Business data communications 5e by stallings chapter 10

Chapter 10: Ethernet and Fibre Cable Business Data Communications, 5e Increase in High-Speed LANs • Extraordinary growth in speed, power, and storage capacity of PCs • Increasing use of LANs as computing platforms • Examples – Server farms – Workgroups with “power” requirements – High-speed backbones Business Data Commun ications, 5e Increase in High-Speed LANs • Fast Ethernet and Gigabit Ethernet • Fibre Channel • High-speed Wireless LANs Business Data Commun ications, 5e Characteristics of Some High-Speed LANS Business Data Commun ications, 5e Trends Influencing Emergence of High-Speed LANs • Explosive growth of speed and computing power of PCs • Recognition by MIS organizations of the value and importance of networked computing – Centralized server farms – Power workgroups – High-speed local backbone Business Data Commun ications, 5e Traditional Ethernet • Ethernet and CSMA/CD (IEEE 802.3) • Carrier sense multiple access with collision detection • Four step procedure – – – – If medium is idle, transmit If medium is busy, listen until idle and then transmit If collision is detected, cease transmitting After a collision, wait a random amount of time before retransmitting Business Data Commun ications, 5e Ethernet MAC Frame Format • • • • • • • • Preamble: 7-octet pattern of 0s &1s used to establish bit synchronization Start Frame Delimiter (SFD): Indicates actual start of frame Destination Address (DA): Specifies the station(s) for which the frame is intended Source Address (SA): Specifies the station that sent the frame Length: Length of LLC data field in octets LLC Data: Data unit supplied by LLC Pad: Octets added to ensure that the frame is long enough for proper CD operation Frame Check Sequence (FCS): A 32-bit CRC, based on all fields except preamble, SFD, and FCS Business Data Commun ications, 5e Ethernet MAC Frame Business Data Commun ications, 5e 802.3 Medium Notation • Notation format: • e.g 10Base5 provides 10Mbps baseband, up to 500 meters • T and F are used in place of segment length for twisted pair and fiber Business Data Commun ications, 5e 802.3 10BaseX Media Options Business Data Commun ications, 5e 10 Fast Ethernet • Refers to low-cost, Ethernet-compatible LANs operating at 100 Mbps • 802.3 committee defined a number of alternatives to be used with different transmission media Business Data Commun ications, 5e 25 802.3 100Base-T Options Business Data Commun ications, 5e 26 802.3 100BaseX Media Options Business Data Commun ications, 5e 27 Gigabit Ethernet • Retains CSMA/CD protocol and Ethernet format, ensuring smooth upgrade path • Uses optical fiber over short distances • 1-gbps switching hub provides backbone connectivity Business Data Commun ications, 5e 28 Gigabit Ethernet Media Options Business Data Commun ications, 5e 29 10-Gbps Ethernet • Driven by increased network traffic – Increased number of network connections – Increased connection speed of each end-station (e.g., 10 Mbps users moving to 100 Mbps, analog 56k users moving to DSL and cable modems) – Increased deployment of bandwidth-intensive applications such as high-quality video – Increased Web hosting and application hosting traffic Business Data Commun ications, 5e 30 10-Gbps Ethernet vs ATM • No expensive, bandwidth-consuming conversion between Ethernet packets and ATM cells is required • Combination of IP and Ethernet offers quality of service and traffic policing capabilities that approach those provided by ATM • A wide variety of standard optical interfaces have been specified for 10-Gbps Ethernet, optimizing its operation and cost for LAN, MAN, or WAN applications Business Data Commun ications, 5e 31 Physical Layer Options for 10-Gbps Ethernet Business Data Commun ications, 5e 32 Example 100-Mbps Ethernet Backbone Strategy Business Data Commun ications, 5e 33 Fibre Channel • Combine the best features of channel and protocol-based technologies – the simplicity and speed of channel communications – the flexibility and inter-connectivity that characterize protocol-based network communications • More like a traditional circuit-switched or packetswitched network, in contrast to the typical shared-medium LAN Business Data Commun ications, 5e 34 Fibre Channel Goals • Full-duplex links with two fibers per link • Performance from 100 Mbps to 800 Mbps on a single link (200 Mbps to1600 Mbps per link) • Support for distances up to 10 km • Small connectors • High-capacity utilization with distance insensitivity • Greater connectivity than existing multidrop channels • Broad availability (i.e., standard components) • Support for multiple cost/performance levels, from small systems to supercomputers • Ability to carry multiple existing interface command sets for existing channel and network protocols Business Data Commun ications, 5e 35 Fibre Channel Elements • Nodes – The end systems – Includes one or more N_ ports for interconnection • Fabric – Collection of switching elements s between systems – Each element includes multiple F_ ports – Responsible for buffering and for routing frames between source and destination nodes Business Data Commun ications, 5e 36 Fibre Channel Protocol Architecture • FC-0 Physical Media: Includes optical fiber, coaxial cable, and shielded twisted pair, based on distance requirements • FC-1 Transmission Protocol: Defines the signal encoding scheme • FC-2 Framing Protocol: Defines topologies, frame format, flow/error control, and grouping of frames • FC-3 Common Services: Includes multicasting • FC-4 Mapping: Defines the mapping of various channel and network protocols to Fibre Channel Business Data Commun ications, 5e 37 Fibre Channel Media • Media options include shielded twisted pair, video coaxial cable, and optical fiber • Data rates range from 100 Mbps to 3.2 Gbps • Point-to-point link distances range from 33 m to 10 km Business Data Commun ications, 5e 38 Fibre Channel Topologies • Fabric/Switched Topology – includes at least switch to interconnect end systems – may also use multiple switches for a switched network, with switches also supporting end nodes • Point-to-point topology – only two ports, directly connected, with no intervening fabric switches • Arbitrated loop topology – Simple, low-cost topology for connecting up to 126 nodes in a loop – Operates in a manner roughly equivalent to token ring protocols Business Data Commun ications, 5e 39 ... transmission media Business Data Commun ications, 5e 25 802.3 100 Base-T Options Business Data Commun ications, 5e 26 802.3 100 BaseX Media Options Business Data Commun ications, 5e 27 Gigabit Ethernet... provides backbone connectivity Business Data Commun ications, 5e 28 Gigabit Ethernet Media Options Business Data Commun ications, 5e 29 10- Gbps Ethernet • Driven by increased network traffic –... fields except preamble, SFD, and FCS Business Data Commun ications, 5e Ethernet MAC Frame Business Data Commun ications, 5e 802.3 Medium Notation • Notation format: