1 / 47

Topic 7: LANs & Backbone Networks - Chapter 15: LAN Systems

Topic 7: LANs & Backbone Networks - Chapter 15: LAN Systems. Business Data Communications, 4e. Ethernet Standards. Ethernet Cable Features 10Base-2 RG-58 coax (thin) 185m, 10Mbps 10Base-5 RG-8 coax (thick) 500m, 10Mbps 10Base-T Cat 3 UTP 100m, 10Mbps

Mercy
Download Presentation

Topic 7: LANs & Backbone Networks - Chapter 15: LAN Systems

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Topic 7: LANs & Backbone Networks- Chapter 15: LAN Systems Business Data Communications, 4e

  2. Ethernet Standards Ethernet Cable Features 10Base-2 RG-58 coax (thin) 185m, 10Mbps 10Base-5 RG-8 coax (thick) 500m, 10Mbps 10Base-T Cat 3 UTP 100m, 10Mbps 100Base-T4 Cat 3 UTP x 4 100m, 100Mbps 100Base-TX Cat 5 UTP/STP 100m, 100Mbps 100Base-FX Fiber optic 100m, 100Mbps Business Data Communications

  3. Types of Ethernet • 10BASE-T (10 Mbps) • Uses a twisted-pair cable with maximum distance of 100 meters • 100BASE-T (100Mbps) • Based on 10Base-T standard, 10 times faster, uses cat-5 UIP/STP cable. NIC is downward compatible to 10Base-T • Gigabit Ethernet • Three new types of Ethernet. They can use Ethernet traditional half-duplex approach, but most are configured to use full-duplex. Also they can run over fiber-optic cables. • 1000Base-T Ethernet, sometimes is called 1 GbE. • 10 GbE • 40 GbE Business Data Communications

  4. 802.3 10BaseX Media Options Business Data Communications

  5. High-Speed LANs • Why? • 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 Communications

  6. 100Base-T Ethernet (IEEE 802.13) • It gives a 100 Mbps data rate using the standard Ethernet bus topology, data link packets and CSMA/CD media access protocol. • Three versions of 100Base-X differing only at the physical layer: • 100BaseTX uses cat 5 UTP • 100BaseFX uses fiber optic cable • 100BaseT4 uses 4 sets of cat 3 UTP (inverse multiplexed) • 100Base-T Ethernet can co-exist with 10Base-T Ethernet. Business Data Communications

  7. Fast Ethernet (100Mbps) • Easy to integrate with existing systems • Can use UTP (-TX) or fiber (-FX) • Uses star-wired topology, using a central multiport repeater (broadcast method) • If NICs support full-duplex mode, switched hub must be used Business Data Communications

  8. 100Base-T Ethernet (IEEE 802.13) Virtually identical to 10Base-T (IEEE 802.3). It gives a 100 Mbps data rate using the standard Ethernet bus topology, data link packets and CSMA/CD media access protocol. Three versions of 100Base-X differing only at the physical layer: • 100BaseTX uses cat 5 UTP • 100BaseFX uses fiber optic cable • 100BaseT4 uses 4 sets of cat 3 UTP (inverse multiplexed) Business Data Communications

  9. 802.3 100Base-T Options Business Data Communications

  10. 802.3 100BaseX Media Options Business Data Communications

  11. Gigabit Ethernet • Still under development • Retains CSMA/CD protocol and Ethernet format, ensuring smooth upgrade path • Uses optical fiber over short distances • 1-Gbps switching hub provides backbone connectivity • May not be good for LAN (explain why) and has been used in backbone networks for point-to-point connections. Business Data Communications

  12. Gigabit Ethernet • 1000BASE-LX: Long-wavelength, supports up to 550m (m-mode fiber) or 5km (single-mode fiber) • 1000BASE-SX: Short-wavelength, supports up to 275 - 550 m(m-mode fiber) • 1000BASE-CX: uses copper jumpers in a single room or equipment rack • 1000BASE-T: uses 4 pairs of Cat-5 UTP Business Data Communications

  13. Gigabit Ethernet Media Options Business Data Communications

  14. Example 100-Mbps Ethernet Backbone Strategy Business Data Communications

  15. 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 packet-switched network, in contrast to the typical shared-medium LAN Business Data Communications

  16. Fiber Channel Network N_port F_port Business Data Communications

  17. Fibre Channel Elements • Nodes • The end systems • Includes one or more N_ ports for interconnection • Fabric • Collection of switching elements between systems • Each element includes multiple F_ ports • Responsible for buffering and for routing frames between source and destination nodes Business Data Communications

  18. 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 Fibre Channel Goals Business Data Communications

  19. *Fibre ChannelProtocol 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 Communications

  20. Fibre Channel - Maximum Distance 800Mbps 400Mbps 200Mbps 100Mbps Single Mode 10,000m 10,000m 10,000m 10,000m M-mode 500m 1,000m 2,000m -- Coaxial Cable 50m 71m 100m 100m STP 28m 46m 57m 80m Business Data Communications

