Dear Web User:
For Better View Of This Web Page, Please Use Any Latest Web Browser, Because Some Elements Are Not Work In The Old Web Browser (Might Not Be Displayed Properly Or Are Not Appearing properly!). The Target Audience Is Anyone Who Desires A Practical And Technical Introduction To The Field Of Networking. This Includes High School, Community College, And Lifelong-Learning Students Who Are Interested In Careers As Network Technicians, Network Engineers, Network Administrators, And Network Help-Desk Staff. FOR MORE REFERENCES:◙ - ➤ For More About - > DESCRIPTION OF EACH PROTOCOLS :
◙ - ➤ For More About - > BASIC COLLECTION OF NETWORKING CONCEPTS:
◙ - ➤ For More About - > BASIC NETWORKING QUESTIONS AND ANSWER:
◙ - ➤ For More Reference- > IP ROUTING QUESTIONS AND ANSWERS:
◙ - ➤ For More About - > TCP VS UDP:
ADDRESS RESOLUTION PROTOCOL (ARP)
ADDRESS RESOLUTION PROTOCOL (ARP):
The ADDRESS RESOLUTION PROTOCOL (ARP) Is A Telecommunication Protocol Used For Resolution Of Network Layer Addresses Into Link Layer Addresses, A Critical Function In Multiple-Access Networks. ARP Was Defined By RFC 826 In 1982. It Is Internet Standard STD 37. It Is Also The Name Of The Program For Manipulating These Addresses In Most Operating Systems. ARP Is Used To Convert An IP Address To A Physical Address Such As An Ethernet Address (Also Known As A MAC Address). ARP Has Been Implemented With Many Combinations Of Network And Data Link Layer Technologies, Such As Ipv4, Chaosnet, Decnet And Xerox PARC Universal Packet (PUP) Using IEEE 802 Standards, FDDI, X.25, Frame Relay And Asynchronous Transfer Mode (ATM). IPv4 Over IEEE 802.3 And IEEE 802.11 Is The Most Common Case. Address Resolution Protocol (ARP) Enables The Packaging Of Ip Data Into Ethernet Packages. It Is The System And Messaging Protocol That Is Used To Find The Ethernet (Hardware) Address From A Specific IP Number.◙ - ➤ For More Reference- > ARP Vs ICMP:
MEDIA ACCESS CONTROL (MAC)
MEDIA ACCESS CONTROL (MAC):
In The Seven-Layer OSI Model Of Computer Networking, MEDIA ACCESS CONTROL (MAC) Data Communication Protocol Is A Sublayer Of The Data Link Layer (Layer 2). The MAC Sublayer Provides Addressing And Channel Access Control Mechanisms That Make It Possible For Several Terminals Or Network Nodes To Communicate Within A Multiple Access Network That Incorporates A Shared Medium, E.G. Ethernet. The Hardware That Implements The MAC Is Referred To As A Medium Access Controller. The MAC Sublayer Acts As An Interface Between The Logical Link Control (LLC) Sublayer And The Network's Physical Layer. The MAC Layer Emulates A Full-Duplex Logical Communication Channel In A Multi-Point Network. This Channel May Provide Unicast, Multicast Or Broadcast Communication Service. MAC Address Is A Unique Identifier Assigned To Network Interfaces For Communications On The Physical Network Segment. MAC Addresses Are Used As A Network Address For Most IEEE 802 Network Technologies, Including Ethernet. Logically, MAC Addresses Are Used In The Media Access Control Protocol Sublayer Of The OSI Reference Model.THE OSI MODEL
OPEN SYSTEMS INTERCONNECTION MODEL (OSI):
The OPEN SYSTEMS INTERCONNECTION MODEL (OSI) Is A Conceptual Model That Characterizes And Standardizes The Internal Functions Of A Communication System By Partitioning It Into Abstraction Layers. The Model Is A Product Of The Open Systems Interconnection Project At The International Organization For Standardization (ISO), Maintained By The Identification ISO/IEC 7498-1.
