15
votes
Accepted
TCP Connection Termination - FIN, FIN ACK, ACK
A TCP implementation might send a standalone FIN in the first closing segment. However, it can also send a FIN ACK, instead.
The latter is strictly better: the implementation can bundle a "free" ACK ...
- 14.7k
6
votes
Accepted
Could a standardized ternary system be more efficient than the binary system?
Whether this is more efficient depends on the physical properties of the medium, not on any fundamental principle of computer science. And of course there's no reason to limit yourself to ternary ...
D.W.♦
- 166k
5
votes
If the two generals problem is unsolvable how can we human beings agree on things?
Because we don't need guaranteed assurance that something will happen when we have sufficient experience that tells us what is likely to happen. For example, let's say that a friend wants to meet up ...
- 151
5
votes
Accepted
What are the underlying mechanisms allowing us to unsend an email?
The e-mail system has no way of manipulating already sent e-mails, no.
The only services I've seen which allow you to "unsend" an e-mail simply delay the e-mail being sent for a user-determined ...
- 66
5
votes
Accepted
ip/tcp packet decoding without wireshark
My guess is that what you are seeing is a Level 2 Ethernet frame and therefore the preamble is missing. Also the Ethernet checksum seems to be missing. In this case everything seems to line up (the ...
- 29.6k
4
votes
Why are so many internet protocols text-based?
Your question can be interpreted in three ways:
Why is numerical data transmitted in textual representation, as if it had been printed with e.g. printf()?
Why do ...
3
votes
Why are so many internet protocols text-based?
Another reason for this is that textual protocols are easier to interoperate with, and a lot more flexible for the future. Older generations, especially the folks behind Unix, already went through the ...
- 41
3
votes
Looking for two-way communication/consensus/contract algorithm for use in marriage proposal
If you're feeling up for something particularly geeky, you might enjoy a fair exchange protocol, either one based on gradual release (see e.g., this paper) or one based on Bitcoin (e.g., this). The ...
D.W.♦
- 166k
3
votes
Accepted
Serial communication and parity bit
You may find contradictory answers because there are many kinds of serial communication protocols. Some are LSB first, some are MSB first.
For example, for the old RS232 standard and siblings, the ...
- 1,890
3
votes
Compute the union of two sets between two endpoints minimizing communication complexity
You can do this with $O(K \log N)$ bits of communication on average, where $K$ is the size of $|(A\setminus B) \cup (B\setminus A)|$, assuming you are willing to use a non-interactive protocol and are ...
D.W.♦
- 166k
3
votes
Accepted
Is data received after transmission immediately stored and can that be recovered?
Briefly, communication between two hosts/peers on a network occurs by means of network sockets. Roughly a socket is pair (IP,PORT) of numbers which uniquely identifies a host on a network. So, when a ...
- 9,885
3
votes
Accepted
IP Fragmentation
The IP packet has to include the TCP headers in its payload.
Hence we find additional 20 bytes, beyond the 3523 bytes of the sent data (the TCP payload). The total 3543 byes then get fragmented as ...
- 14.7k
3
votes
Basic Question in networking - why max data size of ip datagram 65535 BYTES and not 65535 bits?
16 bits is not the size of the IP datagram; it is the amount of bits required to encode its length. Hence, you can have datagrams of length up to 65536 octets (i.e., bytes), as described in RFC 760:
...
- 5,037
3
votes
Is a "protocol" a set of algorithms and data structures?
is a protocol a pack of algorithms and programming source codes? (in both the computer and network)
No. A protocol is an abstract description of how systems communicate. Source code could be an ...
- 13.4k
2
votes
Accepted
The throughput of the ALOHA protocol if the Binomial distribution was used
I don't think it makes sense to use the binomial distribution.
The point of using the Poisson distribution is that network nodes are assumed to want to transmit with an exponential distribution at ...
- 82.2k
2
votes
Accepted
Link utilization of sliding window protocol
I had the same doubt and was getting nowhere close to grasp the concept. After banging my head for a few days I now think I have understood the basic concept. We define utilization as the total time ...
2
votes
Why is RTS/CTS optional?
Besides RTS and CTS, there are a few other "optional" signals such as DTR, DCD,...
These signals are mostly about checking if the other end of the cable is ready. Ready can mean that the internal ...
- 1,890
2
votes
When packets are not full?
The space isn't used if there isn't data to send. If you're writing a letter, you write as much as you need and you don't insist that the last page must be full of writing. And you don't wait until ...
- 82.2k
2
votes
Accepted
Private IP and public IP
A private IP is not necessarily assigned by an ISP. It is actually a much more general concept: Any node (or cluster of nodes) realizing NAT separates two networks, a public and a private one. Most ...
- 5,037
2
votes
How is the literal meaning of "rendezvous" related to its usage in distributed computing?
In this context, the rendezvous would mean "a bunch of threads meeting together" instead of people. Rendezvous is a method of synchronisation in which at least two threads "meet". In other words, each ...
- 614
2
votes
Accepted
Reaching Shannon capacity of a channel
Your channel is known as the Z-channel. Take a look at Marco Mondelli, S. Hamed Hassani, and Rüdiger Urbanke, How to Achieve the Capacity of Asymmetric Channels.
- 279k
2
votes
Accepted
Is the capacity achieving input of a discrete memoryless channel unique?
I believe the answer is "yes", when $Q$ is square and nonsingular, and "not necessarily", otherwise. See "On the Capacity of a Discrete Channel. I", by Saburo Muroga, Journal of the Physical Society ...
- 278
2
votes
Accepted
tcp congestion avoidance
When we are in AC mode every rtt(round trip time) the congestion window increase by 1(MSS).
Here our current congestion window(cw) is 60 and we know that during transmission round t we get 3 duplicate ...
- 246
2
votes
Accepted
Communication Complexity for Product Distributions
Set disjointness is easier for product distributions since the hard distribution for set disjointness is very far from being a product distribution. What do we require from a hard distribution $(X,Y)$ ...
- 279k
2
votes
Accepted
MAC protocol with throughput of 1
There can be many reasons, but one example would be fairness. Suppose you have a modified version of ALOHA where one priority user has transmission probability set to 1 and all others to 0. Assuming ...
- 288
2
votes
Complexity of two-party maximum
Write $x = (x_h,x_l)$ and $y = (y_h,y_l)$, where $x_h,y_h$ are the high-order parts.
Alice sends $x_h$ to Bob ($n/2$ bits). Bob sends Alice two bits, indicating which of the following holds: $x_h > ...
- 279k
2
votes
Communication protocol so that messages are read "synchronously"
I'm not sure exactly what you're trying to achieve (formulating the goal precisely seems tricky or unclear to me), but you might be interested in reading about "fair exchange" in the ...
D.W.♦
- 166k
2
votes
How can computers tell where the beginning and end of file/packet/frame headers are?
If you click on the link you provided you'll see that the word 802.1Q is itself a link and when you read that page you'll see that the field uses a special value, a magic number if you like for the ...
- 205
2
votes
Two Generals' Problem - Thought Experiment
Let's say $a$ has gotten its second confirmation while $b$ only has one confirmation. $a$ sends an ack to $b$ to tell $b$ it has received the second message. Now, by your rule $a$ should start ...
Only top scored, non community-wiki answers of a minimum length are eligible