Binit Mohanty Ketan Rajawat Networks Binit Mohanty Ketan Rajawat
Recap – Layered Architecture Application layer for GUI Transport layer for Reliability Networking layer for routing MAC layer for Media access control Physical layer for modulation
Ethernet Used in IITK LAN One medium - many users IP address and Names - the DNS server CSMA/CD – Carrier Sense Multiple Access with Collision Detection
Internetworking Eg: Connecting many LANs Each Network has Routers Routers run some programs for finding the best path Data in form of packets appended with source and destination address Forwarded according to routing table
TCP – Transport Layer Limitations of PHY layer Solution : TCP Packets are lost, reordered, duplicated Congestion, overflow Solution : TCP Reliability by ACKs Numbering of packets Limit transfer rate according to congestion
TCP : Connection Establishment Called a connection oriented protocol as opposed to a best effort protocol
TCP : Slow Start
TCP : Close Connection
TCP When would one not want TCP ? When would reliability be at a lower priority ? Streaming Data – streaming video Energy efficiency – Sensor Networks
GSM – Global System for Mobile
GSM – channels Channels comprising of frequencies and time slots Broadcast channel – network identity, frequency of operation Control Channels –signal power, channel estimate, timing estimate, call origination Traffic channels for voice