The Model Groups Communication Functions Into Seven Logical Layers. A Layer Serves The Layer Above It And Is Served By The Layer Below It. For Example, A Layer That Provides Error-Free Communications Across A Network Provides The Path Needed By Applications Above It, While It Calls The Next Lower Layer To Send And Receive Packets That Make Up The Contents Of That Path. Two Instances At One Layer Are Connected By A Horizontal Connection On That Layer.
◙ - ➤ For More About - > FUNCTION OF OSI LAYERS:
TCP/IP PACKET PROCESSING SEQUENCE
TCP/IP PACKET PROCESSING SEQUENCE:
TCP/IP As The Communication Protocol Of Choice. As A Result, The Performance Of These Applications Is Heavily Dependent On The Efficient TCP/IP Packet Processing Within The Nodes. TCP/IP Processing Can Be Generally Divided Into Two Parts; Connection Management, And Data Path Processing.ICMP PACKET PROCESSING SEQUENCE - WHEN HOST A PINGS WITH HOST B
TO BE ABLE TO ROUTE PACKETS, A ROUTER NEEDS TO KNOW, AT MINIMUM, THE FOLLOWING:
1. Destination Address2. Neighbor Routers From Which It Can Learn About Remote Networks
3. Possible Routes To All Remote Networks
4. The Best Route To Each Remote Network
5. How To Maintain And Verify Routing Information
Host A------ (Fa0) Router A---------- Router B (Fa0) -------- Host B
WHEN A HOST A PINGS HOST B:
1. ICMP Creates A Packet With Minimum Destination And Source IP Address Of Host B 2. IP Then Determines If The Destination Is Local Or Over The Network 3. Then When The Default Gateway Is Determined, The Hardware Address Of The Ethernet Port Fa0 Of Router A Must Be Known Through Arp. (The Hardware Address Of The Switch Between The Host And Router Will Not Be Known, Only The Router). Hardware Addresses Only Stay On The Local LAN. 4. Then The ARP Cache Of Host A Is Checked To See If It’s In The Table. If Not, It Will Send An ARP Request. 5. The Packet Will Be Handed To The Data Link Layer For Framing. The Frame Has The Local And Destination Mac Addresses, Ethernet Type That Describes If It’s IP, IPX Or So On.. And FCS. 6. Then The Frame Is Handed Down The Physical Layer To Be Put Into Bits. 7. Every Device In The Collision Domain Receives This Frame And Checks Under The CRC And Checks The Answer In The FCS Field. If The Answer Doesn’t Match, The Frame Is Discarded, If It Does Match, Then The Hardware Destination Is Checked To See If It Matches Too. Then The Ether Type Field Is Checked For The Network Layer Protocol. 8. The Packet Is Pulled From The Frame. The Destination IP Is Checked, If Not In The Routing Table, The Packet Will Be Dropped And A Message Will Be Sent To Host A Saying “Destination Network Unreachable” 9. The Process Then Starts With The Ethernet 1 Checking The Arp Table For The Mac Address Of The Next Device And The Same Process Goes On Until Host B Receives The ICMP Message. If A Packet Is Lost On The Way Back You Will See “Request Timed Out”. If The Error Occurred Because Of A Known Issue, Such As The Destination Address Is Not In The Routing Table, Then You Will Get A “Destination Unreachable” Message.PACKET PROCESSING STEPS
PACKET PROCESSING STEPS:
The Most Important Thing For Exam Is To Remember Where, When, How, And Why MAC And IP Addresses Are Changing (Removed, Replaced). We Are Assuming That All Devices Have Just Been Turned On, Switch Is Layer 2 Switch And Pcs Are Properly Configured. PC1 Pings Remote PC2. As Two Pcs Are Separated By A Router, They Must Be On Different Networks (Subnets).
