Chapter 4 Intro to Routing & Switching

 Upon completion of this chapter, you should be able to:  Describe the purpose of the physical layer  Identify characteristics of copper cabling  Make a UTP cable  Describe fiber optic cabling & its advantages  Describe wireless media  Select the appropriate media to connect devices  Describe the data link layer, its purpose & structure of a frame  Compare logical & physical topologies  Describe media access control

 What does the data link layer do to help send data?  What does the physical layer do to help send the data?  What does the physical layer do to help receive data?  What does the data link layer do to help receive data?

4.1.1

 Connect wired or wirelessly  Switch, WAP, or ISR

 How do you connect to a wired network?  NIC  How do you connect to a wireless network?  WLAN NIC  What are disadvantages of wireless?  Distance from WAP (can use extender)  Sharing of wireless signal (more=slower)

4.1.2

 Copper  Electrical pulses  Fiber  Light  Wireless  Radio waves  All follow standards so they can communicate together  ISO (RJ-45), EIA/TIA (568B), IEEE (802.3, ), and others

 Identify network devices & cabling

4.1.3

 Physical components  Cabling, NICs, connectors, ports/interfaces  Encoding  Pattern of voltage for 1’s & 0’s Differentiates data from control bit info The patterns indicate start & end of frame  Signaling  It’s what represents a 0 or 1/like Morse code  Volts/no volts; short pulse of light/long; type of radio wave  Random timing between signals (Asynchronous) or set time (clock) between signals (synchronous)

 Speed/capacity a media can handle  Like size of a hose  Bigger hose= more water through it

 Measure of transfer of bits over a time  Varies on amount & type of traffic, latency (delay)  Can only be as fast as the slowest link

 The measure of usable data transferred over a given period of time.  Throughput - traffic overhead  Example: Ethernet is 100Mbps Throughput is 85Mbps If traffic overhead is 15Mbps, then goodput is 70Mbps

 What’s the difference?  Type of copper cabling  Bandwidth it can handle  Type of connectors used  Wiring order & colors  Max distance

 GCIT’s Ethernet is 1000Mbps. It’s throughput is 800Mbps. If overhead is 10Mbps, what is the goodput?  790Mbps  Why are encoding methods (patterns for the bits) used by the physical layer?  So the code can be recognized  Distinguishes data from control bits  Tells where frame starts and ends  An asynchronous signal means what?  No clock signal sent

 Morse code & the timing between the bits is known as what?  Signaling  The speed or capacity of your media is what?  Bandwidth  The actual amount of bits/data that can actually pass over a period of time is what?  Throughput  The more bandwidth you have, the more __________________ you should have.  Throughput

4.2.1

 Inexpensive & easy to install  Look up a box of Cat 5e 500ft spool  Electrical pulses  Distance limit (attenuation)  Interference from EMI/RFI, crosstalk  To avoid problems, select the right cable for the right situation

 UTP, STP, Coaxial

 Most common  RJ-45 connectors  8 wires, 4 twisted pairs  Twisting prevents crosstalk  Color coded

 Better EMI/RFI protection  More expensive to buy & install  RJ-45  8 wires, 4 twisted pair wrapped in foil

 Used in very early Ethernet & now for TV  Wireless antenna connections  Cable Internet  Shielding  Thicker cable  BNC or F-connector

 Flammable  Electrical hazard; attracts lightning

 What in the ceiling could “mess up” the electrical signal in an UTP cable?  Lights, electrical boxes/equipment  Radio waves cause what kind of interference?  RFI  An electrical motor near a UTP cable causes what kind of interference?  EMI  Signals from one cable jump into another. What problem is this?  Crosstalk

 Excessively long cable runs cause what problem?  Attenuation, signal gets weaker  What is the solution to prevent crosstalk?  Twisting of the pairs  Which cables have shielding?  STP & coaxial  What kind of connector is on UTP & STP?  RJ45

4.2.1

 What does the twisting do?  No shielding so it relies on cancellation  Wires are paired for this & twisted a certain distance apart  RJ45 connector

 Cat 3, 5/5e, 6  Based on bandwidth rates

 Straight-through  We’re going to make them  Crossover  We’re going to make them  Rollover (Cisco’s)  Connect to console port  568B to reverse

 TIA/EIA 568A & 568B

 568B to 568B  Connect unlike devices  Computer to Hub/Switch  Switch to router port  On the PC NIC  Pins 1 & 2 transmit  Pins 3 & 6 receive

 Straight-through  568B to 568B  White-Orange  Orange  White-Green  Blue  White-Blue  Green  White-Brown  Brown

 568A to 568B  Like Devices  Switch/hub port to switch/hub port  Router port to router port  PC to router port  PC to PC

 Crossover  568B to 568A  Change Oranges & Greens on ONE SIDE!  White-Green  Green  White-Orange  Blue  White-Blue  Orange  White-Brown  Brown

 What is the 568B color order?  Wor/Or, WGr/Bl, WBl/Gr, WBr/Br  For speeds of 1000Mbps or more, what Category cable should be used?  Cat 6  What cable…  Goes between same devices? Crossover  Goes from PC to switch? Straight through  Goes from serial to console port? Rollover

