CCNA1: Network Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM CCNA1: Networking Media Copper and Fiber Based Media, Wireless Networking

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Copper-based Media Vocabulary Voltage Electromotive force Resistance Current Attenuation Electromagnetic Interference

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media What Causes Electricity? Electricity is caused when electrons “flow” from one atom to a neighboring atom (current) The electromotive force (what compels the electrons to move) is pressure caused by a separation in charges. This is known as voltage (v) Voltage causes current N N

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Electrical Circuits Electricity flows in closed loops called circuits Every circuit has three components –A source of energy –A conductor (path) for the energy –A load (work the energy is used for) Source Load Conductor -

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Two Types of Circuits Direct Current –Electricity flows in only one direction –Easy to precisely regulate used in computers and networks Alternating Current –Direction of flow changes constantly Continuous wave of variable voltage –Not very precise V V - -

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Resistance For every force in the universe, there is an opposing force The opposite of current is resistance – the opposition to the flow of electrons All materials have some degree of resistance Resistance is measured in ohms (Ω) --- current resistance

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Attenuation In order to overcome resistance, some of the energy of the signal is lost to its surroundings. This is known as attenuation At a certain point, not enough energy is left to overcome any further resistance Attenuation limits the distance a signal can travel over cable --- current resistance -

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Noise All EM signals are subject to outside interference by electromagnetic and radio frequency sources EMI limits signal distances

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Coaxial Media

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Coaxial Pros and Cons Shielding allows signal to travel 500m unrepeated Relatively inexpensive Medium difficulty to install Limited to 10Mbps Relatively unreliable Only usable in bus topologies Not the easiest to install Not the least expensive medium

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Screened Twisted Pair

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Shielded Twisted Pair

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Unshielded Twisted Pair

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media UTP Pros and Cons Inexpensive media Supports speeds up to 1 Gbps Easiest medium to install Most widely used for workstation connections, telephone, etc. Signal can only travel 100m because of no shielding (50m if used for Gigabit Ethernet) Highly susceptible to outside interference

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Fiber Optic Vocabulary Core Cladding Buffer Refraction Laser Laser emitting diode Bend radius Pulling strength

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Laser Safety Laser energy in the infrared or near-infrared range (used in networking) can cause thermal damage to the human eye NEVER look into the end of an optical fiber that is connected to equipment or directly into equipment that generates laser light

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Fiber Optics Two kinds of optical fibers are used: –Multimode – carries multiple frequencies of light. Not very precise, but designed for lower cost LAN use. Fibers may be glass, but typically optical-grade plastic is used. –Single-mode – carries a single light frequency. More expensive, but signals can travel further. Generally used for high-performance networks or long-haul carriers. Almost always glass fibers.

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Fiber Optic Cable

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Common Fiber Connectors

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Fiber Optics Pros & Cons Not subject to EMI, RFI or resistance Theoretically unlimited speed potential Easily adaptable to new technologies Expensive to purchase cable Expensive connectors Most difficult medium to install

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Wireless LANs

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Wireless Networking Increasingly important as computing devices become smaller and more mobile –Laptops –Handhelds –Cell phones Important Concerns –Bandwidth –Security –Interoperability

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Wireless LAN Standards General Standards Number b11 MbpsWEP Security: 64-bit or 128-bit encryption Uses same frequency range as some cordless phones (2.4 Ghz) a54 Mbps Not interoperable with other standards – uses higher frequency range (5 GHz) g54 Mbps Interoperable with b because it uses the same frequency range

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Wireless Network Adapters

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Wireless Access Point (WAP)

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Wireless Access Point WAP

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Wireless Range As range from WAP increases, negotiated speed is reduced to ensure data integrity. Typical Range is feet.

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Authentication & Association Who has access to your network and where? WLAN Authentication occurs at Layer 2 and identifies the DEVICE not the USER Authentication keys must match on the WAP and the Wireless NIC ASSOCIATION means that your wNIC communicates through a particular WAP. This assignment can be changed manually, or automatically as he user moves through the WLAN. Association can also be restricted based on MAC address.

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media WLAN Communications Process Client probes, finds a WAP Client transmits authentication key WAP accepts/rejects key, notifies client of result Client is associated with the WAP All other network processes begin (i.e. dynamic IP address assignment, network login, etc.)

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Two Types of WLANs: Ad-Hoc Ad-hoc system –Also known as an Independent Basic Service Set (IBSS) or Wireless Peer-to-Peer network –All clients communicate directly with one another via their wireless adapters –No WAP is used, and there is no access to a wired network infrastructure

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Two Types of WLANS: Infrastructure Uses a WAP to provide access to a wired network –Technical Term: Basic Service Set (BSS) Multiple WAPs can be used to form microcells with overlapping coverage areas –Technical Term: Extended Service Set (ESS) –Allows the user to roam

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Roaming and WAPs As client moves closer to another WAP, it re- authenticates and re- associates. This process occurs in the background and is transparent to the user.

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media WLAN Roaming Network Admin configures multiple WAPs with overlapping coverage, each one set to a different radio channel When client probes, it chooses a WAP based on signal strength and error rates If signal strength weakens, client will search for another WAP and re-tune to a new frequency, then authenticate and associate with the new WAP

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media What Affects Range? Indoor/Outdoor Use –Building structure (internal) –WAP vs. wireless LAN relay Antenna type –Most consumer wireless products equipped with an Omnidirectional antenna –Other antenna types shape the signal and can extend distance in certain directions

CCNA1: Networking Basics v3.0 CISCO NETWORKING ACADEMY PROGRAM Chapter 3 – Networking Media Antennae Unidirectional- emits signal in one direction only. Omnidirectional- emits signal equally in all directions.