0. PC1 Determines That Destination IP Is On Remote Networks Using AND Ping Method Of Bit Calculating, So PC1 Will Use Its Default Gateway. 1. PC1 Looks In Its ARP Cache For Default Gateway IP Address. If Does Not Have It, It Sends ARP Request (Hey, You With IP 1.1.1.1, What Is Your MAC?) 2. Switch1 Gets The Frame; Frame Is ARP Broadcast, So Switch1 Processes The Frame. Adds MAC Source Address And Interface # It Came In. 3. ARP Is Broadcast (All FFFF’s), Switch1 Sends Out The Frame To All Ports In The Same VLAN Except The Receiving Port. (Frame Is Not Move To Upper Layers In OSI, Instead Data Link Takes Care Of It). 4. Broadcast ARP Reaches Your Router1. Router1 Accepts Frame Since Target IP Address Matches The Receiving Port's IP Address. 5. Router1 Updates Its ARP Table With Received Information And Replies To The Request With The Receiving Port's MAC Address. (I Am 1.1.1.1, My MAC Is 00-11-22-33-44-55) 6. Frame ARP Replay Now Is Going Back To PC1. 7. Switch1 Has MAC Of PC1, But Adds MAC Of Router1 And Sends Frame ONLY To PC1. 8. PC1 Receives APR Replay And Puts Info Into His ARP Cache. (For 5 Min. On Windows) 9. Now PC Can Continue Whatever Was Trying To Do In The First Place. PC1 Takes MAC Of Default Gateway Stored In Cache And Builds Packet With Upper Layer Protocols (ICMP In Our Case). 10. PC1 Sends Packet To PC2. Source IP Is PC1, Dest IP Is PC2, Source MAC Is PC1, Dest. MAC Is Router's Fa0/1. 11. Switch Receives Packet And Forwards Out Of Port Connected To Router1. It Does Not Do Anything Special Now. 12. Router1 Looks At MAC Dest. It Is For Him, Processes The Frame To Look At IP Dest. IP Destination Is Directly Connected, So It Will Process The Packet (Routers Know About Directly Connected Networks; PC2 Is Directly Connected). 13. If Router1 Does Not Have MAC Address Of PC2 In His Cache, It Will Send ARP Broadcast On The Interface Connected To PC2. Router1 Waits For ARP Replay From PC2, Not From Switch2, Although ARP Frame Will Pass Through The Switch2 On The Way To PC2 And Back. Switch 2 Is Doing Same Thing As SW1 Did: Builds MAC Table. 14. With PC2's MAC In Cache, Router1 Will Process Packet By Adding PC2's MAC Address As Dest. And His Outgoing Interface MAC As A Source. The Ips In The Packet Are The Same. 15. Switch2 Receives Frame, Adds MAC Address (If Not Already In The Table). 16. Switch2 (And Switch1 For That Matter) Will Process Frames If Ports Are Access Ports And Are On The Same VLAN. Two Conditions Are Often Omitted In CCNET Discussions As Vlans Are On ICND2 Exam. 17. Assuming Router1 And PC2 Are On The Same VLAN, Switch2 Will Forward Frame To PC2. 18. PC2 Receives Frame, Reads Dest. MAC, Strips Ethernet Header And Trailer, And Looks At Dest. IP. OK, It Is For Me And Processes. 19. In This Example, Packet Is An ICMP Packet So The ICMP Process Processes It By Sending Echo Replay Message. 20. IP Addresses Are Reversed. Source IP (PC1) Becomes Destination; Destination IP (PC2) Becomes Source. Data Link Layer Takes Packet And Encapsulates It With PC2's MAC As Source And MAC Of Default Gateway On Router1 (Destination IP Is On Different Network). 21. Packet Is On His Way Back To PC1. The Return Path Does Not Need ARP Process So The Return Trip Will Be Faster.
