCP/IPv4 datagram. And MSS is one of the parameters which is negotiated ...
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Why does DHCP use UDP and not TCP?

DHCP uses UDP as its transport protocol. DHCP messages that a client sends to a server are sent to well-known port 67 (UDP—Bootstrap Protocol and DHCP). DHCP Messages  that a server sends to a client ...
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TCP/IP conditions to end an etabilished connection

What happens if the Client crashes and never closes the connection? Or the server crashes before being able to send a ACK FIN packet. Are those cases implemented in software?
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Can the network devices run out of ephemeral ports due to high use of websockets?

This might be a really stupid question, but something I really want to understand. My understanding is a tcp connections staying open indicates that each of the network devices between the client and ...
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3answers
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End-to-End delay

I’m working through questions from computer networking top down approach and was hoping to get some clarity on the end-to-end delay calculation. At this stage we are not considering processing, ...
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1answer
50 views

Is it valid to send consecutive tcp packets having overlapping data?

Assuming: TCP Window Size of client: 2000 bytes MSS (maximum segment size) of client: 1500 bytes Now server want to send 3000 bytes to client B1..B3000. Server sends: Packet-1: Contains B1..B1500 ...
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what is the definition of out degree and in degree in computer networks?

in wikipedia we have a good definition for in degree and out degree in a graph: " The degree of a node is the number of connections or edges the node has to other nodes. in-degree is the number of ...
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What steps must be accomplished in each layer of the TCP/IP model to connect a website?

What steps must be accomplished in each layer of the TCP/IP model to connect a website?
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1answer
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how to send a number of TCP packets and capture only those packets using tshark?

I'm using iperf3 to send 1005 TCP packets with the commands: iperf3 -s -i 1 -f m -p 5200 -D iperf3 -c 10.60.0.113 -k 1005 -bitrate 0 --reverse --omit 2 -p 5200 In server, client respectively. The ...
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Why does FTP passive mode use a range of ephemeral ports as opposed to a single well known port? [closed]

In FTP passive mode, I read that the server sends a random port number to the client where it can establish a data channel. Then client establishes a data channel from its random port number to this ...
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2answers
29 views

multicast udp streaming dst and src address assignment

If I am streaming on a host using the internet outside my nat, how is multcast addressing work with respect to streaming for example, if the application outside sends to 224.0.0.1 how is the packet ...
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3answers
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Maximum packet size Ethernet Frame and IP packet

I am a little bit confused about one fact. According to the specification, the ethernet frame maximum size is 1518 bytes, and the IPv4 packet size Length field in an IPv4 header can be up to 65535 ...
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TCP Handshaking Meaning of RST

I am trying to implement TCP handshaking but receive RST instead of ACK: No. Time Source Destination Protocol Length Info 62 24.622012890 192.168.0.147 ...
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4answers
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Is multicast possible in tcp?

I got an assignment to implement unicast, multicast and broadcast in UDP or TCP in java, so I searched for it and I only got UDP implementation of multicast. My question is following: Is there ...
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Is TCP's MSL value equivalent to IP's TTL value?

Definition of MSL according to RFC 793: Maximum Segment Lifetime, the time a TCP segment can exist in the internetwork system. Arbitrarily defined to be 2 minutes. Definition of TTL according to ...
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TCP and Go-Back-N

While studying about TCP i notice that is very similar to Go-Back-N, but ,i think i'm missing something very important: In http://www.ccs-labs.org/teaching/rn/animations/gbn_sr/ we can see that in ...

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