The tag has no wiki summary.

learn more… | top users | synonyms

4
votes
0answers
34 views

Byzantine generals problem with signed messages (Lamport)

I have some trouble understanding Lamport's paper about the Byzantine generals problem when it comes to signed messages. He showed that, with signed messages, the number of generals must be at least ...
0
votes
2answers
34 views

Probability of Success in Slotted Medium Access

Suppose you have a network which uses time division multiplexing (i.e. Slotted Aloha). There are $N$ nodes each transmitting in a given slot with probability $p$. I understand that the probability a ...
1
vote
1answer
18 views

Aggregate Rate and Poisson Process in Aloha

I'm having a hard time understanding what is mean't by the aggregrate rate $\lambda$ and what it means for throughput in unslotted and slotted Aloha protocols. The more I seem to read about poission ...
0
votes
1answer
42 views

Layered Structures

I'm trying to check how general and valid protocol suite system ( layered structure ) are. Does anyone know if radio communication ( broadcast ) via AM or FM , for instance can be viewed in the light ...
1
vote
1answer
47 views

What's the point of Subnet Masks?

I'm having trouble understanding the point of Subnet Masks. I was reading a nice article on Tech-FAQ on the topic, but it has left me a bit confused. When I first heard about Subnets, it was ...
3
votes
2answers
149 views

Why is the throughput (performance) of the Slotted Aloha protocol β‰ˆ 0.36

I've read that the throughput - that is, the amount of good useful messages relative to capacity - of the Slotted ALOHA protocol for communication networks is roughly 0.36%. But its not clear how we ...
2
votes
1answer
117 views

Why is the throughput (performance) of the Aloha protocol β‰ˆ 0.18?

I've read in a few places (like here that the throughput - that is, the amount of good useful messages relative to capacity - of the ALOHA protocol for networks is roughly 0.18%. But its not clear ...
1
vote
1answer
65 views

Three phase commit : study case

Consider a group of five processors implementing three-phase commit protocol. During the execution of the protocol, the coordinator and one other process crash. Two of the remaining processes are ...
1
vote
1answer
45 views

Why does packet data don't need trailer/footer while frame needs it?

Why does packet don't need trailer/footer while frame needs it? I am trying to understand networking concept regarding OSI & TCP/IP layering. I have googled a bit and it says that the footer in ...
3
votes
0answers
527 views

totally ordered multicast with Lamport timestamp

I'm studying Distributed Systems and synchronization and I didn't catch this solution of totally ordered multicast with Lamport timestamps. I read that it doesn't need ack to deliver a message to the ...
0
votes
0answers
39 views

Picking an optimal initial congestion window size (high bw, high latency and short bursts)?

What is a known strategy to approach a situation where short bursts of data are being sent very often over a high bandwidth, high latency cable? I am aware of cubic but even that does not utilize a ...
1
vote
2answers
383 views

How does DNS work if there is no recursive querying?

Suppose I type in the website www.youtube.com. The computer first asks a local domain name server (DNS) what the IP address of this website is. If it can't find ...
0
votes
1answer
6k views

Performance differences between Go-Back-N and Selective Repeat ARQ protocols?

This is what I know: GBN weakness is the fact that when the window size is too large, the number of packets in the pipeline grows and one packet error causes the retransmition of many packets ...
0
votes
1answer
422 views

Jamming signal useless in CSMA / CD?

I'm looking at collision detection in communication protocols, in particular Carrier sense multiple access with collision detection (CSMA/CD). According to what I've read on Wikipedia, a collision ...
4
votes
3answers
257 views

Why is it seemingly easier to resume torrent downloads than browser downloads?

I really wonder how torrent downloads can be resumed at later point of time. If such a technology exists, then why is it not possible in browsers? It is often not possible to pause a browser download ...
3
votes
1answer
44 views

Block detection in repeated stream

I need to recover a data block from a repeated stream of data. I'm looking to see what algorithms may already exist for this as it does not feel like a novel situation. Here are the specifics: ...