Unit of Learning # 2 The Physical Layer Sergio Guíñez Molinos sguinez@utalca.cl 2-2009
Local Area Network (LAN) Redes de Computadores 2
Historic topologies more used in LAN Ethernet Logical Bus and Physical Start Token Ring Logical Ring and Physical Start FDDI Logical Ring and Physical Double Ring Redes de Computadores 3
Nowadays topologies LAN Fast Ethernet Giga Ethernet Fiber Channel Wireless LAN Redes de Computadores 4
Main characteristics Fast LAN Fast Ethernet Giga Ethernet Bit rate 100 Mbps. 1 Gbps., 10 Gbps. Fiber Channel 100 Mbps. 3,2 Gbps. Wireless LAN 1 Mbps. 54 Mbps. Transmission Medium UTP, STP, Fiber Optic UTP -STP, Fiber Optic UTP,Coaxia l, Shield Cable, Fiber Optic Microondas a 2,4 GHz, 5 GHz Access CSMA/CD CSMA/CD Conmutado CSMA/ Sondeo Standard Support IEEE 802.3 IEEE 802.3 Fiber Channel Association IEEE 802.11 Redes de Computadores 5
Classic Ethernet Xerox 10 Mbps (Ethernet) Bus Topology. Access Protocol CSMA/CD. Problems? Transmission and reception (MAC) Access Protocol Redes de Computadores 6
Classic Ethernet #2 Frame Redes de Computadores 7
Access Protocol CSMA/CD Carrier Sense and Multiple Access with Collision Detection) 1. If medium is free to transmit 2. Else, listen until that medium is free 3. If detect collision in the transmission, stop transmission 4. Wait a random time, then try to transmit again Binary exponential delay After i collisions, a random number of slot times between 0 and 2^i 1 is chosen. Redes de Computadores 8
Access Protocol CSMA/CD #2 Redes de Computadores 9
Access Protocol CSMA/CD #3 Collisions Frame Length ( Tf ) Spreading Delay between nodes (Sd ) Tf > 2*Sd Redes de Computadores 10
Frame Ethernet IEEE 802.3 Redes de Computadores 11
Frame Ethernet IEEE 802.3 Frame formats. IEEE 802.3. Redes de Computadores 12
Frame Ethernet IEEE 802.3 #2 Preamble 7 bytes with the following pattern: 10101010 SDF (Start Frame Delimiter) Bits sequence 10101011. DA (Destination Address) Hardware Address SA (Source Address) Hardware Address Redes de Computadores 13
Frame Ethernet IEEE 802.3 #3 Length Data 1518 Bytes. Min. 64 Bytes. required to CSMA Max 1500 Bytes. FCS (Frame Check Sequence) 32 bits to CRC
Hardware Address Ethernet Address of 48 bits Address Ethernet is a hardware address Broadcasting Multicasting Redes de Computadores 15
Ethernet Cabling Redes de Computadores 16
Ethernet Cabling IEEE 802.3 <Rate Transmission in Mbps> <method signaling> <length in Mts.> Original bit rate Ethernet 10 Mbps For instance: 10Base5 10Base-T Redes de Computadores 17
Ethernet Cabling #1 The most common kinds of Ethernet cabling. Redes de Computadores 18
Ethernet Cabling #2 Three kinds of Ethernet cabling. (a) 10Base5, (b) 10Base2, (c) 10Base-T. Redes de Computadores 19
Ethernet Cabling #3 Cable topologies. (a) Linear, (b) Spine, (c) Tree, (d) Segmented. Redes de Computadores 20
Ethernet Cabling #4 (a) Binary encoding, (b) Manchester encoding, (c) Differential Manchester encoding. Redes de Computadores 21
HUB vs SWITCH Redes de Computadores 22
HUB vs SWITCH Redes de Computadores 23
HUB vs SWITCH #2 Redes de Computadores 24
Switch Layer 2 Store and Forward Switch Store the frame and make routing to destination. Cut Through Switch Read the MAC and and routing to destination as soon as possible, when detect destination address. Redes de Computadores 25
Switch Layer 2 #2 Problems??? Broadcast Storm Multiple ways Discussion... Redes de Computadores 26
Switch Layer 3 A lot PCs and WS. 10-100 Mbps Switch Layer 2 Kernel of the Network Switch Layer 3 100 Mps-1Gbps Redes de Computadores 27
Fast Ethernet Redes de Computadores 28
Fast Ethernet IEEE 802.3 100Base-T Options Redes de Computadores 29
Fast Ethernet #2 100BaseT 100Mbps STP,UTP,FIBER 100Base-FX Fiber Optics Full-Duplex 200 Mbps? Is necessary Switch layer 2 o 3? Is necessary CSMA/CD? Redes de Computadores 30
Fast Ethernet #3 Redes de Computadores 31
Giga Ethernet Ethernet 10 Gbps. Redes de Computadores 32
Giga Ethernet Redes de Computadores 33
Giga Ethernet #2 Options physical medium Giga Ethernet Redes de Computadores 34
10 Gbps Ethernet Options physical medium 10 Giga Ethernet Redes de Computadores 35
10 Gbps Ethernet #2 No expensive, bandwidth consuming conversion between Ethernet packets and ATM cells. Network is Ethernet, end to end. IP plus Ethernet offers QoS and traffic. policing capabilities approach that of ATM Wide variety of standard optical interfaces for 10 Gbps Ethernet. Redes de Computadores 36
Fibre Channel Redes de Computadores 37
Fibre Channel 2 methods of communication with processor: I/O channel Network communications Fibre channel combines both Simplicity and speed of channel communications Flexibility and interconnectivity of network communications Redes de Computadores 38
Fibre Channel #2 Structure End-terminal Redes de Computadores 39
Architecture of Fiber Channel Protocol Layer Architecture Physical Layer Transmission Protocol FC-1 Frame Protocol FC-2 Collaborative Services FC-3 Transformation FC-4 Physical Medium and Topology
Fibre Channel #3 Five Applications of Fibre Channel Redes de Computadores 41
Wireless LAN Redes de Computadores 42
Wireless LAN IEEE 802.11 Services Association Reassociation Disassociation Authentication Privacy Redes de Computadores 43
Wireless LAN # 2 IEEE 802.11 Architecture Redes de Computadores 44
MAC Redes de Computadores 46
MAC Deterministic and non-deterministic Ej: Redes de Computadores 47
References W. Stallings, Redes en Internet de alta velocidad. Rendimiento y calidad de servicio, Segunda Edición,Prentice-Hall, 2004. A. Tanenbaum, Redes de Computadores, Cuarta Edición, Prentice-Hall.2003. Douglas Comer, Redes Globales de Información con Internet. TCP/IP. Principios básicos, protocolos y Redes de Computadores 48
Unit of Learning # 2 The Physical Layer Sergio Guíñez Molinos sguinez@utalca.cl 2-2009 Redes de Computadores 49