sict ii - lecture 4
TRANSCRIPT
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TCP/IP PROTOCOL SUITE AND ROUTING FUNDAMENTALS
Mr. Froilan E. De Guzman
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Introduction to TCP/IP
TCP/IP in fact consists of dozens of different protocols, but only a few are the “main” protocols that define the core operation of the suite.
The Internet Protocol (IP) is the primary OSI network layer (layer three) protocol that provides addressing, datagram routing and other functions in an internetwork.
The Transmission Control Protocol (TCP) is the primary transport layer (layer four) protocol, and is responsible for connection establishment and management and reliable data transport between software processes on devices.
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TCP/IP Protocol Suite Layers and OSI Layers
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IPv4 vs. IPv6
Example of IPv4 (32-bits) 00110001.10000110.11000001.00000011 33.134.193.3
Example of IPv6 (128-bits) 0011111111111110:0001100100000000: 0110010101000101:0000000000000011: 0000001000110000:1111100000000010: 0111111010111111:0001001011000010 3FFE.1900.6545.3.230.F804.7EBF.12C2
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Application Layer
The last layer of both the OSI and the TCP/IP model.
It is the closest to the end user when interacting with software applications, such as sending and receiving email over a network
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Domain Name System
Domain is a group of computers that are associated with geographical location or their business types
Geographic Locations - .us, .uk, .ph Business Types:
.edu – educational sites - .com – Commercial sites .gov – Government sites - .org – Nonprofit sites .net – Network service - .mil – US military sites .int – International database/treaty organizations sites
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FTP and TFTP
FTP – is designed to download and upload files. The main purpose of this is transfer files from one computer to another.
TFTP – it is connectionless service that uses UDP. It is used on routers and switches to transfer configuration files and to transport files that supports TFTP
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Hypertext Transfer Protocol
It works with the world wide web, which is the fastest-growing and most used part of the Internet.
URL components: http:// - Identifies to the browser what protocol
should be used www. – Identifies what type of site is being
contacted by the browser Yahoo.com – Represents the domain entry of
the website /cgi/r3/ - Identifies the folder where the web
page is located on the server. Also, because no name is specified, the browser loads the default page identified by the server.
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Simple Mail Transfer Protocol It transport email messages in ASCII
format using TCP. You can connect to an SMTP server by
performing a ping test to the SMTP port (25) or to the POP3 port (110).
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Simple Network Management Protocol It is an application layer protocol that
facilitates the exchange of management information between network devices.
It enables network administrators to manage network performance, find and solve network problems and plan for network growth.
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Key Components of SNMP
Managed Device – It collect and store management information and make this information available to NMSs using SNMP.
Agent – It has local acknowledgement of management information and translates that information into a form compatible with SNMP.
Network Management System (NMS) – It provides the bulk of the processing and memory resources requires for network management
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Terminal Emulation
It provides the capability to remotely access another computer.
It enables you to log in to an Internet host and execute commands.
It commonly used for remote administration of servers and network equipment such as routers and switches.
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Transport Layer
It provides transport services from the host to the destination host.
It constitutes a logical connection between the endpoints of the network.
Transport services segments and reassemble data that is sent by several upper-layer applications onto the same transport layer data stream.
Transport layer data stream is a logical connection between the endpoints of a network.
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Transport Layer Protocols
Transport services using TCP include all the following services whereas using UDP provides only the first two Segmenting upper-layer application data Sending segments from one end device to
another end device Establishing end-to-end operations Flow control provided by sliding windows Reliability provided by sequence numbers and
acknowledgments.
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Flow Control
It avoids the problem of a transmitting host overflowing buffers in the receiving host.
Overflow can represent serious problems because they can result in the loss of data
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Establishing Connection
Sender Receiver
Synchronize
Synchronize
Negotiate Connection
Acknowledgement
Connection EstablishedData Transfer (Send Segments)
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Three-way Handshake
A sequence of messages exchanged between two or more network devices to ensure transmission synchronization before sending user data.
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Windowing
A flow-control mechanism requiring that the source device receive an acknowledgement from the destination after transmitting a certain amount of data.
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Acknowledgement
Notification sent from one network device to another to acknowledge that some vent occurred.