THE PROCESS RELATES TO OSI MODEL:
AT ROUTER AT LAYER 3:
1. The Routing Table Finds A Routing Entry To The Destination IP Address. 2. The Destination Network Is Directly Connected. The Router Sets Destination As The Next-Hop. 3. The Router Decrements The TTL On The Packet.ROUTER AT LAYER 2:
1. The Next-Hop IP Address Is A Unicast. The ARP Process Looks It Up In The ARP Table. 2. The Next-Hop IP Address Is Not In The ARP Table. The ARP Process Tries To Send An ARP Request For That IP Address And Drops This Packet.ARP AT ROUTER LAYER 2:
1. The ARP Process Constructs A Request For The Target IP Address. 2. The Device Encapsulates The PDU Into An Ethernet Frame. NOTES: At Step 3; If Switch Is Configured With An IP Address And Gateway (For Management Purpose) Then Alternate Step 3 Is: 3. ARP Request's Target IP Address Does Not Match The Receiving Port's IP Address On Switch1 'S VLAN 1 (If Configured), So Switch 1 Sends Out The Frame To All Ports In The Same VLAN Except The Receiving Port. (Frame Is Not Move To Upper Layers In OSI, Instead Data Link Takes Care Of It) Switches Do NOT Create ARP Broadcast And Do Not Care About Network Layer (3), Unless The Packet Is Destined For The Switch (Management Purpose). Switch Has ARP Table. It Is Empty At First Until You Configure IP Address For Management Purpose. Switch ARP Table Is Build When Hosts Ping The Switch, Not When Traffic Passes Thru The Switch.CISCO ROUTING AND SWITCHING PROCESSES
CISCO ROUTING AND SWITCHING PROCESSES:
THE ROUTING, OR FORWARDING, FUNCTION COMPRISES TWO INTERRELATED PROCESSES TO MOVE INFORMATION IN THE NETWORK: ◙ Making A Routing Decision By Routing◙ Moving Packets To The Next Hop Destination By Switching.
ROUTING PROCESSES
ROUTING PROCESSES:
The Routing Process Assesses The Source And Destination Of Traffic Based On Knowledge Of Network Conditions. Routing Functions Identify The Best Path To Use For Moving The Traffic To The Destination Out One Or More Of The Router Interfaces. The Routing Decision Is Based On Various Criteria Such As Link Speed, Topological Distance, And Protocol. Each Protocol Maintains Its Own Routing Information. Routing Is More Processing Intensive And Has Higher Latency Than Switching As It Determines Path And Next Hop Considerations. The First Packet Routed Requires A Lookup In The Routing Table To Determine The Route. The Route Cache Is Populated After The First Packet Is Routed By The Route-Table Lookup. Subsequent Traffic For The Same Destination Is Switched Using The Routing Information Stored In The Route Cache.SWITCHING PROCESSES
SWITCHING PROCESSES:
Through The Switching Process, The Router Determines The Next Hop Toward The Destination Address. Switching Moves Traffic From An Input Interface To One Or More Output Interfaces. Switching Is Optimized And Has Lower Latency Than Routing Because It Can Move Packets, Frames, Or Cells From Buffer To Buffer With Simpler Determination Of The Source And Destination Of The Traffic. It Saves Resources Because It Does Not Involve Extra Lookups. FOR EXAMPLE: Packets Are Received On The Fast Ethernet Interface And Destined For The FDDI Interface. Based On Information In The Packet Header And Destination Information Stored In The Routing Table, The Router Determines The Destination Interface. It Looks In The Routing Table Of The Protocol To Discover The Destination Interface That Services The Destination Address Of The Packet. The Destination Address Is Stored In Tables Such As ARP Tables For IP Or AARP Tables For Appletalk. If There Is No Entry For The Destination, The Router Will Either Drop The Packet (And Inform The User If The Protocol Provides That Feature) Or Discover The Destination Address By Some Other Address Resolution Process, Such As Through ARP. Layer 3 IP Addressing Information Is Mapped To The Layer 2 MAC Address For The Next Hop.BASIC SWITCHING PATHS
BASIC SWITCHING PATHS (Basic Switching Paths Are Described In The Following Sections):
◙ Process Switching◙ Fast Switching
◙ CEF Switching
◙ dCEF Switching
PROCESS SWITCHING:
