CCNA1_M9_TCP_IP_and_IP_Addressing (1130707)
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CCNA – Semester1Module 9TCP/IP and IP AddressingObjectives• Introduction to TCP/IP• Internet addresses• Obtaining an IP addressIntroduction to TCP/IPHistory and Future of TCP/IP• The U.S. Department of Defense(DoD) created the TCP/IPreference model because itwanted a network that couldsurvive any conditions.• In 1992 the standardization of anew generation of IP, IPv6, wassupported by the InternetEngineering Task Force (IETF)with 128 bits long.Application Layer••Handles high-levelprotocols, issues ofrepresentation, encoding,and dialog control.The TCP/IP protocol suitecombines all applicationrelated issues into one layerand ensures this data isproperly packaged beforepassing it on to the nextlayer.Transport Layer• The transport layerprovides transportservices including flowcontrol and reliabilityfrom the source host tothe destination host.• The transport layerconstitutes a logicalconnection betweenthe endpoints of thenetwork.Internet Layer• The purpose of theInternet layer is toselect the best paththrough the network forpackets to travel.• The main protocol thatfunctions at this layeris the Internet Protocol(IP).IP - Internet Protocol• IP: provides connectionless, best-effort delivery routingof packets.
IP is not concerned with the content of thepackets but looks for a path to the destination.• IP performs the following operations:– Defines a packet and an addressing scheme– Transfers data between the Internet layer and network access layers– Routes packets to remote hostsOther Internet Layer Protocols• Internet Control Message Protocol (ICMP)provides control and messaging capabilities.• Address Resolution Protocol (ARP) determinesthe data link layer address, MAC address, forknown IP addresses.• Reverse Address Resolution Protocol (RARP)determines IP addresses when the MAC addressis known.Network Access Layer• The network accesslayer is also called thehost-to-network layer.• Include the LAN andWAN technologydetails such as:Ethernet, Token-Ring,ISDN, Frame-Relay.• Include the mapping ofIP addresses tophysical hardwareaddresses andencapsulation of IPpackets into frames.Internet• Two computers, anywhere in the world, followingcertain hardware, software, and protocolspecifications, can communicate reliably.Internet AddressesNetwork and Host Addressing• IP address ishierarchical and hastwo parts:– First part identifies thenetwork where the system isconnected.– Second part identifies thatparticular system on thenetwork.IP Address Classes• IP addresses are divided into classes to definethe large, medium, and small networks.IP Address ClassesIP Address• The 127.0.0.0 network is reserved for loopbacktesting.• The Class D address class was created toenable multicasting in an IP address.
Amulticast address is a unique network addressthat directs packets with that destinationaddress to predefined groups of IP addresses.• A Class E address is reserved these addressesfor research.Reserved IP Address• Certain host addresses are reserved and cannotbe assigned to devices on a network.– Network address – Used to identify the network itself– Broadcast address – Used for broadcasting packets toall the devices on a networkNetwork address• Network address provide a convenient wayto refer to all of the addresses on aparticular network or subnetwork.• Two hosts with differing network addressrequire a device, typically a router, in orderto communicate.• An IP address that ends with binary 0s in allhost bits is reserved for the networkaddress.Broadcast address• Broadcast goes to every host with aparticular network ID number.• An IP address that ends with binary 1s in allhost bits is reserved for the directedbroadcast address.• An IP address with binary 1s in all networkbits and host bits is reserved for the localbroadcast address.Local broadcast address255.255.255.255STOPDirected broadcast address192.168.20.0192.168.20.255Example: 172.16.20.200•••••172.16.20.200 is Class B addressNetwork portion: 172.16Host portion:20.200Network address: 172.16.0.0Broadcast address: 172.16.255.255Public IP Address• In order to connect to the Internet, everymachines must have its own public IP address.Public IP addresses are unique.• With the rapid growth of the Internet, public IPaddresses were beginning to run out.
Newaddressing schemes are used so solve this:– Classless interdomain routing (CIDR)– IP version 6 (IPv6)– Network Address Translation (NAT)Private Address••Private networks can use private address to assign their machines inthe local network.RFC 1918 sets aside three blocks of IP addresses for private, internaluse.– Class A: 10.0.0.0– Class B: 172.16.0.0 Æ 172.31.0.0– Class C: 192.168.0.0 Æ 192.168.255.0•Connecting a network using private addresses to the Internetrequires translation (overloading) of the private addresses to publicaddresses.
