Lectures Top-Down Network Design - Chapter 10: Selecting Technologies and Devices for Campus Networks

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1. Top-Down Network Design, Ch. 10: Selecting Technologies and Devices for Campus Networks Top-DNtkDiDown Network Design Chapter Ten Selecting Technologies and Devices for Campus Networks Copyright 2010 Cisco Press & Priscilla Oppenheimer Selecting Technologies and Devices • We now know what the network will look like. • We also know what capabilities the network will need. • We are now ready to start picking out technologies and devices . • Chapter 10 has guidelines for campus networks. Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 1
2. Top-Down Network Design, Ch. 10: Selecting Technologies and Devices for Campus Networks Campus Network Design Steps • Develop a cabling plant didesign • Select the types of cabling • Select the data-link-layer technologies • Select internetworking devices – Meet with vendors Cabling Plant Design Considerations • Campus and building cabling topologies • The types and lengths of cables between buildings • Within buildings – The location of telecommunications closets and cross- connect rooms – The types and lengths of cables for vertical cabling between floors – The types and lengths of cables for horizontal cabling within floors – The types and lengths of cables for work-area cabling going from telecommunications closets to workstations Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 2
3. Top-Down Network Design, Ch. 10: Selecting Technologies and Devices for Campus Networks Centralized Versus Distributed Cabling Topologies • A centralized cabling scheme terminates most or all of the cable runs in one area of the design environment. A star topology is an example of a centralized system. • A distributed cabling scheme terminates cable runs throughout the design environment. Ring, bus, and tree topologies are examples of distributed systems. Centralized Campus Cabling Building B Building C Building D Cable Bundle Building A Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 3
4. Top-Down Network Design, Ch. 10: Selecting Technologies and Devices for Campus Networks Distributed Campus Cabling Building B Building C Building D Building A Types of Media Used in Campus Networks • CdiCopper media • Optical media • Wireless media Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 4
5. Top-Down Network Design, Ch. 10: Selecting Technologies and Devices for Campus Networks Copper Media Advantages • Conducts electric current well • Does not rust • Can be drawn into thin wires • Easy to shape • Hard to break Copper Media Coaxial Twisted-Pair Shielded Twisted-Pair (STP) Unshielded Twisted-Pair (UTP) Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 5
6. Top-Down Network Design, Ch. 10: Selecting Technologies and Devices for Campus Networks Coaxial Cable • Solid copper conductor, surrounded by: – Flex ible p las tic insu la tion – Braided copper shielding – Outer jacket • Can be run without as many boosts from repeaters, for longer distances between network nodes , than either STP or UTP cable – Nonetheless, it’s no longer widely used Twisted-Pair Cabling • A “twisted pair” consists of two copper conductors twisted together • Each conductor has plastic insulation • Shielded Twisted Pair (STP) – Has metal foil or braided-mesh covering that encases each pair • Unshielded Twisted Pair (UTP) – No metal foil or braided-mesh covering around pairs, so it’s less expensive Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 6
7. Top-Down Network Design, Ch. 10: Selecting Technologies and Devices for Campus Networks UTP Categories • Category 1. Used for voice communication • Category 2. Used for voice and data, up to 4 Mbps • Category 3. Used for data, up to 10 Mbps – Required to have at least 3 twists per foot – Standard cable for most telephone systems – Also used in 10-Mbps Ethernet (10Base-T Ethernet) • Category 4. Used for data, up to 16 Mbps – Must also have at least 3 twists per foot as well as other features • Category 5. Used for data, up to 100 Mbps – Must have 3 twists per inch! • Category 5e. Used in Gigabit Ethernet • Category 6. Used in Gigabit Ethernet and future technologies Optical Media Multimode Fiber (MMF) Single-mode Fiber (SMF) Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 7
8. Top-Down Network Design, Ch. 10: Selecting Technologies and Devices for Campus Networks Copper Vs Fiber-Optic Cabling • Twisted-pair and coax cable transmit network signals in the form of current • Fiber-optic cable transmits network signals in the form of light • Fiber-optic cable is made of glass – Not susceptible to electromagnetic or radio frequency interference – Not as susceptible to attenuation, which means longer cables are possible – Supports very high bandwidth (10 Gbps or greater) – For long distances, fiber costs less than copper Multimode Single-mode • Larger core diameter • Smaller core diameter • Beams of light • Less bouncing bounce off cladding around; single, in multiple ways focused beam of light • Usually uses LED • Usually uses LASER source source • Less expensive • More expensive • Shorter distances • Very long distances Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 8