  21. Wireless LANS • LAN extension • Wireless network connected to a main wire-based network • Cross-building interconnect • Point-to-point link between networks in separate buildings • Nomadic access • Wireless link between a LAN hub and a mobile data terminal • Ad hoc networks • a peer-to-peer network (no centralized server) set up temporarily to meet some immediate need. Business Data Communications

  22. Wireless LANs (IEEE802.11) • Wireless LANs are growing very rapidly. Wireless LANs transmit data through the air (space) rather than through wire or cable. • New terms: • WLAN (Wireless LAN) • LAW (Local Area Wireless Network) • IEEE 802.11 standard is likely to be the dominant standard for wireless LAN • It is easy to connect wireless LANs to Ethernet. So, it is usually called wireless Ethernet Business Data Communications

  23. Wireless LANs (IEEE802.11) • Topology. The same as traditional Ethernet. It is both a physical star and a logical bus. • A central wireless access point (AP) is a radio transceiver that plays the role of hub. The maximum range is 100-500 feet depending on interference • Wireless LANs use CSMA/CA (Carrier Sense Media Access with Collision Avoidance) similar to CSMA/CD by Ethernet. Two methods are simultaneously used: • Physical carrier sense method. Packets are sent using stop-and-wait ARQ. Receiver waits less time to send ACK than other computers waiting for available time slots. • Virtual carrier sense method. Using AP hidden node problem must be solved. It is optional. Business Data Communications

  24. Hidden Node Problem • When one computer transmits packets, a computer in another side of AP may not detect the signal and send packets as well. This causes collision at AP. • So, AP is the only device that is able to communicate with both computers. To solve the problem, AP uses controlled access method instead of the contention based method. A computer wanting to send packets must send a request (RTS) to AP. If no other computer is using the circuit, AP will respond with a clear to transmit (CTS) specifying the amount of time for the circuit reserved for the computer. • All other computers hear the CTS and remain silent for the specified time period. Business Data Communications

  25. Types of Wireless Ethernet • IEEE 802.11b. Two basic forms: • Direct-sequence spread-spectrum (DSSS) • Frequency-hopping spread-spectrum (FHSS) • IEEE 802.11a. Expected to run at 5 GHz. Not completely defined yet. • Other type of wireless LANs: • Infrared wireless LAN. Less flexible because most require direct line of sight between transmitters and receivers. • The primary advantage: the reduction of wiring. • The primary disadvantage: the low speed (1-4 Mbps). • Bluetooth. Provide seamless networking of devices in a very small area (up to 30 feet) • Small, cheap • Called Piconet with no more than 8 devices Business Data Communications

  26. IEEE 802.11b • Two basic forms: • Direct-sequence spread-spectrum (DSSS), in 2.4 GHz band. Transmits signals through a wide spectrum of radio frequencies simultaneously. The signal is divided into many different parts and sent on different frequencies. 1, 2, 5.5, 11 Mbps speeds. 20 Mbps version is in the way out. • Frequency-hopping spread-spectrum (FHSS). Uses the same band, but once each frequency in turn. Sender and received synchronize in a frequency. So, minimizes jamming an eavesdropping. 1 Mbps and 2 Mbps. • They are shared media implementation. As the number of devices increases the speed will be reduced. Business Data Communications

  27. Infrared Wireless LANs Business Data Communications

  28. Fiber Distributed Data Interface (FDDI) Fiber Distributed Data Interface (FDDI) is a set of standards originally designed in the late 1980s, but has since made its way into backbone networks. FDDI is a token-passing ring network that operates at 100 Mbps over two-counter-rotating fiber optic cable rings. Business Data Communications

  29. Topology The FDDI standard assumes a maximum of 1000 stations and a 200-kilometers (120 miles) path that requires a repeater every 2-kilometers. The second ring is for backup. Single attachment stations (SAS) and dual-attachment stations (DAS) are both computer that can connect to one or both of the rings, respectively. If the cable in the FDDI ring is broken, the ring can still operate in a limited fashion. Business Data Communications

  30. Topology Business Data Communications

  31. Topology Business Data Communications

  32. Media Access Control The FDDI-MAC scheme uses a variation of the IEEE 802.5 token-passing standard. • Messages and the token are sent in different frames separately in a FDDI LAN. A computer can send data only when it captures the token. • When a computer on an FDDI network waiting for transmission receives the token, it holds the token and then transmits all messages that were attached to it. The computer then transmits whatever messages its wants before transmitting the token. • When receiver receives the data frame it simply copy the data frame leaving it to be absorbed by the sender. Business Data Communications

  33. Backbone Network Architecture LAN LAN LAN LAN LAN LAN Distribution Layer Access Layer Core Layer Figure 7-5 Backbone network design layers (FD) Business Data Communications

  34. *Backbone Network Architectures • Routed backbone – using routers • Advantage – clearly segment each part of the network • Disadvantage – Delay, and more management • Bridged backbone – using bridges, not popular any more • Advantages – cheaper, simpler • Disadvantages – difficulties in management • Collapsed backbone –using switches, is most commonly used. • Advantages - Better performance, Fewer network devices are used • Disadvantages – switch problem may fail whole network, more cabling work • Two types • Rack-based collapsed backbone • Chassis-based collapsed backbone • Virtual LAN (VLAN) Business Data Communications