This translation is served by NATValid address?•••••••150.100.255.255175.100.255.18195.234.253.0100.0.0.23188.258.221.176127.34.25.189224.156.217.73IPv4 versus IPv6•••Introduced by IETF in 1992, IPv6, known as IPng, uses 128 bitsrather than the 32 bits currently used in IPv4.IPv6 uses hexadecimal numbers to represent the 128 bits.IPv6 provides 640 sextrillion addresses. This version of IP shouldprovide enough addresses for future communication needs.Obtaining an IP addressObtaining an IP AddressStatic Assignment of IP Addresses• Each individual devicemust be configured withan IP address.• Keep very detailedrecords, becauseproblems can occur onthe network if you useduplicate IP addresses.Dynamic addressing• There are a some different methods that youcan use to assign IP addresses dynamically:– RARP: Reverse Address Resolution Protocol.– BOOTP: BOOTstrap Protocol.– DHCP: Dynamic Host Configuration Protocol.IPReverse Address Resolution ProtocolBOOTP IP• Network administrator creates a configuration file thatspecifies the parameters for each device.
The administratormust add hosts and maintain the BOOTP database.• BOOTP packets can include the IP address, as well as theaddress of a router, the address of a server, and vendorspecific information.Dynamic Host Configuration Protocol• Successor to BOOTP.• Automatically allows a host to obtain an IP addressfrom an IP pool• Use 4-steps IP registration and requires IP leasedtimeDHCP Initialization Sequence•Broadcast request and discoverDHCP server•Offer IP address, DHCP serveraddress and Default Gatewayaddress…•Request for the offered IPstatistics•Acknownledge the request,confirm registrationEncapsulationAddress Resolution Protocol• In order for devices to communicate, thesending devices need both the IP addressesand the MAC addresses of the destinationdevices.• ARP enables a computer to find the MACaddress of the computer that is associatedwith an IP address.Address resolution protocolARP table in hostMARARP operationARP Table:?MACMACA.B.C.1.2.3?IPIPData10.0.2.110.0.2.910.0.2.1A.B.C.1.2.310.0.2.5A.B.C.4.5.610.0.2.9A.B.C.7.8.9ABCARP operation: ARP requestIPIPMACMACWhat is your MAC Addr?A.B.C.1.2.3 ff.ff.ff.ff.ff.ff 10.0.2.1 10.0.2.910.0.2.1A.B.C.1.2.310.0.2.5A.B.C.4.5.610.0.2.9A.B.C.7.8.9ABCARP operation: CheckingIPIPMACMACWhat is your MAC Addr?A.B.C.1.2.3 ff.ff.ff.ff.ff.ff 10.0.2.110.0.2.9ist PaIhyTm10.0.2.1A.B.C.1.2.310.0.2.5A.B.C.4.5.610.0.2.9A.B.C.7.8.9ABCARP operation: ARP replyIPIPMACMACA.B.C.7.8.9 A.B.C.1.2.3 10.0.2.9 10.0.2.1This is my MAC Addr10.0.2.1A.B.C.1.2.310.0.2.5A.B.C.4.5.610.0.2.9A.B.C.7.8.9ABCARP operation: CachingARP Table:A.B.C.7.8.9 – 10.0.2.9IPIPMACMACA.B.C.1.2.3 A.B.C.7.8.9 10.0.2.1 10.0.2.9Data10.0.2.1A.B.C.1.2.310.0.2.5A.B.C.4.5.610.0.2.9A.B.C.7.8.9ABCARP: Local DestinationInternetwork communication• How to communicate with devices that arenot on the same physical network segment.Default gatewayDefault-Gateway•••In order for a device to communicate with another device onanother network, you must supply it with a default gateway.A default gateway is the IP address of the interface on therouter that connects to the network segment on which thesource host is located.In order for a device to send data to the address of a devicethat is on another network segment, the source device sendsthe data to a default gateway.Remote DestinationPacket forwarding• At layer 2, when encapsulating a frame, the host needsthe destination MAC address• The host will then compares IP address of source anddestination.– If the destination is on another network, then it will encapsulate theframe with the default-gateway MAC address.– If the destination is on the same net work, then it will use thedestination MAC address• Then it checks if the needed MAC address is in the ARPtable, if it is not proceed ARP request to find the neededMAC addressSummary•••••••Four layers of TCP/IP modelIP address, IP address classesNetwork address and broadcast addressPublic address and private addressIPv4 versus IPv6Static addressing, RARP, BOOTP, DHCPARP local and remote destination.
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