9. Top-Down Network Design, Ch. 10: Selecting Technologies and Devices for Campus Networks Wireless Media • IEEE 802.11a, b, g, n • Laser •Microwave • Cellular • Satellite Cabling Guidelines • At the access layer use – Copper UTP rated for Category 5 or 5e , unless there is a good reason not to – To future proof the network • Use 5e instead of 5 • Install UTP Category 6 rated cable and terminate the cable with Cat 5 or 5e connectors • Then only the connectors need to be changed to move up in speed – IilIn special cases • Use MMF for bandwidth intensive applications • Or install fiber along with the copper Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 9
10. Top-Down Network Design, Ch. 10: Selecting Technologies and Devices for Campus Networks Cabling Guidelines • At the distribution layer use – MMF if distance allows – SMF otherwise – Unless unusual circumstances occur and cable cannot be run, then use a wireless method – To future proof the network • Run both MMF and SMF LAN Technologies • Half-duplex Ethernet (becoming obsolete) • Full-duplex Ethernet • 10-Mbps Ethernet (becoming obsolete) • 100-Mbps Ethernet • 1000-Mbps (1-Gbps or Gigabit) Ethernet • 10-Gbps Ethernet • Metro Ethernet • Long Range Ethernet (LRE) • Cisco’s EtherChannel Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 10
11. Top-Down Network Design, Ch. 10: Selecting Technologies and Devices for Campus Networks IEEE 802.3 10-Mbps Ethernet 10 Mbps Ethernet 10Base5 10BaseT 10BaseF Thick coax cable 2 pairs 2 multimode 500 meters Category-3 or optical fibers better UTP 10Base2 100 meters 10Broad36 Thin coax cable 3 channels of a 185 meters private CATV system 3600 meters IEEE 802.3 100-Mbps Ethernet 100BaseT 100BaseX 100BaseT4 100BaseT2 4 pairs 2 pairs Category-3 or Category-3 or better UTP better UTP 100 meters 100 meters 100BaseTX 100BaseFX 2 pairs Category-5 or 2 multimode optical fibers better UTP 2000 meters (full duplex) 100 meters Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 11
12. Top-Down Network Design, Ch. 10: Selecting Technologies and Devices for Campus Networks IEEE 802.3 Gigabit Ethernet 1000BaseX 1000BaseSX 1000BaseLX 1000BaseCX 1000BaseT 2 multimode optical fibers 2 multimode or single-mode 2 pairs STP 4 pairs Category-5 UTP using shortwave laser optics optical fibers using longwave 25 meters 100 meters 550 meters laser optics 550 meters multimode, 5000 meters single-mode IEEE 802.3 10-Gbps Ethernet 10GBase with Fiber Cabling 10GBaseLX4 10GBaseSR 10GBaseLR 10GBaseER Multimode or single-mode Multimode optical Single-mode Single-mode optical fibers fibers optical fibers optical fibers 300 meters multimode, 300 meters 10 km 40 km 10 km single-mode Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 12
13. Top-Down Network Design, Ch. 10: Selecting Technologies and Devices for Campus Networks IEEE 802.3 10-Gbps Ethernet 10GBase with Copper Cabling 10GBaseCX4 SFP+ Direct Attach 10GBaseT XAUI 4-lane PCS Twinax UTP or STP 15 meters 10 meters 100 meters Metro Ethernet • Service offered by providers and carriers that traditionally had only classic WAN offerings • The customer can use a standard Ethernet interface to reach a MAN or WAN • The customer can add bandwidth as needed with a simple configuration change Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 13
14. Top-Down Network Design, Ch. 10: Selecting Technologies and Devices for Campus Networks Long-Reach Ethernet • Enables the use of Ethernet over existing, unconditioned, voice -grade copper twisted -pair cabling • Used to connect buildings and rooms within buildings – Rural areas – Old cities where upgrading cabling is impractical – Multi-unit structures such as hotels, apartment complexes, business complexes, and government agencies Cisco’s EtherChannel Data Center Switch 800 Mbps EtherChannel West Fiber Run East Fiber Run 400 Mbps 400 Mbps Wiring Closet Switch Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 14
15. Top-Down Network Design, Ch. 10: Selecting Technologies and Devices for Campus Networks Internetworking Devices for Campus Networks • Switches • Routers • Wireless access points • Wireless bridges Selection Criteria for Internetworking Devices • The number of ports • Processing speed • The amount of memory • Latency when device relays data • Throughput when device relays data • LAN and WAN technologies supported • Media supported Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 15
16. Top-Down Network Design, Ch. 10: Selecting Technologies and Devices for Campus Networks More Selection Criteria for Internetworking Devices •Cost • Ease of configuration and management • MTBF and MTTR • Support for hot-swappable components • Support for redundant power supplies • Quality of technical support, documentation, and training •Etc. Summary • Once the logical design is completed, the physical design can start • A major task during physical design is selecting technologies and devices for campus networks – Media – Data-link layer technology – Internetworking devices • Also, at this point, the logical topology design can be developed further by specifying cabling topologies Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 16
17. Top-Down Network Design, Ch. 10: Selecting Technologies and Devices for Campus Networks Review Questions • What are three fundamental media types used in campus networks? • What selection criteria can you use to select an Ethernet variety for your design customer? • What selection criteria can you use when purchasing internetworking devices for your design customer? • Some people think Metro Ethernet will replace traditional WANs. Do you agree or disagree and why? Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 17