Cyclic Redundancy Check(CRC) example

[@shobhanarender6910]

My prof took an hour to explain this, and you did the job in less than 10 minutes- and better. Thank you!

[@neilharrison01]

Hi, my name is Neil Harrison and way back in the 1980s I was an engineer working for BT. I created the CRC4 frame/mult structure for the 2.048Mbit/s transmission system that became a CCITT standard in G.704/706. Did all the modelling work on a BBC Micro. Seems a long time ago now. Amazed how it lasted. Been retired as a engineer for about 9 years.

[@DaBestAround]

Hi Neil, I presume you are in the UK (because you mentioned British Telecom!). I am a Computer Science student who currently learning Computer Networking and I'm afraid I don't understand what CRC 4 is but I would genuinely love to know more. If you have the time, I would really appreciate if you could provide more insight. Cheers,

[@neilharrison01]

@@DaBestAround CRC4 - this is a cyclic redundancy code of degree 4 (polynomial is X^4 + X + 1) that I used to detect errors in the 2Mbit/s transmission systems and also to prevent timeslots from mimicking the frame alignment signal (FAS) and thus stop incorrect frame alignment. If you really want to know more see CCITT Rec G.704/G.706....and/or do a search on CRC4. A long time ago for me.....amazed anyone still has interest in this work I did back then.

[@DaBestAround]

@@neilharrison01 Hey Neil, Thanks for the response. I looked into it and I tried to find your name somewhere throughout the documents but I couldn't find it. I totally believe you mate - everything you've said has been bang on and I don't know why anyone would even lie about that 😆 There is still a bit of interest in CRC4. See, I clicked on this video to learn about CRC (for my upcoming networking exam) If you don't mind me asking, how did you even get into the field - I know things were different back then but I'm genuinely curious. Also, even if it is a bit tedious, how did you end up creating the frame structure? - was it assigned as a task to you by BT or did you just do it? Cheers.

[@neilharrison01]

@@DaBestAround I graduated with a 1st class Hons BSc in Electrical/Electronic Engineering in 1981. My final year project was creating a pulse width modulated microwave radio link....so I was heavily into Maxwell's equations and stuff like that. I took a job with BT in Nov 1981....originally I wanted to do microwave research at Martlesham but optical fibres had just hit the news so there was not much call for microwave engineer research. So I ended up working in London at BT HQ. My first boss asked me to look at what was happening with the US 1.5M transmission standards as they were using a CRC6 polynomial to detect errors and prevent false framing. Our 2M transmission structure was better than the 1.5M system (for many reasons) but I only had room in bit 1 of timeslot zero to create a frame/mult structure and so I was restricted in the size of CRC I could use....ergo why it is CRC4 and not of higher degree (higher degree = better error burst detection). However, CRC4 is perfectly OK for what I designed it to do. After getting the CCITT standards G.703/704/706 sorted, that define the physical and frame/mult stuff, in Geneva in mid/late 1980s, I spent many years afterwards researching what real error distributions on digital metallic/optical/radio systems looked like....they for sure are not Poisson-like (as was the case on the old analogue transmission systems), but follow complex self-similar burst characteristics (weather is a key cause, and weather is bursty/self-similar). I spent the next few years working as the UK expert at CCITT meetings defining standards for error distributions detection and stuff related to that area. Later got promoted to more senior management roles and stopped doing hands on real engineering....hated this stuff, but it was well paid. Hope that background helps.

[@neilharrison01]

Did this not suffice? CCITT Recs don't mention author's names. You can find my name listed amongst IETF stuff related to OAM. But they are old now. Quite a few patents listed against my name wrt OAM topics in protocols like MPLS.

[@aparnasanthosh5093]

Can hear ur frnd telling "Change pen! Change pen!" 😂😂

[@shoorveer7250]

Kuch padai bhi kr lo 😁

[@Q8Duelist]

lol

[@vanceelwood6894]

You provided the first explanation that I actually understood. I can do it now! Thanks :)

[@Zumerjud]

What you said at 4:42 was incorrect. You are trying to find the bits to append to the word that will serve as the CRC check. The remainder is exactly those bits. You will append them to the original word and this is sent to the receiver. The receiver then divides the received bits by the same divisor and the remainder should be zero. Other than that, good video :)

[@federicocastro757]

+Zumerjud but it was clear anyway

[@rastogimitanshi]

+1

[@BlindMidget]

Was it you calling to tell him he said something wrong?

[@riteshsuvarna8345]

yes u r right

[@dahamne]

yes you are right

[@srhalnon]

First video on this topic ive found with an indian guy whose accent i can actually understand! awesome!

