29] (20 Marka): choose the correct answer 1. An ATM cell has the payload field of 32 bytes 48 bytes 64 bytes 128 bytes 2- If N is the maximum sequence number, then the window sizes in selective reject and Go-Back-N protocols are respectively: N2, N-1 N, N+1 N+1/2 ,N N-1, N+1 3- Decryption and encryption of data are responsibility of Physical layer Data link layer Presentation layer Session layer 4- High speed Ethernet works on Coaxial cable twisted pair cable optical fiber none of the mentioned 5- What is internet? single network vast collection of different networks interconnection of local area networks 6- In OSI network architecture, the routing is performed by network layer data link layer transport layer session layer 7- Which multiple access technique is used by IEEE 802.11 standard for wireless LAN? CDMA CSMA/CA reservation polling