Sometimes abbreviated ACK
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Transmission Control Protocol It is a connection-oriented transport layer
protocol that provides reliable full-duplex data transmission
It is part of TCP/IP protocol stack. TCP is responsible for breaking messages
into segments, reassembling them at the destination station, resending anything that is not received, and reassembling messages from the segments
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Protocols Use TCP
File Transfer Protocol Hypertext Transfer Protocol Simple Mail Transfer Protocol Domain Name System
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TCP Segment Fields
Source Port – Number of calling port Destination Port – Number of called port Sequence Number – Number used to
ensure correct sequencing of the arriving data
Acknowledgement Number – Next expected TCP octet
HLEN – Number of 32-bit words in the header
Reserved – Set to 0 Code Bits – Control functions (such as
setup and termination of a session)
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TCP Segment Fields
Window – Number of octets that the sender is willing to accept
Checksum – Calculated checksum of the header and data fields
Urgent Pointer – Indication of the end of the urgent data
Options – One option currently defined – maximum TCP/IP segment size
Data – Upper-layer protocol data
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User Datagram Protocol
It is connectionless transport protocol in the TCP/IP protocol stack
It is a simple protocol that exchanges datagrams without acknowledgements or guaranteed delivery.
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Protocols Use UDP
Trivial File Transfer Protocol Simple Network Management Protocol Dynamic Host Configuration Protocol Domain Name System
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UDP Segment Fields
Source Port – Number of calling port Destination Port – Number of called
port Length – Number of bytes, including
header and data Checksum – Calculated checksum of
the header and data fields Data – Upper-layer protocol data
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Reserved TCP and UDP Port Numbers
Decimal Port
Number
Keyword Description
0 - Reserved
1 to 4 - Unassigned
5 RJE Remote Job Entry
7 Echo Echo
9 Discard Discard
11 Users Active Users
13 Daytime Daytime
15 NetStat Who is up, or netstat
17 Quote Quote of the Day
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Reserved TCP and UDP Port Numbers
Decimal Port
Number
Keyword Description
19 Chargen Character Generator
20 FTP-data File Transfer Protocol (Data)
21 FTP File Transfer Protocol
23 Telnet Terminal Connection
25 SMTP Simple Mail Transfer Protocol
37 Time Time of the Day
39 RLP Resource Location Protocol
42 NameServer Host name server
43 nickname Who is
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Reserved TCP and UDP Port Numbers
Decimal Port
Number
Keyword Description
53 Domain Domain Name Server
67 Bootps Bootstrap protocol server
68 Bootpc Bootstrap protocol client
69 TFTP Trivial File Transfer Protocol
75 - Any private dial-out service
77 - Any private RJE service
79 Finger Finger
80 HTTP Hypertext Transfer Protocol
95 SUPDUP SUPDUP Protocol
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Reserved TCP and UDP Port Numbers
Decimal Port
Number
Keyword Description
101 HOSTNAME NIC Host Name Server
102 ISO-TSAP ISO-TSAP
113 AUTH Authentication Service
117 UUCP-PATH UUCP Path Service
123 NTP Network Time Protocol
133 to 159 Unassigned
160 to 223 Reserved
224 to 241 Unassigned
242 to 255 Unassigned
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Internet Layer
The purpose of the Internet Layer is to send packets from the device using correct protocol that function at this layer.
Best path determination and packet switching occur at this layer
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Internet Layer Protocol
IP - Provides connectionless, best-effort delivery routing of packets. IP is not concerned with the content of the packet. Instead, it looks for a way to move the packets to their destination.
Internet Control Message Protocol (ICMP) – Provides control messaging capabilities.
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Internet Layer Protocol
Address Resolution Protocol (ARP) - Determines the data link layer addresses (MAC address) for known IP address.
Reverse Address Resolution Protocol (RARP) - Determines IPS addresses when data link layer addresses (MAC address) are known.
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IP Performs the Following:
Defining a packet and an addressing scheme
Transferring data between the Internet Layer and the Network Access Layer
Routing Packets to remote hosts
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Network Access Layer
It is also called the host-to-network layer. It is the layer that is concerned with all the
issues than an IP packets requires to make a physical link to the medium
It includes the LAN and WAN technology details and all the details contained in the OSI physical and data link layer
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Network Access Layer Protocols
Ethernet Fast Ethernet SLIP and PPP FDDI ATM, Frame Relay and SMDS ARP Proxy ARP RARP
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TCP/IP versus OSI (similarities) Both have layers Both have application layers, although
they include very different services Both have comparable transport and
network layers Packet-switched (not circuit-switched)
technology is assumed Networking professional need to know
both
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TCP/IP versus OSI (differences)
TCP/IP combines the presentation and session layers into its application layer
TCP/IP combines the OSI data link and physical layers into its network access layer.
TCP/IP appears simpler because it has fewer layers.
TCP/IP transport layer using UDP does not always guarantee reliable delivery of packets, as the transport layer in the OSI model does
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Internet Architecture
Internet is a deceptively simple idea that, when repeated on a large scale, enables nearly instantaneous worldwide data communications between anyone, anywhere at anytime.