  35. Client Computer Client Computer 10/100 Ethernet Client Computer Router to WAN Layer-2 Switch Client Computer 1GbE on fiber Client Computer 1000Base-T Client Computer Layer-3 Switch 10/100 Ethernet Router to Internet Client Computer 1GbE on fiber 1GbE on fiber Client Computer 10/100 Ethernet Client Computer Layer-2 Switch Client Computer Server Server Client Computer 1000Base-T Server Server Client Computer Figure 7-11 Central Parking’s collapsed backbone (FD) Business Data Communications

  36. *Virtual LAN (VLAN) • A new type of LAN backbone network architecture by intelligent high-speed switches. VLAN is configured using software not hardware. • Single-switch VLAN – VLAN inside a switch • Multiswitch VLAN – VLAN using several switches. • VLAN is normally faster than traditional LANs, and provide better opportunity to manage data flows Business Data Communications

  37. VLAN switch Client Computer VLAN switch VLAN switch Client Computer 10/100 Ethernet Client Computer VLAN switch VLAN switch Client Computer 1GbE on fiber Client Computer 1000Base-T Client Computer VLAN switch 1GbE on fiber VLAN switch VLAN switch VLAN switch 1GbE on fiber VLAN switch VLAN switch VLAN switch 1GbE on fiber VLAN switch VLAN switch VLAN switch VLAN switch VLAN switch Figure 7-14 IONA VLAN network (FD) Business Data Communications

  38. How is a packet transmitted through the Internet? • An IP address tells the destination • Transmission is done one hop after another actually at data link layer • This is just like you bought a flight ticket from Lubbock to New York. The ticket package indicates New York is your destination (IP address). However, you may have three coupons for three flights that connect your route via two more cities between: Dallas and Chicago. Each coupon indicates your arriving airport (destination data link layer address), e.g. DFW, CHI and JFK. Business Data Communications

  39. A TCP/IP Example Business Data Communications

  40. How TCP/IP Works • How a client access a web server in the same subnet with a known address? • How a client access a web server in a different subnet with a known address? • How a client access a web server in the same subnet with an unknown address? Business Data Communications

  41. *NetBIOS vs. NetBEUI • NetBIOS has 18 commands for PC connections. • NetBEUI adds 8 more and is used as a transport protocol. It is faster and more efficient than NetBIOS • When NetBEUI is in use, NETBIOS becomes API that invokes NetBeui. • They can support a LAN with less than 200 PCs. Business Data Communications

  42. *Windows Network Model Windows Network Model Internet Model Layer 7 I/O Named Pipes Mail Server Application layer: FTP, TELNET, HTTP, etc. Environment Subsystem Layer 6 Provider Interface Layer 5 NetBIOS (Redirector) Transport layer: TCP, UDP Layer 4 TDI WINSOCK NetBEUI TCP/IP Layer 3 Network layer: IP NDIS 3.0 NDIS Environment and Drivers Layer 2 Layer 1 Data link layer Physical layer 802.2 802.3 802.4 802.5 Business Data Communications NDIS: Network Driver Interface Specification

  43. *NDIS • NDIS (Network Driver Interface Specification) is a Windows specification for how communication protocol programs (such as TCP/IP) and network device drivers should communicate with each other. Business Data Communications

  44. *NetBIOS NetBIOS (Network Basic Input/Output System) • Created by IBM for its early PC Network, was adopted by Microsoft, and has since become a de facto industry standard. • A program that allows applications on different computers to communicate within a local area network (LAN). • Used in Ethernet, token ring, and Windows NT networks. Business Data Communications

  45. *NetBEUI NetBEUI (NetBIOS Extended User Interface) • Developed by IBM for its LAN Manager product and has been adopted by Microsoft for its Windows NT, LAN Manager, and Windows for Workgroups products. • A new, extended version of NetBIOS, the program that lets computers communicate within a local area network. • Formalizes the frame format (or arrangement of information in a data transmission) that was not specified as part of NetBIOS. Business Data Communications

  46. *NetBIOS over TCP/IP • NetBIOS over TCP/IP runs over the TCP/IP, so that you can share drives and printers over the Internet. • In the "Network" configuration window in Windows 95, there is no option for NetBIOS over TCP/IP, but a "NetBEUI" entry, with which Microsoft actually means NetBIOS over NetBEUI. • With the installation of TCP/IP protocol, Windows automatically installs the "NetBIOS over TCP/IP”. • If you do want the TCP/IP protocol, but not "NetBIOS over TCP/IP" (because of security problem), you should uncheck "Files and Printer Sharing" in the Bindings tab of the TCP/IP entry in Network Configuration. Business Data Communications

  47. Data transmission using TCP/IP and Ethernet Ethernet packet header IP packet TCP packet HTTP packet User Data Ethernet packet trailer IP address Data link layer address Business Data Communications

More Related