I-Transmission Control Protocol (TCP) kanye ne- User Datagram Protocol (UDP) yizindlela ezimbili zokuthutha ezijwayelekile ezisetshenziswa nge- intanethi protocol (IP) .
Kokubili i-TDP ne-UDP isebenzisa izinhloko njengengxenye yemininingwane yomyalezo wokupakisha yokudluliselwa kokuxhumana kwenethiwekhi. Izihloko ze-TCP kanye nezihloko ze-UDP ngasinye ziqukethe isethi yemingcele ebizwa ngokuthi amasimu ahlongozwe ngokucaciswa kobuchwepheshe be-protocol.
Ifomethi ye-Header TCP
Isihloko ngasinye se-TCP sinemikhakha eyishumi edingekayo engama- byte angu-20 (ama-160 bits ) ngesayizi. Bangakwazi futhi ukufaka okunye okuyingxenye yedatha engaphezulu kuze kube ngu-40 bytes ngobukhulu.
Lona ukuhlelwa kwezihloko ze-TCP:
- Inombolo yomthombo we-TCP (2 bytes)
- Inombolo yeselula ye-TCP yokuhamba (2 bytes)
- Inombolo yokulandelana (4 bytes)
- Ukuvuma inombolo (4 bytes)
- Idatha ye-TCP ehlehlisiwe (ama-4 bits)
- Idatha egcinwe (ama-3 bits)
- Lawula amafulegi (kufika ku-9 bits)
- Usayizi wefenisha (2 bytes)
- I-TCP checksum (2 bytes)
- I-pointer ephuthumayo (2 bytes)
- Idatha yokuzikhethela ye-TCP (0-40 bytes)
I-TCP ifaka amasimu ezinhlokweni kumsakazo womlayezo ku-oda okubalulwe ngenhla.
- Izinombolo zomsindo we-TCP kanye nendawo okuyiyo yiziphetho zokuxhumana zokuthumela nokuthola amadivaysi.
- Abathumeli bemilayezo basebenzisa izinombolo zokulandelana ukuphawula ukuhleleka kweqembu lemilayezo. Bobabili abathumeli nabamukelayo basebenzisa izinombolo zezinombolo zokuvuma ukuze baxoxe ngezinombolo zokulandelana ezisanda kutholakala noma kulindeleke ukuba zithunyelwe.
- Inkambu yokucasula idatha igcina usayizi ophelele wekhanda le-TCP ngokuphindaphindiwe kwama-bytes amane. Inhloko engeke isebenzise insimu ye-TCP yokuzikhethela ine-offset yedatha ye-5 (emele ama-byte angu-20), kanti inhloko esebenzisa insimu enkulu kakhulu yokuzikhethela ine-offset yedatha ye-15 (emele ama-bytes angu-60).
- Idatha egcinwe ku-header TCP ihlale inenani le-zero. Le nsimu isebenza ngenhloso yokuhlanganisa usayizi wekhanda eliphelele njengenqwaba yama-bytes amane (okubalulekile ekusebenzeni kokucubungula idatha kwedatha).
- I-TCP isebenzisa isethi yezingqimba eziyisithupha ezijwayelekile nezilawulwayo zokulawula (ngamunye ngamunye omelela noma owenzayo ) ukuphatha ukugeleza kwedatha ezimweni ezithile. Enye ifulegi encane, isibonelo, iqala logi lokusetha kabusha ukuxhumeka kwe-TCP. Ukusebenza okuningiliziwe kwalezi zinsimu kudlula ngalesi sihloko.
- Abathumeli be-TCP basebenzisa inamba ebizwa ngokuthi usayizi wewindi ukulawula ukuthi bangakanani idatha abayithumele kumamukeli ngaphambi kokudinga ukuvuma ngokubuyisela. Uma usayizi wesindo luba luncane kakhulu, ukudluliswa kwedatha kwenethiwekhi kuzoba kancane kancane, kanti uma ubukhulu bewindi buba bukhulu kakhulu, isixhumanisi senethiwekhi singagcwaliswa (esingenakusiza nganoma yiziphi ezinye izinhlelo zokusebenza) noma umamukeli angeke akwazi ukucubungula idatha engenayo ngokushesha okwanele (futhi kubangele ukusebenza kancane). Ukuhlelwa kwe-algorithms okufakwe ngaphakathi kwe-protocol kubalwa ngokulinganisa ubukhulu besayizi futhi basebenzise le nsimu yezinhloko ze-TCP ukuxhumanisa izinguquko phakathi kwabathumeli kanye nabamukeli.
- I- checksum value ngaphakathi kwekhanda le-TCP lenzelwa umthumeli wezinkambiso njengendlela yokwenza izibalo ukusiza umamukeli ukuthi athole imilayezo enonakele noma ephazamiseke.
- Insimu ephuthumayo ye-pointer ivame ukufakwa ku-zero futhi inganakwa, kodwa ngokuhambisana neflegi yezokulawula, ingasetshenziswa njengedatha ekhonjiwe ukubeka isigatshana somyalezo njengokudinga ukucubungula kuqala.
- Ukusetshenziswa kwedatha yokuzikhethela ye-TCP kudlula ngaphesheya kwalesi sihloko kodwa kufaka ukusekela ukuvuma okukhethekile kanye newindi yokufaka ama-algorithms.
Ifomethi ye-Header ye-UDP
Ngenxa yokuthi i-UDP inomkhawulo kakhulu kunamandla kune-TCP, izinhloko zayo zincane kakhulu. Inhloko ye-UDP iqukethe ama-bytes angu-8, ihlukaniswe yizinkambu ezine ezilandelayo ezidingekayo:
- Inombolo yeselula yomthombo (2 bytes)
- Inombolo yesibalo sokufika (2 bytes)
- Idatha yedatha (2 bytes)
- UDP checksum (2 bytes)
I-UDP ifaka amasimu ezinhlokweni ekuhambeni komlayezo wayo ku-oda olubalulwe ngenhla.
- Izinombolo zesikhangiso se-UDP kanye nendawo ozoyiyo yiziphetho zokuxhumana zokuthumela nokuthola amadivaysi.
- Inkambu yobude ku-UDP ibonisa ubukhulu bendawo ngayinye ye-datagram kufaka kokubili i-header nedatha. Le nsimu ibanga ngokulinganisa kusuka okungenani ama-bytes angu-8 (ubukhulu besikrini obudingekayo) kumasayizi angaphezu kwama-bytes angu-65,000.
- Ngokufanayo ne-TCP, i- checksum ye- UDP ivumela abamukeli ukuba bahlole imininingwane engenayo nganoma yisiphi isici esonakele somlayezo.