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Limitation of LANs is that they don’t scale
Beyond a certain number of stations
Beyond a certain geographic separation
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Internet Architecture
The details of host computers, and LANs on which they reside, are separate from the details of getting messages from one network to another
The big-picture architecture for the Internet was to focus on the application layer interactions between the source and destination computers and any intermediate computers
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Concept of Internetworking
Building networks of networks A network of networks is called an
“internet”. The network that grew out of the DoD on
which the WWW runs is called “Internet”.
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Internetworking Characteristics
It must be scalable in the number of networks and computers attached.
It must be able to handle the transport of data across vast distances, including entire earth and near-end space.
It must be flexible to account for constant technological innovations.
It must adjust to dynamic conditions on the network.
It must be cost-effective It must be a system that permits anytime,
anywhere data communications to anyone.
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IP Addressing
A 32-bit IP address is broken into a network part and a host part. A bit or bit sequence at the start of each address determines the address’s class
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Hierarchical IP Address
Internet Address
1.0.0.0 2.0.0.0 3.0.0.0
10.1.0.0
50.0.0.0. . . . . . 255.0.0.0
10.3.0.010.2.0.010.4.0.0
10.0.0.0
10.5.0.0 10.255.0.0. . .
10.2.1.0 10.2.2.0 10.2.3.0 10.2.255.0
. . .. . .10.4.1.0 10.4.2.0 10.4.3.0 10.4.255.
0
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IP Address Class
Address Class
Number of Networks
Number of Hosts/
Network
A 126 16,777,216
B 16,384 65,535
C 2,097,152 254
D (multicast)
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Class A Addresses It was designed to support extremely
large networks. It uses only the first octet to indicate the
network addresses 127.0.0.0 network is reserved for
loopback testing, it cannot be signed to a network.
Any address that has value between 1 and 126 in the first octet is a Class A address.
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Class B Addresses
The first 2 bits of the first octet of a class B addresses are always 10.
The remaining 6 bits may be populated with either 1s or 0s.
Therefore the lowest number that can be represented with the class B is 10000000 (128), and the highest is number is 10111111 (191).
Any address that starts with a value in the range of 128 to 192 in the first octet is Class B address
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Class C Addresses
A Class C address begins with binary 110.
The lowest number that can be represented is 11000000 (192) and the highest number that can be represented is 11011111 (223).
If an address contains a number in the range of 192 to 223 in the first octet is Class C address.
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Class D Addresses
The Class D address space, much like the other address space, is mathematically constrained.
The first 4 bits of a Class D must be 1110.
The first octet range is 11100000 to 11101111, or 224 to 239.
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Class E Addresses
The first 4 bits of the first octet is 1111 The octet range is 11110000 to
11111111 (240 to 255) Class E addresses are reserved for IETF
(Internet Engineering Task Force) research.
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Reserved IP Address
Network Address are used to identify the network itself.
Broadcast address are used to broadcast packets to all devices on a network.
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Public IP Address
It is unique. No two machines that connect to public
network can have the same IP address. Because public IP are global and
standardized. Public IP addresses must be obtained
from an Internet service provider or a registry at some expense
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Private IP Address
RFC 18 sets aside three blocks of IP addresses for private, internal use.
Addresses are not routed on the Internet backbone, Internet routers immediately discard private IP addresses
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Private IP Addresses
IP Address Class RFC 1918 Internal Address Range
Class A 10.0.0.0 to 10.255.255.255
Class B 172.16.0.0 to 172.31.255.255
Class C 192.168.0.0 to 192.168.255.255
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Introduction to Subnetting
The way to conserve IP address. This method of dividing full network
address classes into smaller pieces has helped prevented complete IP address exhaustion
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Obtaining IP Address
Static Addressing RARP Addressing BOOTP Addressing DHCP Addressing
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Static Addressing
Each device must be configure with an IP address.
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RARP Addressing
It is a process wherein MAC address binding into IP addresses which allows some network devices to encapsulate data before sending it out on the
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BOOTP Addressing
It operates in a client/server environment and requires only a single packet exchange to obtain IP information
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DHCP Addressing
Dynamic Host Configuration Protocol is the successor of BOOTP. It allows to obtain an IP address dynamically without the network administrator’s having to set up an individual profile for that machine.
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What is Protocol?
It is standards-based set of rules that determines how computers communicate with each other across networks.
It also serves as the common denominator or medium by which different applications, hosts or systems communicate
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A Protocol Describes
The format that a message must take The way in which computers must
exchange a message within the context of a particular activity, such sending messages across networks.
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Routed Protocol
Any network protocol that provides enough information in its network layer address to allow a packet to be forwarded from one host to another based on the addressing scheme.
It defines the field formats within a packet.