In Process Switching The First Packet Is Copied To The System Buffer. The Router Looks Up The Layer 3 Network Address In The Routing Table And Initializes The Fast-Switch Cache. The Frame Is Rewritten With The Destination Address And Sent To The Outgoing Interface That Services That Destination. Subsequent Packets For That Destination Are Sent By The Same Switching Path. The Route Processor Computes The Cyclical Redundancy Check (CRC).FAST SWITCHING:
When Packets Are Fast Switched, The First Packet Is Copied To Packet Memory And The Destination Network Or Host Is Found In The Fast-Switching Cache. The Frame Is Rewritten And Sent To The Outgoing Interface That Services The Destination. Subsequent Packets For The Same Destination Use The Same Switching Path. The Interface Processor Computes The CRC.CEF SWITCHING:
When CEF Mode Is Enabled, The CEF FIB And Adjacency Tables Reside On The RP, And The RP Performs The Express Forwarding. You Can Use CEF Mode When Line Cards Are Not Available For CEF Switching Or When You Need To Use Features Not Compatible With Dcef Switching.dCEF SWITCHING:
In Distributed Switching, The Switching Process Occurs On VIP And Other Interface Cards That Support Switching. When Dcef Is Enabled, Line Cards, Such As VIP Line Cards Or GSR Line Cards, Maintain An Identical Copy Of The FIB And Adjacency Tables. The Line Cards Perform The Express Forwarding Between Port Adapters, Relieving The RSP Of Involvement In The Switching Operation. Dcef Uses An Inter Process Communication (IPC) Mechanism To Ensure Synchronization Of Fibs And Adjacency Tables On The RP And Line Cards.ROUTER SWITCHING FUNCTION
◙ Step 2: Examines The Destination IP Address Of The IP Packet To Find The Best Path In The Routing Table.
◙ Step 3 If The Router Finds A Path To The Destination, It Encapsulates The Layer 3 Packet Into A New Layer 2 Frame And Forwards The Frame Out The Exit Interface.
Devices Have Layer 3 IPv4 Addresses And Ethernet Interfaces Have Layer 2 Data Link Addresses. For Example: PC1 Is Configured With Ipv4 Address 192.168.1.10 And An Example MAC Address Of 0A-10. As A Packet Travels From The Source Device To The Final Destination Device, The Layer 3 IP Addresses Do Not Change. However, The Layer 2 Data Link Addresses Change At Every Hop As The Packet Is De-Encapsulated And Re-Encapsulated In A New Frame By Each Router. It Is Very Likely That The Packet Is Encapsulated In A Different Type Of Layer 2 Frame Than The One In Which It Was Received. For Example, An Ethernet Encapsulated Frame Might Be Received By The Router On A Fastethernet Interface, And Then Processed To Be Forwarded Out Of A Serial Interface As A Point-To-Point Protocol (PPP) Encapsulated Frame. PC1 Must Determine If The Destination Ipv4 Address Is On The Same Network. PC1 Determines Its Own Subnet By Doing An AND Operation On Its Own IPv4 Address And Subnet Mask. This Produces The Network Address That PC1 Belongs To. Next, PC1 Does This Same AND Operation Using The Packet Destination Ipv4 Address And The PC1 Subnet Mask. If The Destination Network Address Is The Same Network As PC1, Then PC1 Does Not Use The Default Gateway. Instead, PC1 Refers To Its ARP Cache For The MAC Address Of The Device With That Destination Ipv4 Address. If The MAC Address Is Not In The Cache, Then PC1 Generates An ARP Request To Acquire The Address To Complete The Packet And Send It To The Destination. If The Destination Network Address Is On A Different Network, Then PC1 Forwards The Packet To Its Default Gateway. To Determine The MAC Address Of The Default Gateway, PC1 Checks Its ARP Table For The IPv4 Address Of The Default Gateway And Its Associated MAC Address. If An ARP Entry Does Not Exist In The ARP Table For The Default Gateway, PC1 Sends An ARP Request. Router R1 Sends Back An ARP Reply. PC1 Can Then Forward The Packet To The MAC Address Of The Default Gateway, The Fa0/0 Interface Of Router R1. A Similar Process Is Used For IPv6 Packets. Instead Of The ARP Process, Ipv6 Address Resolution Uses Icmpv6 Neighbor Solicitation And Neighbor Advertisement Messages. IPv6-To-MAC Address Mappings Are Kept In A Table Similar To The ARP Cache, Called The Neighbor Cache.
