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Networking Basics
- 1. NETWORKING-BASICS Lokesh Walase ( TY-Comp, Coep)
- 3. GNU Free Documentation License
- 4. Version 0.1
- 5. OK, but we are going for something different....
- 6. What is a Network ? Interconnection of devices ie printers , computers , telephones etc
- 7. “Physical Connectivity” among two or more devices
- 8. What is networking ? Communication between interconnected devices
- 9. TYPES : ( geographical scope ) LAN( Local Area Network ) ie within room, building or a university.
- 10. MAN( Metropolitian Area Network ) ie spans entire city.
- 11. WAN( Wide Area Network ) ie connects different cities, states , countries .
- 12. What do I need to set up network ? Devices like computer , printers , telephones etc
- 13. NIC ( Network Interface Card ) : it “physically” attaches a computer to a network .
- 14. Media : 1.Hub( always “Broadcasting” ) 2.Switch( 1 st “Broadcasting” & then “Unicasting” )
- 15. Requirements of network 3.Routers( connects different networks ) Cables are used to connect NIC with hub/switch/routers
- 16. For LAN we use CAT5 or CAT6 cables with RJ-45 connector ( Registered Jack )
- 17. Ethernet NIC card & Ethernet Connector with RJ-45 connector
- 18. RJ-45 connector & Crimper
- 19. Hub & Switch
- 20. Addressing in Networking Two types of address exists : 1.MAC address ie “Physical” Address ( 48 bit )
- 21. 2.IP address ie “Logical” Address ( Ipv4 is 32bit & Ipv6 is 128 bit) Right now Ipv4 is in use.
- 22. Command to find MAC & IP address is : “ifconfig”
- 23. Addressing in Networking MAC( Media Access Control ) address also called as : link-level addr, ethernet addr, station addr, H/W addr .
- 24. Each NIC is programmed at factory with unique MAC. .
- 25. 48-bits = Top 24 bits: vendor id
- 26. Bottom 24 bits: node id
- 27. MAC address Website to check your MAC address :
- 29. Ipv4 Addresses 32 bit number ( 4-octets of 8bits ) - Expressed in “dotted-quad” notation, e.g. 164.112.128.1
- 30. Two types : 1. Public
- 31. 2. Private
- 32. Five Classes in Public IP Class A : 8bits( Net ID) + 24bits( Host ID)= 32bits
- 33. Range : 0.x.y.z to 127.x.y.z
- 34. Total nodes in a network of type Class A is ( 2^7 )*(2^24-2)
- 35. Five Classes in Public IP Class B : 16bits( Net ID) + 16bits( Host ID)= 32bits
- 36. Higher 2bits are “10”
- 37. Range : 128.x.y.z to 191.x.y.z
- 38. Total nodes in a network of type Class B is ( 2^14)*(2^16-2)
- 39. Five Classes in Public IP Class C : 24bits( Net ID) + 8bits( Host ID)= 32bits
- 40. Higher 3 bits are “110”
- 41. Range : 192.x.y.z to 223.x.y.z
- 42. Total nodes in a network of type Class C is ( 2^21)*(2^8-2) Thus , Net-ID does work of “local router” .
- 43. Five Classes in Public IP Classes A,B,C support “unicasting” .
- 44. Class D : ( supports “multicasting” , group emails ) Higher 4 bits are (1110)
- 45. Range is (224).x.y.z to (239).x.y.z Class E : ( research & future purpose ) Higher 4 bits are (1111)
- 46. Range is (240).x.y.z to (253).x.y.z
- 47. Lets see an example If IP addr of system = 78.65.76.88 , find its “net ID” , 1 st host , last host & “Directed Broadcast Address” ( DBA )
- 48. ANS: 78.0.0.0 , 78.0.0.1 , 78.255.255.254 , 78.255.255.255 ( in that order )
- 49. “DBA” is used if packet has to be transmitted to all systems in a network.
- 50. Make all “host ID” bits as “1” .
- 51. One More Example... If IP addr of system = 203.89.79.66 , find its “net ID” , 1 st host , last host & “Directed Broadcast Address” ( DBA )
- 52. ANS : 203.89.79.00 , 203.89.79.01 , 203.89.79.254 , 203.89.79.255
- 53. Limited Broadcast Address It is 255.255.255.255 .
- 54. Used to send packet to all nodes within “same” network .
- 55. Till now all we saw was “2-level hierarchy”.
- 56. But what is actually used is “3-level heirarchy” , it has concept of “subnetting”.
- 57. Ranges of Private IP addr Till now all were “public”, now “private”IP's-
- 61. Can you guess the class-type of each ??
- 62. NOTE: 1.) has only 1 network , 2.) has max 16 networks & 3.) has max 256 networks .
- 63. Need of NAT router Network Address Translation .
- 64. Agent between public & private network.
- 65. Hides entire IP addr space behind single /group of IP addr.
- 66. DHCP & DHCP server Computers on IP networks must be configured b4 communication.
- 67. For eg, they must be given IP addr , default route etc .
- 68. This could be done manually. But DHCP does this for us.
- 69. It is – Dynamic Host Control Protocol .
- 70. DHCP & DHCP server DHCP is controlled by a DHCP-server.
- 71. DHCP enabled on your computer means you are letting DHCP server assign a IP( from a defined range of nos. )
- 72. DHCP server assigns a device IP , subnet mask , default gateway .
- 73. DNS & DNS server Domain Name System
- 74. Std technology for managing names of websites & Internet domains .
- 75. DNS server is like look-up table.
- 76. Can you think of something similar that we already use ??
- 77. DNS & DNS servers DNS servers communicate with each other using private protocols.
- 78. All DNS servers are arranged in heirarchy .
- 80. Networking commands ifconfig: display current config for all NIC's
- 81. ifconfig eth0 down : disable network card
- 82. ifconfig eth0 up : enable network card
- 83. host moodle.coep.org.in : DNS test
- 86. Networking commands ping localhost : if error then NIC is not physically installed or is bad .
- 87. ping moodle.coep.org.in : check connection
- 88. netstat -rn : ??
- 89. ssh & scp Ssh – secure shell , scp- secure copy.
- 90. Try this : ssh [email_address]
- 91. Try this : scp document.pdf [email_address] : ( send file at home folder of student )
- 92. Several combinations for scp at : http://www.examplenow.com/scp/