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Example of Routed Protocols Internet Protocol Internetwork Packet Exchange AppleTalk
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Routing Protocol
It supports a routed protocol by providing mechanisms for sharing routing information.
Its messages move between router It allows the routers to communicate
with other routers to update and maintain tables
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Example of Routing Protocol
Routing Information Protocol Interior Gateway Routing Protocol Enhanced Interior Gateway Routing
Protocol Open Shortest Past First
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Connectionless
Data transfer without the existence of a virtual circuit.
It means that no dedicated circuit connection is required, as there would be for a telephone call.
The destination is not contacted before a packet is sent.
The recipient is not contacted before a letter is sent from one destination to another.
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Connection-Oriented
Data transfer that requires establishment of a virtual circuit.
It is established between the sender and the recipient before any data is transferred.
You place a call, a connection is established and the communication occurs
All packets travel sequentially across the same physical circuit.
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Encapsulation Changes in a Router
Receive Frame on Interface
Is a DataFor Router?
DiscardData
End
Is CRCCheck valid?
Remove frameHeader andTrailer from
Packet
ExtractDestinationIP address .from Packet
Is PacketTo be
Routed?
Process PacketOn the Router.Send Response
CompareDestination IPWith Routing
Table
Is thereA match?
Is thereA DefaultRouter?
Forward the dataPacket to the
Interface in theRouting Table Entry
Encapsulate theData PacketWith the newCRC trailer
EncapsulateThe Data Packet
In the appropriateFrame Header
Forward theNew Frame
End
DiscardData
Send ReplyMessage
DestinationUnreachable
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Anatomy of an IP Packet
Version – A 4 bit field that indicates the version of IP currently used. All devices must be running the same version of IP, or the device that is different rejects the packets.
IP Header Length (HLEN)– A 4-bit field that indicates the datagram header length in 32-bit words. This is the total length of all header information, accounting for the two variable length header fields.
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Anatomy of an IP Packet
Type of Service (TOS) – An 8-bit field that specifies the level of importance that has been assigned by a particular upper-layer protocol.
Total Length – A 16-bit field that specifies the length of the entire packet in bytes, including the data and header. To get the length of the data payload, subtract the HLEN from the total length
Identification – A 16-bit field that contains an integer that identifies the current datagram, this is sequence number
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Anatomy of an IP Packet
Flags – A 3-bit field in which the 2 low-order bits control fragmentation. The first bit specifies whether the packet can be fragmented, and the second bit specifies whether the packet is the last fragment in a series of fragmented packets.
Fragment Offset – A 13-bit field that helps piece together datagram fragments. This field allows the Flag field to end at a 16-bit boundary.
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Anatomy of an IP Packet
Time-To-Live (TTL) – An 8-bit field that maintains a counter that gradually decreases, in increments, to 0. At this point, the datagram is discarded, keeping the packets from looping endlessly.
Protocol – An 8-bit field that indicates with upper-layer protocol receives incoming packets after IP processing has been completed
Header Checksum – A 16-bit field that helps ensure IP header integrity
Source IP Address – A 32-bit field that specifies the sending node IP address.
Destination IP Address – A 32-bit field that specifies the receiving node IP address.
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Anatomy of an IP Packet
Option – A variable length field that allows IP to support various options, such as security.
Padding – Extra 0s are added to this field to ensure that the IP header is always a multiple of 32-bits
Data – A variable-length (maximum of 64KB) field that contains upper-layer information
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Routing
It is an OSI Layer 3 function. It functions as a hierarchical organization
scheme that allows individual addresses to be grouped and treated as a single unit until the individual address is needed for final delivery of the data.
It is the process of finding the most efficient path from one device to another
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Two functions of the Router
To maintain routing tables and make sure other routers know of changes in the network topology. This function is performed using routing protocol to communicate network information to other routers.
When packets arrive at an interface, the router must use the routing table to determine where to send the packets. It switches them to the appropriate interface, adds the necessary framing for the interface and then transmits the frame.
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Routed Protocol Operation
It includes any network protocol suite provides enough information in its network layer address to allow a router to forward it to the next device and ultimately to its destination.
It defines the format and use of the fields within a packet. Packets generally are conveyed from end system to end system.
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Routing Protocol Operation
It provides processes for sharing routing information
It allows routers to communicate with other routers to update and maintain the routing tables.
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Routing Table Components
Protocol Type – The type of routing protocol that created the routing table entry.
Destination/Next hop associations – Tells the router that a particular destination is either directly connected to the router or that it can be reached via another router called the next hop on the way to the final destination.
Routing Metrics – These are used to determine a route’s desirability.
Outbound Interface – The interface that the data must be sent out to reach the final destination
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References:
CCNA 1 and 2 By CISCO PRESS
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END OF CCNA MODULE I