 What colors do you change for a crossover cable?  Oranges & greens  What pairs transmit?  1 & 2  What pairs receive?  3 & 6

4.2.3

 Transmits pulses of light  Laser or LED  Used for long distance  Glass or plastic  No EMI/RFI; no lightning attraction  High speed  LAN backbone  Connect ISP to Internet  2 fibers cables used  Transmit & receive

 Multimode  LED  Many paths of light  Used in LANs/Campuses 2000 meters  Less $, used more  Single Mode  Laser light  Single path of light  Connects backbone/NOCs 3000 meters  More $, faster speed

IssueUTPFiber Optic Bandwidth Distance Immunity to EMI/RFI Immunity to Electrical Hazards Media/Connector cost Installation Skill/Cost Safety Precautions

 Which cable is more expensive, copper or fiber?  Fiber  Which cable allows data to travel further, copper or fiber?  Fiber  Why are two strands of fiber used for communication?  Light can only travel in one direction at a time. This will allow for full-duplex.

 What signal travel on a single-mode cable?  Laser  Which cable would be used to go further distances?  Single mode  Why would you use fiber between buildings rather than copper?  Fiber does not attract lightning

4.2.4

 Many devices use wireless  Cordless Phones 2.4GHz Interference  Microwave Ovens Interference  Range  Solid Walls a problem  Not as fast as, or reliable as, wired  Security  Wireless is east to access & can be intercepted Authentication & Encryption now used

 Specifies data speed, range, RF spectrum  IEEE standards, Wi-Fi  a, b, g and n  Wi-Fi Alliance tests devices from manufacturer  Will work with other devices w/ same logo

 1999  2.4GHz  11Mbps  150ft range indoors  300 ft range outdoors

 1999  5GHz  Unused at that time  Less congestion  54Mbps (faster than B)  NOT compatible with b/g/n  75ft-150ft range  Originally too expensive  Now hard to find

 2003  2.4GHz  54Mbps  150ft range indoors  300 ft range outdoors  Compatible with b

 2.4Ghz  Mbps  Up to 750ft range  Backwards compatible b/g

 Access Point (AP)  Connects wireless devices to wired network  Wireless NIC adapter  Gives wireless to a host

Standard Maximum Speed Frequency Backwards compatible a b g n ac

Standard Maximum Speed Frequency Backwards compatible a 54 Mbps5 GHzNo b 11 Mbps2.4 GHzNo g 54 Mbps2.4 GHz802.11b n 600 Mbps2.4 GHz or 5 GHz802.11b/g ac 1.3 Gbps (1300 Mbps) 2.4 GHz and 5.5 GHz802.11b/g/n ad 7 Gbps (7000 Mbps) 2.4 GHz, 5 GHz and 60 GHz b/g/n/ac

 Maybe???  Doesn’t really show wireless

 You’d like to add wireless with speeds up to 1.3Gbps. Which spec should you buy?  ac  What is the max speed of G?  54Mbps  What connects wireless devices to a wired network?  AP  What wireless spec is no compatible with others?  a

 What could interfere with a wireless signal?  Cordless phones, microwaves, solid walls  What are 2 other concerns with wireless networks?  Security and distance  b, g, and n all operate on what frequency?  2.4GHz

4.3.1

 TCP/IP equivalent?  Data link layer jobs:  Takes layer 3 packets & encapsulates into frames  Controls access to the media/encapsulates for the media being used  MAC addressing

 LLC  Closer to layer 3  Identifies what layer 3 protocol is being used  MAC  Closer to layer 1; rules for accessing media  MAC address  Ready for convert to any type of bits/media

 Encapsulates data into a frame  Adds frame header & trailer  Signifies beginning and end of packet

 What layer of the OSI generates the electrical signals?  Physical layer  What layer decides the best path?  Network layer  What layer handles the encapsulation for the proper media going to be used?  Data link layer  What are the 2 sublayers of the Data Link layer?  LLC & MAC

 What signifies the beginning & end of a frame?  Header & trailer  Which sublayer identifies the network protocol being used?  LLC

4.4.1

 Rules of the rode way  Depends on:  Topology  Media sharing Point-to-point WAN connection (between 2 routers) Shared connection (LAN)

 Full duplex  Half duplex

 Either all complete for the line or take turns  This is MAC (Media Access Control) at Layer 2  CSMA/CD (ETHERNET)  Listen for silence, transmit  Collision= all backoff random time, listen for silence, retransmit  CSMA/CA (WIRELESS)  Listen for silence, notify all you are sending, gets clearance to send, transmits  Token Passing (OLD for Token Ring/FDDI)  Wait for your turn/have the token  Logical ring topology

 Ethernet’s collision detection system is known as what?  CSMA/CD  Describe CSMA/CD.  wireless networks use what for avoiding collisions?  CSMA/CA  What is the main difference between CSMA/CA & CD?  CA notifies all that you are sending

4.4.4

 How is the FCS helpful in a frame?  Determines if there are errors  What is in the frame header?  Start frame & MAC addresses  The data in a frame can be how many bytes?  bytes

 Complete the study guide handout  Take the quiz on netacad.com  Jeopardy review

In this chapter, you learned:  Devices

Chapter 4 Intro to Routing & Switching