[@arishem1014]

@@snowzley2389 lolz

[@vkv7968]

You are awesome. Congrats. Also you understanding his accent has nothing to do with his knowledge or awesomeness too! 😉

[@NiceGuyShaders]

I'm here cuz I was curious how file integrity check works. I think I'm dividing more than I really needed and I love it. Thank you

[@akritomandal]

sir, you are a man, who teach me the process absolutely correct. Thanks "The BootStrappers".

[@442jetmech]

8 YEARS GOIN8 years going and still helpful, thanks man

[@Shigization]

Thank you for helping this Kiwi student catch up after being sick!

[@TheBootStrappers]

+Shigeruken Thank you, feels really good to be able to help someone :)

[@FerrisMcLaren]

I watched a lot of videos trying to figure out how this works...yours made the most sense, so thanks

[@adityaarora2443]

Change Pen :P..nice video ! :D

[@021_sufiahsrimuliawatyn.l2]

Thank you bro,bravo!! You're smart,i've been trying to find a video about crc and this vid is the only one can make me get it!!

[@omonofua]

Thanks brother, this really helped me understand the assignment I was given...Am a master on CRC now. most grateful

[@kekw5357]

love to you my brother from india, took less than 10 minutes to explain this concept

[@Hustlers_hab]

thank you man you just saved my mid term result

[@adarshtrivedi6876]

Bhai peeche wala banda gazab hai.........And the video, it's superb

[@ajaynwa9783]

Lol

[@prasanna.chinmalli6865]

Good explanation, explained In simple and understandable way , thank u ❤

[@gouthamnagraj5445]

your clarity on the topic is awesome!!!!!!!!!!!!!!!!

[@rishabhjha9869]

Your voice is so nice. I mean it is soothing to hear and also clearly audible. Thank You for this tutorial.

[@_GayatriKulkarni]

Thank you so much it's now easy to understand crc coding because of you....😊

[@matthewcliff5540]

my dad was explaining CRC and your video helped out a lot

[@baalawk3748]

better than my teacher :s

[@TheBootStrappers]

+mundrey topey Thanks :)

[@NiceGuyShaders]

Always has been

[@kajalkoravi7960]

the only example I understood is yours. Thank you. keep uploading video!

[@seemakanswal8602]

thank you man tomorrow was my paper and this video helps me lot :D

[@ChaseEdson]

you’re an absolute legend

[@sandramukuka]

Nice video. I had issues doing the division, I got it wrong each time and my lecturer made me feel dull instead of explaining where I was not getting it (typical of China lol)... Now I see where i was confusing the whole thing lol. Thanks a lot.

[@leonaheidern]

I just had a Singaporean lecturer try to teach me that is the same race as the person who did this video. He was going way too fast on the power point for me to understand. It's not the race it's the explanation. I am Chinese too by the way , sometimes these academics go way too fast and probably taught too many classes of the same thing that they don't realise every student is different

[@leonaheidern]

I don't understand the lecturer either that's why I am looking on KZbin. this person explained what I not understanding why the answer was a certain way. I sux at formulas and math concepts

[@WhoMightThis1Be]

you have a similar accent as my professor, that makes me feel better about this =D

[@SurafelMiheret]

Thanks bro... u helped me a lot .. those CRC things was my worst nightmare

[@adithiyagurupatham3255]

Really a nice video and please do continue to upload a lots of video in the future

[@amitkr1683]

thanks, friend, now I understand completely.

[@imtriggeryt6582]

thank you very much brother you explained it so easily hats offf to you.

[@abhisekdatta2012]

really it helps me to learn the CRC at the exam time. thank u.

[@TheBootStrappers]

+abhisek datta Thank you :)

[@khushibhoj]

you guys are just awesome, killed it in the least time

[@scpah]

Thanks bro..u solved my problem..I was unable to understand how d subtraction was taking place..now I got it.

[@vasantjoseph]

Thank you for the simple easy to understand explanation

[@jeneshjayasheel3911]

Beauty ! the concept of amending zeros was my question and that's been cleared now. Thanks legend

[@TheBootStrappers]

Thank you :)

[@poornimaa2246]

By watchg once..... I understd...tqsm 😀😀😀

[@羅辰瑋]

Thanks for kindly share this. Now I understand how CRC works. Very helpful video.

[@sparshyadav49]

Thanks for the explaination , it was really easy as you explained Video still useful after 6-7 years 🧮🧮

[@AJ-fo3hp]

Very useful basic simple crystal clear Thank you

[@NFG_WOLFGANG]

Your teaching was perfect and really nice.. I could follow up and understand everything thanks for this video

[@sanket7877]

Thanks bhai for this example , I have my exam in 4 days .

