Network Access Layer It is also called "Link layer It solves the problem of exchanging data between two or more directly connected devices(computers switches routers etc) The link layer packets are usually referred to as frames Point-to-point communications Multiple access communications The services provided by network access layer depend on the specific link-layer protocol that is employed over the link Issues to be addressed Reliability(error detection and error correction) Priority(some data may be more important than others) Addressing(for multiple access) Examples of link layer protocols: Multiple access Point-to-point Protocol(PPP) Ethernet: ieee 802.3 Point-to-point Wireless lan: ieee 802.11 1919 Network Access Layer • It is also called “Link layer”. • It solves the problem of exchanging data between two or more directly connected devices (computers, switches, routers, etc). The link layer packets are usually referred to as frames. — Point-to-point communications — Multiple access communications • The services provided by network access layer depend on the specific link-layer protocol that is employed over the link. • Issues to be addressed: — Reliability (error detection and error correction) — Priority (some data may be more important than others) — Addressing (for multiple access) • Examples of link layer protocols: — Point-to-point Protocol (PPP) — Ethernet: IEEE 802.3 — Wireless LAN: IEEE 802.11 Point-to-point Multiple access