1.3 The network core
Vložit
- čas přidán 14. 01. 2022
- Video presentation: Computer Networks and the Internet: the network core. Core network functions, packet swtiching, circuit switching, the Internet: a network of networks.
Computer networks class.
Jim Kurose
Textbook reading: Section 1.3, Computer Networking: a Top-Down Approach (8th edition), J.F. Kurose, K.W. Ross, Pearson, 2020.
See gaia.cs.umass.edu/kurose_ross for more open student resources.
What a heart-melting smile.
00:11 The network core operates based on packet switching
02:36 Routing determines the paths taken by packets in a network
04:55 Packets arriving at a router can create a queue if they arrive faster than the router can transmit.
07:11 Packet switching and circuit switching are two different approaches to building a network.
09:36 Circuit switching is inefficient and can only support 10 users at a time
12:00 Packet switching offers statistical multiplexing gain
14:30 The internet is a network of networks.
16:52 The internet is composed of different networks
Crafted by Merlin AI.
Thanks professor for the videos, the books contains very well explanation and well resources for enthusiastic people
Thank you so much for these very interesting lectures!
14:43 🤣 Thank you for great video :)
Understanding the core of network
Very useful lecture.
Thank you!!!
hey, in the book (8th edition) is says that 640,000 bits / 64 kbps = 10 sec. i don't understand why though.. if i convert the bits to kbytes, i get 80 kbytes , and then the division is 80kb/64kbps = 1.25 sec. can you help me understand which one is true and if the book wrong? thank you
1 kb = 1000 bits which means 640,000 bits / 64 kbps = 640,000 bits / 64,000 bps = 10 sec
bps stands for bits per second, not bytes per second.
Bps is the same as bits/sec so when you try to study the expression in terms of dimensions in physics both bit units will be reduced to 1 and the rest is 1/(1/[time]). We are reversing the time twice which results in [time] and after doing the calculations you will get the 10 [time] which is the result you wrote.
Thak very much for these videos, they help me to a lot to get familiar to the concepts of the book.
I have a question from the book 7th edition. On page 30, line 7, there is this calculation: (1.536 Mbps)/24 = 64 kbps. Why the units of this division don't remain Mbps? The result should be 64 Mbps, isn' it? Thanks in advance.
how 35 user? Anyine?
is 35 a fixed value or i can vary
Thats just an example. You may put as much as you want. Just there will be a queue.
Can i ask how did we get the value of 0.0004 please? 😭 At 12:03
(35Cx)*(0.1^x)*(0.9^(35-x))
substitute [11,35] (x>10 active users) into x and add them all up (can't use the sigma notation here sorry) and you get 0.0004 :)
If you have taken probability, you learn about something called a Binomial distribution. Testing each person of the 35 to see how many are actively is like flipping a coin 35 times and seeing how many land heads, instead of it being 50/50, in this case, it's 10/90 for success/failure. Calculating the probability is pretty much how user royeap showed before me, except that you can "simplify" the calculation further, instead of calculating P(X > 10) directly, you can instead calculate P(X > 10) = 1 - P(X
@@royeap3404 can i ask how do u guys learn doing those calculations?
@@abdulrahmannight5910 class 11-12 probability course in my country.
In Excel the formula is: 1-BINOM.DIST(10, 35, 0.1, TRUE)
So in this example we want to know the probability of strictly more than 10 users, when there are 35 trials (e.g. total users), the probability of a user is 10% (i.e. 0.1). The bit on the right actually calculates the probability of between 0-10 users (the true gives the cumulative total up to and including 10), and that amount is deducted from 1 to get the probability of 11+ users.
9/7
07:00 If brits think that they are number one at queueing, just wait until they hear about engineering students at ESOGÜ.
Ah yes, biggest enemy of esogu engineering students, faculty of education bois
- 10 secs
how did u get 35 users plz help