Data Link Layer Communication at DLL is node-to-node (two end host and the routers as nodes). Links-Cable, air. Two types Broadcast and point-to-point. In broadcast link is shared and in point-to-point the link is dedicated between two ends Services: Located between physical and network layer – When packet is travelling in the internet, DLL of a node(host or router) is responsible for delivering a datagram to the next node in the path. Framing – link addres(dst and src) IP add(src, dst) data, CRC Flow Control Error Control Congestion control Although the TCP/IP reference model is primarily supported as the standard model based on TCP/IP protocol suite, the focus of the TCP/IP reference model does not clearly separate and distinguish