CCNA 1

1. CCNA 1 Module 5: Cabling LANs & WANs

2. Media • The basic functions of media are to carry a flow of information, in the form of bits and bytes, through a LAN. • Networking media are considered Layer 1 (physical layer) components of LANs. The principal medium you will study in this class is called Category 5 unshielded twisted-pair cable(CAT 5 UTP).

3. Network Devices and Symbols--Media • Physical media is Layer 1 in the OSI model, and is the material (or space) where networking signals travel.

4. LAN Physical Layer Implementation • Physical Layer Implementations vary. • Some Implementations support multiple physical media.

5. Ethernet • Ethernet is the most widely used LAN technology, which was used as the basis for the Institute of Electrical and Electronics Engineers (IEEE) 802.3 specification.

6. There are at least 18 varieties of Ethernet, which have been specified, or are in the specification process. Here are some of the most common and important Ethernet technologies.

7. Ethernet Media & Connector Requirements

8. Connection Media • A transceiver is used to convert an AUI to RJ-45, coax, or fiber optic connector

9. TIA/EIA T568A and T568B Standards • For electricity to run between the connector and the jack, the order of the wires must follow EIA/TIA-T568-A or T568-B standards. • If the order of the colored wires is the same at each end, then the cable is straight-through • With crossover, the RJ-45 connectors on both ends show that some of the wires on one side of the cable are crossed to a different pin on the other side of the cable

10. UTP Implementation • EIA/TIA specifies an RJ-45 connector for UTP cable. The letters RJ stand for registered jack, and the number 45 refers to a specific wiring sequence. • The RJ-45 connector is the male component, crimped on the end of the cable. The jack is the female component in a network device, wall outlet, or patch panel

11. UTP Implementation • Use straight-through cables for the following cabling: • Switch to router • Switch to PC or server • Hub to PC or server • Use crossover cables for the following cabling: • Switch to switch • Switch to hub • Hub to hub • Router to router • PC to PC • Router to PC wall outlet, or patch panel

12. Interconnecting Devices using Cables

13. Repeaters • Repeaters amplify and re-time signals, which then enables cables to extend farther to reach longer distances.A typical repeater has just two ports • They are Layer 1 devices • Help solve the problem of too many nodes and/or not enough cable

14. Hub (Multiport Repeater) • Multiport repeaters combine connectivity with the amplifying and re-timing properties of repeaters. • They are Layer 1 devices • They can increase the number of nodes that can be connected to a network. It is typical to see 4, 8, 12, and up to 24, ports on multiport repeaters. • Three types of hub: • Passive Hub as a physical connection point • Active Hub needs power to amplify the incoming signal • Intelligent Hub as active hub but include a microprocessor chip and diagnostic capabilities • Hubs are also called concentrators

15. OSI Layer 1 Devices • All Layer 1 devices, passive and active, create or act on the bits. • They recognize no information patterns in the bits, no addresses, no data, their goal is simply to move bits around. • Layer 1 is fundamental to troubleshooting networks. Problems can be as simple as devices not being plugged in properly!

16. Wireless • Wireless networks use Radio Frequency (RF), laser, infrared (IR), or satellite/microwaves to carry signals from one computer to another without a permanent cable connection. • At the core of wireless communication are devices called transmitters and receivers. The transmitter converts source data to electromagnetic (EM) waves that are passed to the receiver. • Two approaches currently being used to implement spread spectrum for WLAN transmissions are Frequency Hopping Spread Spectrum (FHSS) and Direct Sequence Spread Spectrum (DSSS).

17. Bridges • A bridge connects network segments and must make intelligent decisions about whether to pass signals on to the next segment. • It can improve network performance by eliminating unnecessary traffic and minimizing the chances of collisions. • It divides traffic into segments and filters traffic based on the MAC address. • When a bridge receives a frame on the network, the destination MAC address is looked up in the bridge table to determine whether to filter, flood, or copy the frame onto another segment. • They operate at the Data Link Layer - Layer 2 • They are internetworking devices that can be used to reduce large collision domains.

18. Switches • Switching is a technology that alleviates congestion, in Ethernet, token-ring, and FDDI LANs, by reducing traffic and increasing bandwidth. • Significantly reduce collisions • Connect LAN segments • Switches use a table of MAC addresses to determine the segment on which a datagram needs to be transmitted • They reduce traffic. Switch chooses the port to which the destination device or workstation is connected. • Two basic operations – switching data frames and maintain switching table Advantages over bridges and hubs • Operate at much higher speeds than bridges • Support virtual LANs (VLANs) • Offer greater flexibility in network management

19. Switches • LAN switches are considered multi-port bridges with no collision domain. • Because switching is performed in hardware instead of in software, it is significantly faster. • You can think of each switch port as a micro-bridge; this process is called microsegmentation. • Each switch port acts a separate bridge and gives the full bandwidth of the medium to each host. • Switches reduces collision domains, because each host connection becomes its own collision domain. All hosts connected to the switch are still in the same broadcast domain.

20. ATM Switch FDDI Concentrator 100 Base-T Hub

21. Internetworking Devices • Connect LANs to LANs • Connect LANs to WANs • Connect WANs to other WANs

22. Network Interface Card (NIC) • Its function is to adapt the host device to the network medium. • NICs are considered Layer 2 devices because each individual NIC throughout the world carries a unique coded name, called a Media Access Control (MAC) address. • It provides the host’s access to the medium

23. Peer-to-Peer Network vs Client/Server Network

24. WANs Physical Layer • Serial connections are used to support WAN services. • The speed of these connections ranges from 2400 bits per second (bps) to T1 service at 1.544 megabits per second (Mbps) and E1 service at 2.048 megabits per seconds (Mbps).

25. WAN Serial Connection Options

26. Router • Routers are responsible for routing data packets from source to destination within the LAN, and for providing connectivity to the WAN. • The DTE is the endpoint of the user’s device on the WAN link. The DCE is typically the point where responsibility for delivering data passes into the hands of the service provider.

27. Router and WAN services connection • An NT1 is a device located between router & service provider ISDN switch. NT1 integrated into router has a BRI U interface. • The Cisco 827 ADSL router has one asymmetric digital subscriber line (ADSL) interface. • The Cisco uBR905 router has a coaxial cable, or F-connector, interface that connects directly to the cable system. Coaxial cable and a BNC connector are used to connect the router and cable system.

28. Setting up a Console Connection for Router • The console port allows monitoring and configuration of a Cisco hub, switch, or router. • The cable used between a terminal and a console port is a rollover cable, with RJ-45 connectors.