FORWARD TO THE NEXT HOP
FORWARD TO THE NEXT HOP (1.2.1.3) The Following Processes Take Place When R1 Receives The Ethernet Frame From PC1:
1. R1 Examines The Destination MAC Address, Which Matches The MAC Address Of The Receiving Interface, Fastethernet 0/0. R1, Therefore, Copies The Frame Into Its Buffer. 2. R1 Identifies The Ethernet Type Field As 0x800, Which Means That The Ethernet Frame Contains An Ipv4 Packet In The Data Portion Of The Frame. 3. R1 De-Encapsulates The Ethernet Frame. 4. Because The Destination Ipv4 Address Of The Packet Does Not Match Any Of The Directly Connected Networks Of R1, R1 Consults Its Routing Table To Route This Packet. R1 Searches The Routing Table For A Network Address That Would Include The Destination Ipv4 Address Of The Packet As A Host Address Within That Network. In This Example, The Routing Table Has A Route For The 192.168.4.0/24 Network. The Destination Ipv4 Address Of The Packet Is 192.168.4.10, Which Is A Host Ipv4 Address On That Network. The Route That R1 Finds To The 192.168.4.0/24 Network Has A Next-Hop Ipv4 Address Of 192.168.2.2 And An Exit Interface Of Fastethernet 0/1. This Means That The Ipv4 Packet Is Encapsulated In A New Ethernet Frame With The Destination MAC Address Of The IPv4 Address Of The Next-Hop Router. BECAUSE THE EXIT INTERFACE IS ON AN ETHERNET NETWORK, R1 MUST RESOLVE THE NEXT-HOP IPV4 ADDRESS WITH A DESTINATION MAC ADDRESS USING ARP: 1. R1 Looks Up The Next-Hop Ipv4 Address Of 192.168.2.2 In Its ARP Cache. If The Entry Is Not In The ARP Cache, R1 Would Send An ARP Request Out Of Its Fastethernet 0/1 Interface And R2 Would Send Back An ARP Reply. R1 Would Then Update Its ARP Cache With An Entry For 192.168.2.2 And The Associated MAC Address. 2. The Ipv4 Packet Is Now Encapsulated Into A New Ethernet Frame And Forwarded Out The Fastethernet 0/1 Interface Of R1.PACKET ROUTING
PACKET ROUTING (1.2.1.4) The Following Processes Take Place When R2 Receives The Frame On Its Fa0/0 Interface:
1. R2 Examines The Destination MAC Address, Which Matches The MAC Address Of The Receiving Interface, Fastethernet 0/0. R2, Therefore, Copies The Frame Into Its Buffer. 2. R2 Identifies The Ethernet Type Field As 0x800, Which Means That The Ethernet Frame Contains An IPv4 Packet In The Data Portion Of The Frame. 3. R2 De-Encapsulates The Ethernet Frame. 4. Because The Destination Ipv4 Address Of The Packet Does Not Match Any Of The Interface Addresses Of R2, R2 Consults Its Routing Table To Route This Packet. R2 Searches The Routing Table For The Destination Ipv4 Address Of The Packet Using The Same Process R1 Used. 5. The Routing Table Of R2 Has A Route To The 192.168.4.0/24 Network, With A Next-Hop Ipv4 Address Of 192.168.3.2 And An Exit Interface Of Serial 0/0/0. Because The Exit Interface Is Not An Ethernet Network, R2 Does Not Have To Resolve The Next-Hop IPv4 Address With A Destination MAC Address. 6. The IPv4 Packet Is Now Encapsulated Into A New Data Link Frame And Sent Out The Serial 0/0/0 Exit Interface. When The Interface Is A Point-To-Point (P2P) Serial Connection, The Router Encapsulates The Ipv4 Packet Into The Proper Data Link Frame Format Used By The Exit Interface (HDLC, PPP, Etc.). Because There Are No MAC Addresses On Serial Interfaces, R2 Sets The Data Link Destination Address To An Equivalent Of A Broadcast (MAC Address: FF:FF:FF:FF:FF:FF).REACH THE DESTINATION (1.2.1.5) The Following Processes Take Place When The Frame Arrives At R3:
