Osi pog’onasi, vazifalari, asosiy protokollar

3-sath:

Ulanishsiz tarmoq xizmati (CLNS) - ITU-T Rec. X.213 [ISO / IEC 8348] . SCCP X.213-ga asoslangan. Ulanishsiz tarmoq protokoli (CLNP) - ITU-T Rec. X.233 [ISO / IEC 8473- 1] . Ulanish-yo'naltirilgan tarmoq xizmati (CONS) - ITU-T Rec. X.213 [ISO / IEC 8348] . Ulanish-yo'naltirilgan tarmoq protokoli ( X.25 ) - ITU-T Rec. X.233 [ISO / IEC 8878] . Bu X.25 protokolidan CONSni ta'minlash uchun foydalanish.

4-sath:

• 4-sath:

Ulanish rejimida va ulanmasdan rejimda transport xizmatlari ITU-T Rec tomonidan belgilanadi . X.214 [ISO / IEC 8072] ; ulanish rejimi xizmatini ta'minlovchi protokol ITU-T Rec tomonidan belgilanadi . X.224 [ISO / IEC 8073] va ulanishsiz rejimda xizmat ko'rsatishni ta'minlovchi protokoli ITUT Recr tomonidan belgilanadi . X.234 [ISO / IEC 8602] .