Lecture 5 Transmission Dejian Ye Software School Fudan University 15-441 Networking, Spring 2008
1 Lecture 5 Transmission Dejian Ye Software School Fudan University 15-441 Networking, Spring 2008
Physical and Datalink Layers. 3 Lectures 1. Physical layer. Application 2. Datalink layer Presentation introduction, framing, error coding, switched Session networks Transport roadcast-networks Network home networking Datalink Physical 2
2 Physical and Datalink Layers: 3 Lectures 1. Physical layer. 2. Datalink layer introduction, framing, error coding, switched networks. 3. Broadcast-networks, home networking. Application Presentation Session Transport Network Datalink Physical
From Signals to Packets Analog signal “ Digital” Signal Bit stream 00101110001 Packets 0l000l0l0l0l1001010101010ll01l100000011l01010l1l0101010l01010l1010111001 Header/body Header/body Header/body Packet Transmission Sender Receiver 3
3 From Signals to Packets Analog Signal “Digital” Signal Bit Stream 0 0 1 0 1 1 1 0 0 0 1 Packets 0100010101011100101010101011101110000001111010101110101010101101011010111001 Header/Body Header/Body Header/Body Sender Receiver Packet Transmission
Today's Lecture Modulation Bandwidth limitations Frequency spectrum and its use Multiplexing Media: Copper, Fiber, Optical, Wireless Coding Framing
4 Today’s Lecture Modulation. Bandwidth limitations. Frequency spectrum and its use. Multiplexing. Media: Copper, Fiber, Optical, Wireless. Coding. Framing
Why Do We Care? I am not an electrical engineer? Physical layer places constraints on what the hardware network infrastructure can deliver reality check Need to understand impact of the physical layer on the higher protocol layers 》 Fiber fiber copper? > Why do we need wires at all? > Error characteristic and failure modes 》 Effects of distance 5
5 Why Do We Care? I am not an electrical engineer? Physical layer places constraints on what the hardware network infrastructure can deliver = reality check Need to understand impact of the physical layer on the higher protocol layers »Fiber fiber copper? »Why do we need wires at all? »Error characteristic and failure modes »Effects of distance