1. R3 Copies The Data Link PPP Frame Into Its Buffer. 2. R3 De-Encapsulates The Data Link PPP Frame. 3. R3 Searches The Routing Table For The Destination Ipv4 Address Of The Packet. The Routing Table Has A Route To A Directly Connected Network On R3. This Means That The Packet Can Be Sent Directly To The Destination Device And Does Not Need To Be Sent To Another Router. Because The Exit Interface Is A Directly Connected Ethernet Network, R3 Must Resolve The Destination Ipv4 Address Of The Packet With A Destination MAC Address: 1. R3 Searches For The Destination Ipv4 Address Of The Packet In Its Address Resolution Protocol (ARP) Cache. If The Entry Is Not In The ARP Cache, R3 Sends An ARP Request Out Of Its Fastethernet 0/0 Interface. PC2 Sends Back An ARP Reply With Its MAC Address. R3 Then Updates Its ARP Cache With An Entry For 192.168.4.10 And The MAC Address That Is Returned In The ARP Reply. 2. The IPv4 Packet Is Encapsulated Into A New Ethernet Data Link Frame And Sent Out The Fastethernet 0/0 Interface Of R3. 3. When PC2 Receives The Frame, It Examines The Destination MAC Address, Which Matches The MAC Address Of The Receiving Interface, Its Ethernet Network Interface Card (NIC). PC2, Therefore, Copies The Rest Of The Frame Into Its Buffer. 4. PC2 Identifies The Ethernet Type Field As 0x800, Which Means That The Ethernet Frame Contains An Ipv4 Packet In The Data Portion Of The Frame. 5. PC2 De-Encapsulates The Ethernet Frame And Passes The Ipv4 Packet To The IPv4 Process Of Its Operating System.CONCLUSION:
The Goal Of This Article Is To Give An Easy Way To Understand The “Packet Processing Steps" And Also We Hope This Guide Will Help Every Beginner Who Are Going To Start Cisco Lab Practice Without Any Doubts. Some Topics That You Might Want To Pursue On Your Own That We Did Not Cover In This Article Are Listed Here!Hands - On Experience Is An Invaluable Part Of Preparing For The Lab Exam And Never Pass Up An Opportunity To Configure Or Troubleshoot A Router ( If You Have Access To Lab Facilities, Take Full Advantage Of Them) There Is No Replacement For The Experience You Can Gain From Working In A Lab, Where You Can Configure Whatever You Want To Configure And Introduce Whatever Problems You Want To Introduce, Without Risk Of Disrupting A Production Network. Thank You And Best Of Luck
This Article Written Author By: Mr. Premakumar Thevathasan - CCNA And CCNP (Routing & Switching), MCSE, MCSA, MCSA - MSG, CIW Security Analyst, CompTIA Certified A+ And Etc.
WARNING AND DISCLAIMER:
Routers Direct And Control Much Of The Data Flowing Across Computer Networks. This Guide Provides Technical Guidance Intended To Help All Network Students, Network Administrators And Security Officers Improve Of Their Demonstrated Ability To Achieve Specific objectives Within Set Timeframes.This Document Carries No Explicit Or Implied Warranty. Nor Is There Any Guarantee That The Information Contained In This Document Is Accurate. Every Effort Has Been Made To Make All Articles As Complete And As Accurate As Possible, But No Warranty Or Fitness Is Implied.
It Is Offered In The Hopes Of Helping Others, But You Use It At Your Own Risk. The Author Will Not Be Liable For Any Special, Incidental, Consequential Or Indirect Any Damages Due To Loss Of Data Or Any Other Reason That Occur As A Result Of Using This Document. But No Warranty Or Fitness Is Implied. The Information Provided Is On An "As Is" Basic. All Use Is Completely At Your Own Risk.
Home Page Of - > The School Of Cisco Networking (SCN)
Page Of - > SCN InF4 TECH
Contact Details / About Us Page
To Send Email
No comments:
Post a Comment