Questions tagged [layer4]
For questions about OSI Layer 4 (transport layer).
180 questions
0
votes
1
answer
102
views
Layer 4 window size
In the TCP three-way handshake stage Sender and receiver window sizes are advertised.
But what if the window size advertised by the receiver is 1000 bytes, but the sender has about 2000 bytes of data?
- 139
10
votes
5
answers
2k
views
Do all TCP packets from same http request take same route? If not, how can I better understand where each went?
I understand TCP has a max size for each packet. This limit is probably easily reached with data-heavy responses.
Therefore do all these packets follow the same route (image of a train) or are they ...
- 203
0
votes
1
answer
112
views
Double-syncs in a TCP communication
One of my co-workers had some odd output on some Wireshark logs with "connecting twice". I went and looked, and sure enough it looks like the client redoing the opening TCP handshake ...
- 103
0
votes
1
answer
145
views
Understanding how the Acknowedge number is subsequently used by a TCP client
I understand the Acknowledgement number (from e.g a server perspective) represents the sequence number plus the received number of bytes, plus one (suggesting the next byte number it expects from the ...
- 11
0
votes
1
answer
113
views
Would TCP cubic congestion control always cause packet loss as it tries to increase window size until packet drop?
Setup:
Sender talking to receiver through a ToR where all interfaces are 100 Gbps but the ToR has a smart flow limiter that drops packets if the throughput for a flow is above 10 Gbps.
Traffic:
Sender ...
- 155
6
votes
1
answer
530
views
MTU and MSS concept
A client and a server are separated by a router.
I don't understand the principle of MSS adjustment.
When the client sends a SYN packet to the server, the SYN/ack server replies with its MSS.
Example: ...
- 61
6
votes
2
answers
1k
views
Why is MSS important? Why can't we just rely on the MTU?
Note: I understand both what MTU and MSS do so I am not asking about their function here. I understand that when a TCP connection is being established, the MSS is exchanged and it dictates the maximum ...
- 1,031
2
votes
1
answer
111
views
TCP Header Data Field
In TCP header there was a field called a data field which stores data, but does this field store the IPv4 header + datagram or just the datagram?
- 139
0
votes
1
answer
551
views
What are different encoding schemes used in gigabit ethernet?
I was reading about digital transmission, there are many steps namely:
Analog to Digital conversion
Source coding
Channel coding
Line coding
Pulse shaping
Modulation
Multiple access techniques
...
- 103
2
votes
2
answers
412
views
BGP and Multi-Hop Adjacencies Using TCP
I am studying the basics of BGP and my book states the following:
"BGP sessions use TCP port 179. TCP allows for adjacencies that are multiple hops away"
I understand that this allows ...
- 1,031
0
votes
1
answer
212
views
Why do we need L7 reverse proxy for increasing the limit of max TCP connection to the backend?
I stumbled upon a YT video which explains that there's technically no limit to the number of connections that can be opened between the clients and servers even if there's a reverse proxy between them....
- 143
3
votes
2
answers
3k
views
How is TCP Segmentation/Reassembly Identified?
There might be something simple that I'm missing, but I just can't understand how related TCP segments are identified.
So let's say I want to send 2000 bytes using TCP with an MSS of 1500 bytes. I ...
- 33
1
vote
2
answers
699
views
Differences between TCP congestion and TCP flow control
From my understanding, flow control essentially how much the receiver can process.
Suppose I can send packets at 100mb/s but the receiver can only process information at 10mb/s, flow control would ...
- 13
0
votes
1
answer
122
views
HTTP and TCP relationship
I always wondered how HTTP knows when it has enough TCP segments in order to process a request or response.
Can someone give me more information about the process?
Thanks.
- 117
0
votes
2
answers
1k
views
UDP supports multicasting and broadcasting in transport layer or application layer?
We know that UDP does supports multicasting and broadcasting. My question is which layer "UDP supports multicasting and broadcasting"? Is it transport layer or application layer? We know ...
- 425