3.2 Transport layer multiplexing and demultiplexing

Video presentation: "Transport layer: Multiplexing and demultiplexing." What are multiplexing and demultiplexing? How is it done? How does it work in TCP and UDP?
Computer networks class.
Jim Kurose
Textbook reading: Section 3.2, 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.

[@stan9912]

Excellent explanation! You should totally write a book about networking.

[@arthurli8587]

He did write a network textbook. You can find the info at the first slide.

[@amirmahdi9993]

@@arthurli8587 Dude I think it was kind of a joke :D

[@maycanro156]

lmao

[@ExZeMIP]

@@arthurli8587 joke went over your head

[@maximus1172]

haha nice one

[@ricp]

man... these explanations are awesome!! so much detail, context, and well organized. Thanks so much for uploading this, sir.

[@ExZeMIP]

ikr!

[@plainfilth1126]

How an someone look so friendly?

[@SeaHorseNSparrow]

A lot of professors and people in academia tend to give off that vibe.

[@LeisureSuitLaurent]

Think its common among teachers that like their job teaching the right course to the right audience.

[@cs513informationsecurity8]

Lovely. The best possible explaination of Ports and Sockets. Thanks.

[@anastasiaoikonomou4347]

You explained this so good!! Thank you, loved the analogy with the car highway made it so much more clearer

[@lukasdalhaug4211]

Very useful video! Thank you for helping me not fail

[@bi_tuxvin4579]

it's 6am, I've got a networking test at 8am, you saved me man

[@user679jk7]

What a nice explanation on this compare to other videos. Thank you!

[@zyada9334]

He is one of the book authors

[@priyeshtandel2101]

Thank you Sir , It is very useful for me.😇

[@florianreyes5808]

I love this man

[@xianchengyin8489]

Thank YOU!

[@basharjirjees8815]

At the end if the port number is 80 for all sockets within the server how can the server distinguish which socket can receive the data?

[@sahilmishra7589]

<a href="#" class="seekto" data-time="763">12:43</a> the source port for ip address C must be same in both process p2 and p3 which is 5775 but in p3 source port is written of port A 9157

[@kralalem2121]

Hello sir, at the end of the video you said for the UDP demultiplexing, only destination port number is required but I think destination ip address is also required for connectionless demultiplexing

[@The_Digamma]

yeah you are absolutely right. In his textbook + slides, it is written correctly. reference slide: chapter - Transport layer, Page 17

[@turkersubasi]

can anyone help me? On UDP protocol how does sender knows the destination port number?

[@jiteshmeghwal2645]

Sir does this mean that multiple processes can share the same tcp port ?

[@abdullahwaris1275]

Yes, as the arriving datagrams can be demultiplexed based on the senders ip and port number as well.

[@JimKurose]

Abdullah is exactly right. On a web server, multiple processes proving web service will share the same TCP port number (80). Jim

[@BipinJethwani]

@@JimKurose I think you should talk about welcoming sockets and the limits on how many such client sockets can be opened on a given machine.

[@beepbeeblebrox3972]

what does the P stand for? program? port?

[@siamhossain8059]

What's the ending music name

[@krishnaas5927]

In the case when UDP is used, If many clients have the same dest port no. say 80 then they would goto the same socket in the destination server right? if so how would the server distinguish between the different packets received as obviously they are from different sources however in UDP only dest port and IP is mentioned, unlike TCP where src port and ip is also included.

[@uditidas]

That's why UDP is connectionless as it only have the destination port to the destination server. It doesn't have other tuples destination ips and port as in TCP to identify it correctly and built a authentic connection.

[@turkersubasi]

does sender choose dest port no arbitrarily?

[@simonl7883]

@@turkersubasi yes

[@Mike-uk2oq]

What happens when 2 distinct processes on a machine accidentally use the same UDP port?

[@sohaibsarosh9839]

Pipelining

[@sohaibsarosh9839]

Pipelining

[@nimittarora8974]

sir SIP lagado

[@klevisimeri607]

🧠

[@karanpreetsingh5966]

I may search for another thousand years but still may not find someone as sweet and loving as you are.

[@Mike-uk2oq]

creep

[@leahzhang3362]

@@Mike-uk2oq It's kinda sweet

[@garvitjain1623]

I may search for another thousand years but still may not find someone as sweet and loving as karanpreet is.

[@gautamsajith5544]

BITS ke bache yaha bhi aagaye