[@erukullavineeth3702]

Really to good and i just understood within the half of the explaintion.👏👏👏👏👏👏👏👏

[@ranguvamshikrishna7563]

Thanks for helping explaintion is very nice 👌👌👌👌😉

[@vmunguti]

This video was very helpful actually it made me understand CRC with ease. Great Job

[@theseasonaldigest]

Thank you :) This video helped me to understand CRC at last!!

[@sangitabhagat3695]

Thank you I have an exam tomorrow and it helped me good work

[@AtaurRahman-jt8bd]

thanks man tomorrow is my exam and u helped me a lot

[@enginsama]

FINALLY A GOOOOD TUTORIAL. THANKS BRO

[@sweetprincessbloom1]

Really nice video... helping me pass my exam...!! Thnx a lot..!!

[@임주영-e6o]

thank u a lot i was not aware of the CRC ,However because of u , i got it now kkk

[@manishadas7434]

tomorrow is my exam and u saved me ..thanks a lot

[@veerannagarisahithireddy7096]

Grt explanation and thanks for the video

[@sanskrutikurale4802]

thank you to make my concept clear

[@shivakumar-zb8ii]

Thanx sir for such a clean explaination

[@shivamt949]

Awesome brother .......... Thanks for this tutorial......Have a awesome days ahead 👍👍👍👍

[@Unknown-rz5hj]

Helped a lot. Good work

[@anushkasingh8053]

Thank you so much for explaining the concept in such an easy way👏👏👏

[@shivammaniya2962]

Oh brother such an wonderful work.

[@chvishnu619]

I've got an exam tomorrow on this. Thank you!

[@PawanKumarYouTube]

Thanks.. It was quick and easy for me to understand. Appreciate ur effort..

[@elliotimanpour343]

Very helpful video keep up the good work.

[@TheBootStrappers]

Thanks a ton :)

[@bhagyalekshmis1588]

this video helped a lot thank you

[@purnabhisheksripathi5398]

Bro i understood.very good explanation.

[@careerpk2904]

i got help after watching this video,thank you :)

[@pritamchatterjee6388]

thanks man...very easy way to understand :)

[@TheBootStrappers]

+pritam chatterjee Thank you :)

[@marufabdullahrionMaruf]

Great Tutorial. It's really helpful for me and hope everybody will get help from this video.

[@TheBootStrappers]

+Maruf Abdullah Thank you :)

[@Rohitnair14]

Thanks a lot bhai! Saved my ass just before the exam! :D

[@TheBootStrappers]

+Rohit Nair Thank you :)

[@PooperBelt]

You are better than my teacher

[@atharvakango7244]

NICE explanation ..!!..Informative !

[@chiragahir1459]

Thanks brother

[@najun8162]

GOD BLESS YOU! U are a saviour❤️♥️

[@Nora-lh3zs]

4 years later. thank u :3

[@lmanjunath6930]

Very good Work.Keep it up.

[@kaviraj8082]

Was very useful at the last minute revision.... Thanks bro

[@rvlabaji]

Thank you very ,very help full for me..........!

[@adityaraut5966]

keep continuing the good work! much appreciated...

[@AnkuGarg]

Thanq so much....very good explain :)

[@praveenkumarnaidu3475]

Thankx bro...u made all my confusions clear now...keep posting...keep rocking 😀

[@abcc764]

It's was so helpful..nice video.👌

[@shyammuchulapuri3198]

Nyc bro❤👌

[@amirnazari6427]

It was helpful, thank you!

[@OgllyBoogly]

Thanks for the clear video.

[@vineeshabezavada3244]

Tysm..... Helped a lot! 😊

[@bilamaha]

Thank you, it helps a lot

[@KenilDhanani]

Thanks bro m goona pass my exam coz of ur help hahaha xd thank ya\ :")

[@khanghoang3289]

thank you so much for this lecture

[@DiaryofAhsan]

Very useful

[@Egitam-ow7ih]

good explanation , cleared all my doubts

[@fatima_1117]

Thank u soo much🤗👍👍 explanation was simple and easy to understand 👏 well done

[@Anita82011]

Thanks a lot really helped me in my exam....:)

[@TheBootStrappers]

+Anitha Manoharan Thank you :)

[@mrdynamiko]

Thank you for your wonderful explanation.

[@kamisettyprathyusha9436]

woowww simple and clear explanationnn

[@nancydrew2969]

it was really helpful buddy. thanks alot :)

[@akhileshyadav1280]

awesome teaching bhai ❤

[@girishmintu3152]

I wish I'd a sir like you

[@_KolambkarDnyandevHanumant]

Kdkkk bhai tujya mule udya 4mark bhetle exam mdhey 🫂

[@mr.g.n.r.]

😂😂💥

[@anujashelar9841]

Ur video really helped ✌🏻

[@sreejithnair3901]

Thank u man.... It helped alot.....

[@TheBootStrappers]

+Sreejith Nair Thank you :)